JP2009117480A - Organic photoelectric conversion element, photosensor using the same, and color image pickup device - Google Patents

Organic photoelectric conversion element, photosensor using the same, and color image pickup device Download PDF

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JP2009117480A
JP2009117480A JP2007286479A JP2007286479A JP2009117480A JP 2009117480 A JP2009117480 A JP 2009117480A JP 2007286479 A JP2007286479 A JP 2007286479A JP 2007286479 A JP2007286479 A JP 2007286479A JP 2009117480 A JP2009117480 A JP 2009117480A
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photoelectric conversion
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charge transport
organic photoelectric
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Hokuto Seo
北斗 瀬尾
Satoshi Aihara
聡 相原
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Japan Broadcasting Corp
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Nippon Hoso Kyokai NHK
Japan Broadcasting Corp
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<P>PROBLEM TO BE SOLVED: To provide a photoelectric conversion element capable of reducing the dark current to smaller than that of an example of conventional photoelectric conversion elements and of maintaining or enhancing the photoelectric conversion efficiency of a conventional organic photoelectric conversion film. <P>SOLUTION: The organic photoelectric conversion element of the present invention is an organic photoelectric conversion film comprising a positive electrode, a negative electrode and an organic semiconductor layer interposed between these electrodes in which the organic semiconductor layer comprises photoelectric conversion layers and injection charge-transportation suppressing layers formed between the photoelectric conversion layers, and the injection charge-transportation suppressing layer is composed of an organic material having a HOMO level and LUMO level both of which are larger or smaller than both HOMO level and LUMO level of an organic material used in the photoelectric conversion layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、光信号を電気信号に変換する光電変換素子に係わり、光電変換を行う光電変換部に波長選択機能を有する有機光電変換材料を用いる有機光電変換素子に関する。   The present invention relates to a photoelectric conversion element that converts an optical signal into an electric signal, and relates to an organic photoelectric conversion element that uses an organic photoelectric conversion material having a wavelength selection function in a photoelectric conversion unit that performs photoelectric conversion.

現在、テレビカメラなどに用いられている撮像素子、すなわち光電変換素子においては、単結晶シリコンが光電変換部の材料として用いられている。
上記光電変換素子は、分光感度特性がブロードであり、青から赤まで可視光領域のすべての波長に対して感度を持つ。
このため、テレビカメラの解像度を低減させずにカラー対応とする際、入射光をＲＧＢの３原色にプリズムにより分解し、各原色毎にそれぞれ光電変換素子を設けるカラー撮像システム、すなわち３板式が主流の構成となっている。 Currently, single crystal silicon is used as a material for a photoelectric conversion unit in an imaging element used for a television camera or the like, that is, a photoelectric conversion element.
The photoelectric conversion element has a broad spectral sensitivity characteristic and is sensitive to all wavelengths in the visible light region from blue to red.
For this reason, when a television camera is adapted to color without reducing the resolution, a color imaging system in which incident light is separated into three primary colors of RGB by a prism and a photoelectric conversion element is provided for each primary color, that is, a three-plate type is mainstream. It becomes the composition of.

しかし、この３板式のカラー撮像システムは、プリズム及び３つの光電変換素子が必要であるため、小型・軽量化が困難である。
このため、小型・軽量化が容易に行える単板式構造が提案されており、例えば光電変換素子の各画素上にＲＧＢに対応する赤、緑及び青の色フィルタをベイヤーパターンに配列した構造が提案されている。
しかしながら、このベイヤーパターンの構造においては、青、緑及び赤のいずれか一色にて１画素を形成しているため、１画素につき真に得られる信号は１色のみで二色は周辺画素の信号から演算して求めることとなり、３板式に比較して偽色が発生しやすく、さらに所望の色以外の入射光は色フィルタにより吸収されてしまうため、入射した光の利用効率が低下する欠点がある。 However, since this three-plate color imaging system requires a prism and three photoelectric conversion elements, it is difficult to reduce the size and weight.
For this reason, a single plate structure that can be easily reduced in size and weight has been proposed. For example, a structure in which red, green, and blue color filters corresponding to RGB are arranged in a Bayer pattern on each pixel of a photoelectric conversion element is proposed. Has been.
However, in this Bayer pattern structure, one pixel is formed by any one color of blue, green and red, so only one color is obtained for each pixel, and two colors are signals of peripheral pixels. The false color is likely to occur compared to the three-plate type, and incident light other than the desired color is absorbed by the color filter. is there.

そのため、ある特定の波長の光、例えば赤、緑及び青の光のみを吸収し、この吸収した光に対し光電変換を行う有機材料を光電変換層とする有機光電変換素子、及び上記波長選択機能を有する有機光電変換素子において、入射光が光電変換されることで生成された電荷を読み出す読出回路を、２次元アレイ化した固体撮像素子、さらに３つの異なる色の波長の光、例えば赤、緑及び青の光に対し、それぞれ波長選択機能を有する光電変換素子を順次積層することにより、カラー固体撮像素子が提案されている（例えば、特許文献１及び２参照）。   Therefore, an organic photoelectric conversion element having a photoelectric conversion layer as an organic material that absorbs only light of a specific wavelength, for example, red, green, and blue light, and performs photoelectric conversion on the absorbed light, and the wavelength selection function described above In the organic photoelectric conversion element having a light source, a readout circuit for reading out charges generated by photoelectric conversion of incident light is a two-dimensional array of solid-state imaging elements, and light of three different color wavelengths such as red and green A color solid-state imaging device has been proposed by sequentially laminating photoelectric conversion elements each having a wavelength selection function for blue light and blue light (see, for example, Patent Documents 1 and 2).

現在主流の３板式カラー撮像システムを採用したカラーカメラと同等に高性能で、なおかつ小型軽量なカラーカメラを、上述した有機光電変換膜からなるカラー固体撮像素子を用いることで実現できると期待されている。   It is expected that a color camera that is as high-performance as a color camera that employs the current mainstream three-plate color imaging system, and that is small and lightweight can be realized by using the above-described color solid-state imaging device made of an organic photoelectric conversion film. Yes.

図を用いて従来の有機光電変換素子について簡単に説明する。図１３は、例えば陽極１１、正孔注入阻止層１２、光電変換層１３及び陰極１４からなる従来の有機光電変換素子の断面構造を示す概念図である。
この図においては、正孔注入阻止層１２及び光電変換層１３はいずれも有機材料を用いて形成されている。また、光電変換層１３には、ある特定の色の波長の光のみを吸収して光電変換する有機材料を用いる。 A conventional organic photoelectric conversion element will be briefly described with reference to the drawings. FIG. 13 is a conceptual diagram illustrating a cross-sectional structure of a conventional organic photoelectric conversion element including, for example, an anode 11, a hole injection blocking layer 12, a photoelectric conversion layer 13, and a cathode 14.
In this figure, both the hole injection blocking layer 12 and the photoelectric conversion layer 13 are formed using an organic material. The photoelectric conversion layer 13 uses an organic material that absorbs only light of a specific color wavelength and performs photoelectric conversion.

光電変換層１３が正孔輸送性の有機材料にて形成される場合、陽極１１から光電変換層１３への正孔の注入を抑制する目的で、陽極１１と光電変換層１３との間に正孔注入阻止層１２を設けることが多く行われている。この正孔注入阻止層１２には、材料として可視光領域の光を透過する電子輸送性（正孔を輸送し難い）有機材料を用いる。
一方、光電変換層１３が電子輸送性の有機材料にて形成される場合、上述と逆に、陰極１４から光電変換層１３に対する電子の注入を防止する目的で陰極１４と光電変換層１３との間に電子注入阻止層を設けることが多く行われている。この電子注入阻止層には、材料として可視光領域の光を透過する正孔輸送性（電子を輸送し難い）有機材料を用いる。
また、陽極１１及び陰極１４のいずれか一方、望ましくは双方が透明な導電性電極として形成されている。 When the photoelectric conversion layer 13 is formed of a hole transporting organic material, a positive electrode is provided between the anode 11 and the photoelectric conversion layer 13 for the purpose of suppressing injection of holes from the anode 11 to the photoelectric conversion layer 13. In many cases, the hole injection blocking layer 12 is provided. The hole injection blocking layer 12 is made of an organic material that transmits light in the visible light region (it is difficult to transport holes).
On the other hand, when the photoelectric conversion layer 13 is formed of an electron-transporting organic material, the cathode 14 and the photoelectric conversion layer 13 are formed for the purpose of preventing injection of electrons from the cathode 14 to the photoelectric conversion layer 13, contrary to the above. In many cases, an electron injection blocking layer is provided therebetween. For the electron injection blocking layer, a hole transporting property (difficult to transport electrons) that transmits light in the visible light region is used as a material.
In addition, one of the anode 11 and the cathode 14, preferably both are formed as transparent conductive electrodes.

図１３に示す従来の有機光電変換膜における理想的なエネルギー準位図を図１４に示す。図１４における符号Ｖは真空準位を示しており、符号Ｗ11は陽極１１の仕事関数、符号Ｈ12及びＬ12はそれぞれ正孔注入阻止層１２のＨＯＭＯ準位・ＬＵＭＯ準位である。さらに、符号Ｈ13・Ｌ13はそれぞれ光電変換層１３のＨＯＭＯ準位・ＬＵＭＯ準位を示し、符号Ｗ14は陰極１４の仕事関数を示している。
図１３における有機光電変換膜に対し、陽極１１に対して電圧Ｖpを印加し、陰極１４に対して電圧Ｖpより低い電圧Ｖmを印加した場合、すなわち有機光電変換膜が入射光を光電変換して、光電流が発生する動作について図１５を用いて説明する、図１５は、例えば、陽極１１に正の電圧Ｖpを印加し、陰極１４に負の電圧Ｖmを印加した状態において、有機光電変換膜に光を照射すると、光電変換層１３内では特定の色の波長の光（例えば、赤、緑及び青のいずれかの光）が吸収され、その強度に応じた電子・正孔対が発生する。 FIG. 14 shows an ideal energy level diagram in the conventional organic photoelectric conversion film shown in FIG. In FIG. 14, the symbol V indicates the vacuum level, the symbol W11 indicates the work function of the anode 11, and the symbols H12 and L12 indicate the HOMO level and the LUMO level of the hole injection blocking layer 12, respectively. Further, symbols H13 and L13 indicate the HOMO level and LUMO level of the photoelectric conversion layer 13, respectively, and symbol W14 indicates the work function of the cathode 14.
When the voltage Vp is applied to the anode 11 and the voltage Vm lower than the voltage Vp is applied to the cathode 14 with respect to the organic photoelectric conversion film in FIG. 13, that is, the organic photoelectric conversion film photoelectrically converts incident light. The operation of generating a photocurrent will be described with reference to FIG. 15. FIG. 15 shows an organic photoelectric conversion film in a state where a positive voltage Vp is applied to the anode 11 and a negative voltage Vm is applied to the cathode 14, for example. When light is irradiated onto the photoelectric conversion layer 13, light of a specific color wavelength (for example, light of any one of red, green, and blue) is absorbed in the photoelectric conversion layer 13, and an electron / hole pair corresponding to the intensity is generated. .

発生した電子・正孔対は、光電変換層１３に印加された電圧（Ｖp−Ｖm）による電界の効果により分離され、電子は正孔注入阻止層１２を通じて陽極１１に、正孔は陰極１４にそれぞれ移動し外部に読出され、光電流として検出される。
特開２００３−１５８２５４号公報 特開２００３−２３４４６０号公報 The generated electron / hole pairs are separated by the effect of the electric field generated by the voltage (Vp−Vm) applied to the photoelectric conversion layer 13. Electrons are transferred to the anode 11 through the hole injection blocking layer 12, and holes are transferred to the cathode 14. Each moves and is read out to be detected as a photocurrent.
JP 2003-158254 A JP 2003-234460 A

上述したように、光電変換層１３が外部に正孔及び電子を移動することによって光電流を得るため、この光電変換層１３における光電変換効率を向上させ、入射光に対して感度の良い有機光電変換膜を得るため、入射光により光電変換層１３内に発生した電子・正孔対を効率よく分離する必要がある。
したがって、電子・正孔対を効率良く分離するため、光電変換層１３内の電界を大きくする、すなわち陽極１１と陰極１４の間に印加する電圧を大きくすればよい。 As described above, since the photoelectric conversion layer 13 obtains a photocurrent by moving holes and electrons to the outside, the photoelectric conversion efficiency in the photoelectric conversion layer 13 is improved, and the organic photoelectric having high sensitivity to incident light is obtained. In order to obtain a conversion film, it is necessary to efficiently separate electron / hole pairs generated in the photoelectric conversion layer 13 by incident light.
Therefore, in order to efficiently separate electron / hole pairs, the electric field in the photoelectric conversion layer 13 may be increased, that is, the voltage applied between the anode 11 and the cathode 14 may be increased.

しかしながら、図１６に示すように、陽極１１と陰極１４との間にある程度以上の電圧を印加した場合、陽極１１から正孔注入阻止層１２を超えて光電変換層１３内に注入される正孔や陰極１４から光電変換層１３に注入される電子が大幅に増加してしまう。
上述のように光電変換層１３に注入された正孔や電子が暗電流として検出されるため、有機光電変換膜の信号対雑音比（Ｓ／Ｎ）を低下させる要因になる。 However, as shown in FIG. 16, when a certain voltage or more is applied between the anode 11 and the cathode 14, holes injected from the anode 11 into the photoelectric conversion layer 13 beyond the hole injection blocking layer 12. In addition, electrons injected from the cathode 14 into the photoelectric conversion layer 13 are greatly increased.
As described above, since holes and electrons injected into the photoelectric conversion layer 13 are detected as dark currents, the signal-to-noise ratio (S / N) of the organic photoelectric conversion film is reduced.

その対応として、暗電流を防ぐ手段として、陽極１１から光電変換層１３に正孔が注入しないように、図１３における正孔注入阻止層１２を厚膜化すること、あるいは正孔注入阻止層１２のＨＯＭＯ準位Ｈ１２と陽極１１の仕事関数Ｗ１１のエネルギー準位差を大きくすること、また、陰極１４から光電変換層１３に電子が注入しないように、図１３における光電変換層１３のＬＵＭＯ準位１３と陰極１４の仕事関数Ｗ１４のエネルギー準位差を大きくすること、あるいは光電変換層１３と陰極１４の間に光電変換層１３のＬＵＭＯ準位Ｌ１３に比べて小さなＬＵＭＯ準位を有し、陰極１４の仕事関数Ｗ１４とのエネルギー準位差がより大きくなるような材料で形成された電子注入阻止層を挿入することが考えられる。
しかしながら、正孔注入阻止層１２のＨＯＭＯ準位Ｈ１２と陽極１１の仕事関数Ｗ１１のエネルギー準位差を大きくする、および光電変換層１３のＬＵＭＯ準位Ｌ１３と陰極１４の仕事関数Ｗ１４のエネルギー準位差を大きくするためには、用いる材料を見直さなければならない。
また、正孔注入阻止層１２の厚膜化および電子注入阻止層を挿入した場合には、光電変換層１３に印加される電圧が減少するので、光電変換効率を低下させる要因となってしまう。結果として従来の有機光電変換膜の構造においては、光電変換効向上と暗電流の低減とがトレードオフの関係にあり、光電変換効率を低下させずに暗電流を低減することが難しいという課題があった。 Correspondingly, as a means for preventing dark current, the hole injection blocking layer 12 in FIG. 13 is made thick so that holes are not injected from the anode 11 into the photoelectric conversion layer 13, or the hole injection blocking layer 12 is used. Of the photoelectric conversion layer 13 in FIG. 13 so as to increase the energy level difference between the HOMO level H 12 and the work function W 11 of the anode 11 and to prevent electrons from being injected from the cathode 14 into the photoelectric conversion layer 13. it increases the energy level difference between the work function W 14 of level 13 and the cathode 14, or a small LUMO level than the LUMO level L 13 of the photoelectric conversion layer 13 between the photoelectric conversion layer 13 and the cathode 14 a, it is conceivable to insert an electron injection blocking layer energy level difference is formed in a more larger such materials with a work function W 14 of the cathode 14.
However, increasing the energy level difference between the work function W 11 HOMO level H 12 and the anode 11 of the hole injection blocking layer 12, and the work function of the LUMO level L 13 and the cathode 14 of the photoelectric conversion layer 13 W 14 In order to increase the energy level difference, the material used must be reviewed.
In addition, when the hole injection blocking layer 12 is thickened and the electron injection blocking layer is inserted, the voltage applied to the photoelectric conversion layer 13 decreases, which causes a decrease in photoelectric conversion efficiency. As a result, in the structure of the conventional organic photoelectric conversion film, there is a trade-off relationship between improvement in photoelectric conversion effect and reduction in dark current, and there is a problem that it is difficult to reduce dark current without reducing photoelectric conversion efficiency. there were.

本発明は、このような事情に鑑みてなされたもので、暗電流を従来例に比較して低減し、かつ光電変換効率を従来の有機光電変換膜と同様、あるいは向上させることが可能な光電変換素子を提供することを目的とする。   The present invention has been made in view of the above circumstances, and is a photoelectric device that can reduce the dark current as compared with the conventional example and can improve the photoelectric conversion efficiency in the same way as the conventional organic photoelectric conversion film. An object is to provide a conversion element.

本発明の有機光電変換素子は、陽極と、陰極と、これら電極間に介挿された有機半導体層からなる有機光電変換素子であって、前記有機半導体層が、光電変換層と、この光電変換層の間に形成された可視光領域の光を透過する有機材料からなる注入電荷輸送抑制層とから構成され、前記注入電荷輸送抑制層のＨＯＭＯ準位・ＬＵＭＯ準位が、光電変換層に用いられている有機材料のＨＯＭＯ準位・ＬＵＭＯ準位に比較し、いずれも大きい、またはいずれも小さい有機材料にて形成されていることを特徴とする。   The organic photoelectric conversion device of the present invention is an organic photoelectric conversion device comprising an anode, a cathode, and an organic semiconductor layer interposed between these electrodes, the organic semiconductor layer comprising a photoelectric conversion layer and the photoelectric conversion layer. An injection charge transport suppression layer made of an organic material that transmits light in the visible light region formed between the layers, and the HOMO level / LUMO level of the injection charge transport suppression layer is used for the photoelectric conversion layer Compared to the HOMO level and LUMO level of the organic material used, the organic material is formed of an organic material that is both large or small.

本発明の有機光電変換素子は、前記光電変換層が特定の波長の光のみを吸収し、該光を光電変換する波長選択機能を有する有機材料で形成されていることを特徴とする。   The organic photoelectric conversion element of the present invention is characterized in that the photoelectric conversion layer is formed of an organic material having a wavelength selection function of absorbing only light of a specific wavelength and photoelectrically converting the light.

本発明の有機光電変換素子は、前記注入電荷輸送抑制層が０．５ｎｍ〜５０ｎｍの厚さで構成されていることを特徴とする。   The organic photoelectric conversion element of the present invention is characterized in that the injected charge transport suppression layer is formed with a thickness of 0.5 nm to 50 nm.

本発明の有機光電変換素子は、前記注入電荷輸送抑制層が前記光電変換層に１層あるいは複数層介挿されていることを特徴とする。   The organic photoelectric conversion element of the present invention is characterized in that the injection charge transport suppression layer is interposed in the photoelectric conversion layer by one layer or a plurality of layers.

本発明の光センサは、上記いずれかの有機光電変換素子と、入射光により生成された電荷を読み出す読み出し回路を備えたことを特徴とする。   An optical sensor according to the present invention includes any one of the above-described organic photoelectric conversion elements and a readout circuit that reads out charges generated by incident light.

本発明のカラー撮像素子は、上記いずれかの有機光電変換素子のなかで、青色に波長選択機能を有する有機光電変換素子と、緑色に波長選択機能を有する有機光電変換素子と、赤色に波長選択機能を有する有機光電変換素子と、前記各有機光電変換素子で生じた電荷を読み出す読み出し回路を順次積層して形成されていることを特徴とする。   The color image sensor of the present invention is one of the above organic photoelectric conversion elements, an organic photoelectric conversion element having a wavelength selection function in blue, an organic photoelectric conversion element having a wavelength selection function in green, and a wavelength selection in red The organic photoelectric conversion element having a function and a readout circuit for reading out electric charges generated in the organic photoelectric conversion elements are sequentially stacked.

以上説明したように、本発明によれば、光電変換層を形成する有機材料のＨＯＭＯ準位・ＬＵＭＯ準位に比較し、ＨＯＭＯ準位・ＬＵＭＯ準位が、いずれも大きいかいずれも小さく、なおかつ可視光領域の光を透過する注入電荷輸送抑制層を、電荷が輸送される方向に対して垂直に光電変換層に挿入することにより、電極から注入される電荷の電極間における移動が抑制され、暗電流を減少させることが可能となる。
また、本発明によれば、入射光により発生した信号電荷（電子および正孔）の電極間における移動も抑制されるが、一方で、電荷注入輸送抑制層と光電変換層とのエネルギー準位差を有する接触面における酸化還元反応により、入射光により発生した電子・正孔対の分離が接触面近傍で促進されるため、全体として光電変換効率の高い有機光電変換膜が得ることができる。 As described above, according to the present invention, the HOMO level / LUMO level is larger or smaller than the HOMO level / LUMO level of the organic material forming the photoelectric conversion layer, and By inserting an injection charge transport suppression layer that transmits light in the visible light region into the photoelectric conversion layer perpendicular to the direction in which charges are transported, the movement of charges injected from the electrodes between the electrodes is suppressed, Dark current can be reduced.
In addition, according to the present invention, the movement of signal charges (electrons and holes) generated by incident light between the electrodes is also suppressed. On the other hand, the energy level difference between the charge injection and transport suppression layer and the photoelectric conversion layer is suppressed. By the oxidation-reduction reaction on the contact surface having, separation of electron-hole pairs generated by incident light is promoted in the vicinity of the contact surface, so that an organic photoelectric conversion film having high photoelectric conversion efficiency as a whole can be obtained.

（実施の形態１）
以下、図１を用いて本発明による有機光電変換素子を説明する。図１は本発明の有機光電変換素子の断面構成を示す概念図である。
この図において、本発明の有機光電変換素子は、例えば、陽極４１、正孔注入阻止層４２、光電変換層４３Ａ、注入電荷輸送抑制層４４、光電変換層４３Ｂ、陰極４５から構成されている。図１３の従来例と異なる点は、光電変換層４３Ａ及び４３Ｂの間に注入電荷輸送抑制層４４が挿入されている点である。
図１の有機光電変換素子は、陰極４５に対し陽極４１に比較して低い電圧、例えば陰極４５に対して負の電圧、陽極４１に対して正の電圧が印加されている状態にて動作、すなわち上記光電変換層４３Ａ及び４３Ｂの吸収した光量に対応した電荷を生成し、この電荷に応じた電流が流れる。図１の断面構造を有する有機光電変換素子の電圧が印加されていないときの各層のエネルギー準位を図２に示す。 (Embodiment 1)
Hereinafter, the organic photoelectric conversion element by this invention is demonstrated using FIG. FIG. 1 is a conceptual diagram showing a cross-sectional configuration of the organic photoelectric conversion element of the present invention.
In this figure, the organic photoelectric conversion element of the present invention includes, for example, an anode 41, a hole injection blocking layer 42, a photoelectric conversion layer 43A, an injected charge transport suppression layer 44, a photoelectric conversion layer 43B, and a cathode 45. The difference from the conventional example of FIG. 13 is that an injected charge transport suppression layer 44 is inserted between the photoelectric conversion layers 43A and 43B.
The organic photoelectric conversion element of FIG. 1 operates in a state where a lower voltage than the anode 41 is applied to the cathode 45, for example, a negative voltage is applied to the cathode 45 and a positive voltage is applied to the anode 41. That is, a charge corresponding to the amount of light absorbed by the photoelectric conversion layers 43A and 43B is generated, and a current corresponding to the charge flows. The energy level of each layer when the voltage of the organic photoelectric conversion element having the cross-sectional structure of FIG. 1 is not applied is shown in FIG.

ここで、上記陽極４１及び陰極４５には、形成材料として、例えばインジウム酸化物（ＩＯ）、インジウム・スズ酸化物（ＩＴＯ）、インジウム・亜鉛酸化物（ＩＺＯ）などの金属酸化物をスパッタ法や加熱蒸着法などを利用して１０ｎｍ〜３００ｎｍの厚さで堆積した透明導電性薄膜を用いる。また、陽極４１及び陰極４５には、白金、金、銀、アルミニウムなどの金属材料を加熱蒸着法やスパッタ法あるいは電子ビーム蒸着法などを用い、５ｎｍ〜３０ｎｍと薄く堆積した半透明金属薄膜を用いても良い。   Here, for the anode 41 and the cathode 45, for example, a metal oxide such as indium oxide (IO), indium tin oxide (ITO), indium zinc oxide (IZO) or the like is formed by a sputtering method or the like. A transparent conductive thin film deposited with a thickness of 10 nm to 300 nm using a heating vapor deposition method or the like is used. For the anode 41 and the cathode 45, a semi-transparent metal thin film in which a metal material such as platinum, gold, silver, or aluminum is thinly deposited to 5 nm to 30 nm by using a heat evaporation method, a sputtering method, an electron beam evaporation method, or the like is used. May be.

また、光電変換層４３Ａ及び４３Ｂには、形成材料として、特定の波長の光を吸収する波長選択機能を有する有機光電変換材料であれば何を用いてもよいが、例えばスチルベン誘導体、ベンゾキサゾール誘導体、縮合芳香族炭素環（ペリレン誘導体、アントラセン誘導体、テトラセン誘導体など）、メロシアニン誘導体、オキサジアゾール誘導体、ジアミン誘導体、チオフェン誘導体、ＰｔやＥｕ（ユウロピウム）、Ｓｎ、ＡＩ、Ｉｒ、Ｚｎなどの金属錯体、ＤＣＭ誘導体、アゾ系有機顔料、多環式系有機顔料(フタロシアニン類、キナクリドン類、ポルフィリン類など)を蒸着法や塗布法を利用して３０ｎｍ〜３００ｎｍの厚さで堆積した薄膜を用いることができる。すなわち、光電変換層４３Ａ及び４３Ｂは、入射光における特定の波長の光を吸収し、電子正孔対を生成するものであり、それ以外の波長の入射光の成分を透過させる。
また、光電変換層４３Ａ及び４３Ｂには、上記有機材料を複数種混合した薄膜あるいは積層した薄膜を用いても良い。 The photoelectric conversion layers 43A and 43B may be any organic photoelectric conversion material having a wavelength selection function that absorbs light of a specific wavelength as a forming material. For example, stilbene derivatives, benzoxazole Derivatives, condensed aromatic carbocycles (perylene derivatives, anthracene derivatives, tetracene derivatives, etc.), merocyanine derivatives, oxadiazole derivatives, diamine derivatives, thiophene derivatives, metals such as Pt and Eu (europium), Sn, AI, Ir, Zn Use a thin film obtained by depositing a complex, a DCM derivative, an azo organic pigment, a polycyclic organic pigment (phthalocyanines, quinacridones, porphyrins, etc.) with a thickness of 30 nm to 300 nm by using a vapor deposition method or a coating method. Can do. That is, the photoelectric conversion layers 43A and 43B absorb light of a specific wavelength in incident light and generate electron-hole pairs, and transmit components of incident light of other wavelengths.
The photoelectric conversion layers 43A and 43B may be a thin film obtained by mixing or laminating a plurality of the above organic materials.

陽極４１から光電変換層４３に注入され、ノイズとして検出される正孔を抑制するため、正孔注入阻止層４２には、可視光領域の光を透過する電子輸送性の有機材料で、かつ光電変換層４３のＨＯＭＯ準位Ｈ４３に比べて大きいＨＯＭＯ準位を有する材料であれば何を用いてもよいが、例えばチオフェン誘導体、ベンゾキサゾール誘導体、オキサジアゾール誘導体、トリアジン誘導体、スチルベン誘導体、ペリレン誘導体、ＴＣＮＱ誘導体、ＳｎやＡ１、Ｚｎなどの金属錯体、フラーレン、縮合芳香族炭素環を蒸着法や塗布法を利用して１０ｎｍ〜１００ｎｍの厚さで堆積した薄膜を用いることができる。 In order to suppress holes that are injected from the anode 41 into the photoelectric conversion layer 43 and detected as noise, the hole injection blocking layer 42 is made of an electron-transporting organic material that transmits light in the visible light region, and photoelectrically. What may be used as long as the material has a large HOMO level than the HOMO level H 43 of the conversion layer 43 is, for example thiophene derivatives, benzoxazole derivatives, oxadiazole derivatives, triazine derivatives, stilbene derivatives, A thin film in which a perylene derivative, a TCNQ derivative, a metal complex such as Sn, A1, or Zn, fullerene, or a condensed aromatic carbocycle is deposited to a thickness of 10 nm to 100 nm using an evaporation method or a coating method can be used.

注入電荷輸送抑制層４４には、光電変換層４３Ａ及び４３Ｂを形成する材料のＨＯＭＯ準位及びＬＵＭＯ準位に比較して、ＨＯＭＯ準位、ＬＵＭＯ準位のいずれも大きいかあるいはいずれも小さく、可視光領域の光を透過する有機材料であれば何を用いてもよい。
ここで、注入電荷輸送抑制層４４には、上述したＨＯＭＯ準位及びＬＵＭＯ準位を有する、例えば、チオフェン誘導体、ベンゾキサゾール誘導体、オキサジアゾール誘導体、トリアジン誘導体、スチルベン誘導体、ペリレン誘導体、ＴＣＮＱ誘導体、ＳｎやＡｌ、Ｚｎなどの金属錯体、フラーレン、縮合芳香族炭素環、カルバゾール誘導体、フタロシアニン誘導体、トリフェニレン誘導体、トリフェニルアミン誘導体を用いることができる。 In the injected charge transport suppression layer 44, both the HOMO level and the LUMO level are larger or smaller than the HOMO level and the LUMO level of the material forming the photoelectric conversion layers 43A and 43B, and visible. Any organic material that transmits light in the light region may be used.
Here, the injected charge transport suppression layer 44 has the above-described HOMO level and LUMO level, for example, thiophene derivative, benzoxazole derivative, oxadiazole derivative, triazine derivative, stilbene derivative, perylene derivative, TCNQ derivative. Metal complexes such as Sn, Al and Zn, fullerenes, condensed aromatic carbocycles, carbazole derivatives, phthalocyanine derivatives, triphenylene derivatives and triphenylamine derivatives can be used.

また、注入電荷輸送抑制層４４には、すでに述べた正孔注入阻止層４２と同一の材料で形成してもよいし、異なる材料で形成してもよい。
また、注入電荷輸送抑制層４４は、蒸着法や塗布法を利用して０．５ｎｍ〜５０ｎｍの厚さにて、より望ましくは１ｎｍ〜２０ｎｍの厚さにて、光電変換層４３Ａ及び４３Ｂに比較して薄く形成する。ここで、注入電荷輸送抑制層４４の厚さは、設計値として、陽極４１及び陰極４５間に印加される電圧が分圧された際に、光電変換層４３Ａ及び４３Ｂに電子正孔対の発生及び分離に必要な電圧が印加される厚さに制御される必要がある。
さらに、上記光電変換層間に複数の、例えば２層〜５層の注入電荷輸送抑制層を挿入してもよく、例えば図３に示すように、光電変換層４３Ａ、４３Ｂ及び４３Ｃのそれぞれの間に、電荷輸送４４Ａ、４４Ｂの２層を挿入しても良い。 The injected charge transport suppression layer 44 may be formed of the same material as the hole injection blocking layer 42 already described, or may be formed of a different material.
Further, the injected charge transport suppression layer 44 is compared with the photoelectric conversion layers 43A and 43B by using a vapor deposition method or a coating method at a thickness of 0.5 nm to 50 nm, more preferably at a thickness of 1 nm to 20 nm. And thinly formed. Here, the thickness of the injected charge transport suppression layer 44 is, as a design value, the generation of electron-hole pairs in the photoelectric conversion layers 43A and 43B when the voltage applied between the anode 41 and the cathode 45 is divided. In addition, it is necessary to control the thickness to which a voltage necessary for separation is applied.
Further, a plurality of, for example, two to five layers of injected charge transport suppression layers may be inserted between the photoelectric conversion layers, for example, as shown in FIG. 3, between the photoelectric conversion layers 43A, 43B and 43C. Two layers of charge transport 44A and 44B may be inserted.

また、図１及び図３に示す形態のほかに、正孔注入阻止層４２を省いた形態や光電変換層４３Ｂと陰極４５との間に電子注入阻止層を有する構成としてもよい。
図１の構成において、陰極４５から注入され光電変換層４３Ｂに注入されてノイズとして検出される電子を抑制するため、電子注入阻止層は光電変換層４３ＢのＬＵＭＯ準位に対し、低いＬＵＭＯ準位を有する有機材料を用いる。ここで、光電変換層４３Ａ及び４３Ｂに電子輸送性を有する材料が用いられている場合に、特に有効に電子注入阻止層が機能する。
ここで、電子注入阻止層には、可視光領域の光を透過する正孔輸送性の有機材料であれば何を用いてもよいが、例えばチオフェン誘導体、オキサジアゾール誘導体、カルバゾール誘導体、フタロシアニン誘導体、トリフェニレン誘導体、トリフェニルアミン誘導体などを用いることができる。 In addition to the modes shown in FIGS. 1 and 3, a configuration in which the hole injection blocking layer 42 is omitted or a configuration in which an electron injection blocking layer is provided between the photoelectric conversion layer 43 </ b> B and the cathode 45 may be employed.
In the configuration of FIG. 1, in order to suppress electrons injected from the cathode 45 and injected into the photoelectric conversion layer 43B and detected as noise, the electron injection blocking layer has a lower LUMO level than the LUMO level of the photoelectric conversion layer 43B. An organic material having Here, when a material having an electron transport property is used for the photoelectric conversion layers 43A and 43B, the electron injection blocking layer functions particularly effectively.
Here, the electron injection blocking layer may be any hole-transporting organic material that transmits light in the visible light region. For example, thiophene derivatives, oxadiazole derivatives, carbazole derivatives, phthalocyanine derivatives , Triphenylene derivatives, triphenylamine derivatives and the like can be used.

次に、図１に示す構成の動作について、図４を用いて説明する。
図４の構成は、光電変換膜４３Ａ及び４３ＢのＨＯＭＯ準位及びＬＵＭＯ準位に比較して、それぞれのエネルギー準位より大きいＨＯＭＯ準位、ＬＵＭＯ準位を有し、かつ可視光領域の波長の光を透過する注入電荷輸送抑制層４５を、光電変換膜４３Ａ及び４３Ｂの厚さに比較して薄く挿入した有機光電変換素子の各膜のエネルギー準位図を示している。
図４に示すように、正孔が陽極４１から正孔注入阻止層４２を超え、光電変換層４３Ａに達したとしても、この正孔は光電変換層４３ＡのＨＯＭＯ準位と、注入電荷輸送抑制層４４のＨＯＭＯ準位との境界におけるエネルギー障壁のために、光電変換層４３Ｂへの移動が抑制され、注入電荷輸送抑制層４４を挿入しない場合に比較して陽極４１と対向する陰極４５に到達しにくくなる。 Next, the operation of the configuration shown in FIG. 1 will be described with reference to FIG.
The configuration of FIG. 4 has HOMO levels and LUMO levels larger than the respective energy levels as compared with the HOMO levels and LUMO levels of the photoelectric conversion films 43A and 43B, and has a wavelength in the visible light region. The energy level diagram of each film | membrane of the organic photoelectric conversion element which inserted the injection charge transport suppression layer 45 which permeate | transmits light thinly compared with the thickness of the photoelectric converting films 43A and 43B is shown.
As shown in FIG. 4, even when holes exceed the hole injection blocking layer 42 from the anode 41 and reach the photoelectric conversion layer 43A, the holes are suppressed in the HOMO level of the photoelectric conversion layer 43A and injection charge transport suppression. Due to the energy barrier at the boundary of the layer 44 with the HOMO level, the movement to the photoelectric conversion layer 43B is suppressed, and the cathode 45 facing the anode 41 is reached compared with the case where the injection charge transport suppression layer 44 is not inserted. It becomes difficult to do.

同様に、陰極４５から光電変換層４３Ｂに注入された電子は、注入電荷輸送抑制層４４のＬＵＭＯ準位と光電変換層４３ＡのＬＵＭＯ準位との境界におけるエネルギー障壁により、陰極４５と対向する陽極４１に到達しにくくなる。
すなわち、有機光電変換素子において、光電変換層４３Ａ及び４３Ｂの間に注入電荷輸送抑制層４４を、光電変換膜４３Ａ及び４３Ｂの厚さに比較して薄く挿入することにより、陽極４１から注入される正孔と、陰極４５から注入される電子との移動を抑制することができ、暗電流を低減する効果がある。 Similarly, electrons injected from the cathode 45 into the photoelectric conversion layer 43B are anodes facing the cathode 45 due to an energy barrier at the boundary between the LUMO level of the injected charge transport suppression layer 44 and the LUMO level of the photoelectric conversion layer 43A. 41 is difficult to reach.
That is, in the organic photoelectric conversion element, the injected charge transport suppression layer 44 is inserted between the photoelectric conversion layers 43A and 43B so as to be thinner than the thickness of the photoelectric conversion films 43A and 43B, thereby being injected from the anode 41. The movement of holes and electrons injected from the cathode 45 can be suppressed, and there is an effect of reducing dark current.

一方、注入電荷輸送抑制層４４の膜厚が光電変換層４３Ａ及び４３Ｂに比較して薄いため、光電変換層４３Ａおよび４３Ｂに印加される分圧は、光電変換層４３Ａ及び４３Ｂに注入電荷輸送抑制層４４を挿入しない場合に比較して、ほとんど低下せず同等の電圧が印加される。
また、光電変換層４３Ａ及び４３Ｂ内の電界による電子正孔対の分離効果に加え、注入電荷輸送抑制層４４と光電変換層４３Ｂとの間の境界のエネルギー差、すなわち領域Ｘにおける酸化還元反応の効果により、注入電荷輸送抑制層４４と光電変換層４３Ｂの界面近傍において、入射光により光電変換層４３Ｂ内に生成された電子正孔対の分離が促進される。図４においては、光電変換層４３ＢのＬＵＭＯ準位が注入電荷輸送抑制層４４のＬＵＭＯ準位に比較して小さいため、電子正孔対における電子がより安定した準位に落ち、正孔が陰極４５に輸送される。
結果として、光電変換層４３に注入電荷輸送抑制層４５を挿入した場合でも、有機光電変換膜の光電変換効率は低下せず、あるいは向上する。 On the other hand, since the thickness of the injected charge transport suppression layer 44 is smaller than that of the photoelectric conversion layers 43A and 43B, the partial pressure applied to the photoelectric conversion layers 43A and 43B suppresses the injection charge transport to the photoelectric conversion layers 43A and 43B. Compared to the case where the layer 44 is not inserted, an equivalent voltage is applied with almost no decrease.
Further, in addition to the separation effect of electron-hole pairs due to the electric field in the photoelectric conversion layers 43A and 43B, the energy difference at the boundary between the injected charge transport suppression layer 44 and the photoelectric conversion layer 43B, that is, the oxidation-reduction reaction in the region X The effect promotes the separation of electron-hole pairs generated in the photoelectric conversion layer 43B by incident light in the vicinity of the interface between the injected charge transport suppression layer 44 and the photoelectric conversion layer 43B. In FIG. 4, since the LUMO level of the photoelectric conversion layer 43B is smaller than the LUMO level of the injected charge transport suppression layer 44, the electrons in the electron-hole pairs fall to a more stable level, and the holes become the cathode. 45.
As a result, even when the injected charge transport suppression layer 45 is inserted into the photoelectric conversion layer 43, the photoelectric conversion efficiency of the organic photoelectric conversion film is not reduced or improved.

また、図５に示すように、光電変換層４４を形成する有機材料のＨＯＭＯ準位及びＬＵＭＯ準位各々に比較して、いずれも小さいＨＯＭＯ準位・ＬＵＭＯ準位を有し、かつ可視光領域の波長の光を透過する注入電荷輸送抑制層４４を、有機光電変換膜の光電変換層４３Ａ及び４３Ｂの間に、光電変換層４３Ａ及び光電変換層４３Ｂの厚さに比較して薄く挿入した場合も図４の構成と同様の効果が得られる。
この図５の構成として、光電変換層４３Ａ及び４３Ｂ内の電界による電子正孔対の分離効果に加え、光電変換層４３Ａと注入電荷輸送抑制層４４との間の境界のエネルギー差、すなわち領域Ｙにおける酸化還元反応の効果により、光電変換層４３Ａと注入電荷輸送抑制層４４との界面近傍において、入射光により光電変換層４３Ａ内に生成された電子正孔対の分離が促進される。図５においては、光電変換層４３ＡのＨＯＭＯ準位が注入電荷輸送抑制層４４のＨＯＭＯ準位に比較して大きいため、電子正孔対における正孔がより安定した準位に落ち、電子が陽極４１に輸送される。 In addition, as shown in FIG. 5, both the HOMO level and the LUMO level of the organic material forming the photoelectric conversion layer 44 are smaller than the HOMO level and the LUMO level, respectively, and have a visible light region. When the injected charge transport suppression layer 44 that transmits light of the wavelength of the light is inserted thinly between the photoelectric conversion layers 43A and 43B of the organic photoelectric conversion film as compared with the thickness of the photoelectric conversion layer 43A and the photoelectric conversion layer 43B The same effect as that of the configuration of FIG.
In the configuration of FIG. 5, in addition to the separation effect of electron-hole pairs due to the electric field in the photoelectric conversion layers 43A and 43B, the energy difference at the boundary between the photoelectric conversion layer 43A and the injected charge transport suppression layer 44, that is, the region Y Due to the effect of the redox reaction, separation of electron-hole pairs generated in the photoelectric conversion layer 43A by incident light is promoted in the vicinity of the interface between the photoelectric conversion layer 43A and the injected charge transport suppression layer 44. In FIG. 5, since the HOMO level of the photoelectric conversion layer 43A is larger than the HOMO level of the injected charge transport suppression layer 44, the holes in the electron-hole pair fall to a more stable level, and the electrons are anodes. 41 to be transported.

また、図６に示すように、光電変換層４３Ａ及び４３Ｂを形成する有機材料のＨＯＭＯ準位及びＬＵＭＯ準位各々に比較して、ＨＯＭＯ準位に比較して大きいＨＯＭＯ準位を有し、かつＬＵＭＯ準位に比較して小さいＬＵＭＯ準位を有し、さらに可視光領域の波長の光を透過する注入電荷輸送抑制層４４を有機光電変換膜の光電変換層４３Ａ及び４３Ｂの間に、光電変換層４３Ａ及び４３Ｂの厚さに比較して薄く挿入する構成としても良い。
この図６の構成の場合、注入電荷輸送抑制層４４と光電変換層４３Ａあるいは注入電荷輸送抑制層４３Ｂとの間の酸化還元反応が働かないため、すでに述べた構成に比較して電子正孔対の分離効率が低下し、光電変換効率は低下するが、一方、暗電流を大きく低減する効果がある。 Further, as shown in FIG. 6, the organic material forming the photoelectric conversion layers 43A and 43B has a HOMO level larger than the HOMO level compared to the HOMO level and the LUMO level of the organic material, and An injection charge transport suppressing layer 44 having a LUMO level smaller than the LUMO level and transmitting light having a wavelength in the visible light region is interposed between the photoelectric conversion layers 43A and 43B of the organic photoelectric conversion film. A configuration may be adopted in which the layers 43A and 43B are inserted thinner than the thickness of the layers 43A and 43B.
In the case of the configuration of FIG. 6, since the redox reaction between the injected charge transport suppression layer 44 and the photoelectric conversion layer 43A or the injected charge transport suppression layer 43B does not work, the electron-hole pair is compared with the configuration described above. However, there is an effect that the dark current is greatly reduced.

また、上述した有機光電変換素子を光センサの光電変換部とし、入射し吸収した光により発生した電荷（電子あるいは正孔）を読み出すため、この電荷読み出し手段としては、例えば、従来から用いられているＣＭＯＳ（Complimentary Metal Oxide Semiconductor）、あるいはＣＣＤ（Charge Coupled Device）、ＴＦＴ（Thin Film Transistor）などを用いた読出し回路を用いることが可能である。
ここで、図７のように上述した電荷読出し回路を２次元アレイ化し、入射光により生成された電荷を読み出す回路上に、特定の光の波長選択機能を有する有機光電変換素子を形成した、特定の波長の光を検出する単色固体撮像素子を形成することもできる。この際、有機光電変換素子は画素に区切らずともよい。 In addition, the above-described organic photoelectric conversion element is used as a photoelectric conversion unit of an optical sensor, and charges (electrons or holes) generated by incident and absorbed light are read out. A readout circuit using a CMOS (Complimentary Metal Oxide Semiconductor), a CCD (Charge Coupled Device), a TFT (Thin Film Transistor) or the like can be used.
Here, as shown in FIG. 7, the charge readout circuit described above is made into a two-dimensional array, and an organic photoelectric conversion element having a specific wavelength selection function is formed on the circuit that reads out the charge generated by incident light. It is also possible to form a monochromatic solid-state imaging device that detects light having a wavelength of. At this time, the organic photoelectric conversion element may not be divided into pixels.

また、上述した単色固体撮像素子について、Ｒ（赤色）の光の波長選択機能を有する第１の単色固体撮像素子と、Ｇ（緑色）の光の波長選択機能を有する第２の単色固体撮像素子及び、Ｂ（青色）の光の波長選択機能を有する第３の単色固体撮像素子を用意し、それぞれを順次積層したカラー固体撮像素子を形成することができる。１画素にて３色の輝度情報を取得することが可能で、かつ従来のようにプリズムや複数の固体撮像素子を設ける必要がないため、小型・軽量であり、かつ光の利用効率の高い高解像度なカラーカメラを実現できる。   In addition, with respect to the above-described monochromatic solid-state imaging device, a first monochromatic solid-state imaging device having a wavelength selection function for R (red) light and a second monochromatic solid-state imaging device having a wavelength selection function for G (green) light. In addition, it is possible to prepare a third solid-state solid-state image pickup device having a wavelength selection function of B (blue) light, and to form a color solid-state image pickup device in which each is sequentially laminated. It is possible to acquire luminance information of three colors with one pixel, and it is not necessary to provide a prism or a plurality of solid-state image sensors as in the prior art, so that it is small and lightweight and has high light utilization efficiency. A resolution color camera can be realized.

＜応用例１＞
図１における有機光電変換素子を、光電変換層４３Ａ及び４３Ｂの有機材料として、緑色の光に感度を有し、正孔輸送性を有するキナクリドン誘導体を用いた場合、このキナクリドン誘導体のＨＯＭＯ準位及びＬＵＭＯ準位各々に比較して、ＨＯＭＯ準位、ＬＵＭＯ準位それぞれが小さいトリフエニルアミン誘導体を注入電荷輸送抑制層４４に用いる構成として作成する。 <Application example 1>
When the organic photoelectric conversion element in FIG. 1 is a quinacridone derivative having a sensitivity to green light and having a hole transporting property as the organic material of the photoelectric conversion layers 43A and 43B, the HOMO level of the quinacridone derivative and A triphenylamine derivative having a smaller HOMO level and LUMO level than each LUMO level is used for the injection charge transport suppression layer 44.

応用例１における図１に示す有機光電変換素子の作製方法を以下に説明する。
洗浄したガラス基板上に陽極４１としてＩＴＯを３０ｎｍの厚さにて、スパッタ法により蒸着して形成する。
次に、上記ＩＴＯ上に、正孔注入阻止層４２としてアルミニウムキノリン(Ａｌｑ３)を３０ｎｍの厚さに抵抗加熱蒸着により形成する。
そして、上記正孔注入阻止層４２上に、光電変換層４３Ａとしてキナクリドン誘導体を５０ｎｍの厚さに抵抗加熱蒸着により形成する。 A method for manufacturing the organic photoelectric conversion element shown in FIG. 1 in Application Example 1 will be described below.
On the cleaned glass substrate, ITO is deposited as an anode 41 with a thickness of 30 nm by sputtering.
Next, aluminum quinoline (Alq3) is formed on the ITO as a hole injection blocking layer 42 to a thickness of 30 nm by resistance heating vapor deposition.
Then, a quinacridone derivative is formed as a photoelectric conversion layer 43A on the hole injection blocking layer 42 to a thickness of 50 nm by resistance heating vapor deposition.

この光電変換層４３Ａ上に、注入電荷輸送抑制層４４としてトリフエニルアミン誘導体を抵抗加熱蒸着により形成する。
次に、上記注入電荷輸送抑制層４４上に、光電変換層４３Ｂとしてキナクリドン誘導体を５０ｎｍの厚さに抵抗加熱蒸着により形成する。
ここで、上記正孔注入阻止層４２と、光電変換層４３Ａと、注入電荷輸送抑制層４４と、光電変換層４３Ｂとを連続して抵抗加熱蒸着した。
そして、上記光電変換層４３Ｂ上に、陽極４１の対向電極である陰極４５を、陽極４１と同様にスパッタ法により形成した。 On the photoelectric conversion layer 43A, a triphenylamine derivative is formed by resistance heating vapor deposition as the injected charge transport suppression layer 44.
Next, a quinacridone derivative is formed as a photoelectric conversion layer 43B on the injected charge transport suppression layer 44 to a thickness of 50 nm by resistance heating vapor deposition.
Here, the hole injection blocking layer 42, the photoelectric conversion layer 43A, the injected charge transport suppression layer 44, and the photoelectric conversion layer 43B were continuously deposited by resistance heating.
Then, a cathode 45 which is a counter electrode of the anode 41 was formed on the photoelectric conversion layer 43 </ b> B by the sputtering method in the same manner as the anode 41.

上記形成において、注入電荷輸送抑制層４４の厚さを複数の異なる厚さ、例えば０ｎｍ（注入電荷輸送抑制層４４を形成していない）、１ｎｍ、１０ｎｍ、２０ｎｍ、５０ｎｍ、１００ｎｍと変えた６つの試料を作製し、それぞれの電気特性の測定を行った。
上記６つの試料の測定結果として、設定された一定強度の入射光において、注入電荷輸送抑制層の厚さと、注入電荷輸送抑制層４４が０ｎｍの厚さにおける生成される電子正孔対による電流値を１とした相対信号電流値と、暗電流の実測値との対応を示すテーブルを図８に示す。 In the above formation, the thickness of the injection charge transport suppression layer 44 is changed to a plurality of different thicknesses, for example, 0 nm (the injection charge transport suppression layer 44 is not formed), 1 nm, 10 nm, 20 nm, 50 nm, and 100 nm. Samples were prepared and their electrical characteristics were measured.
As the measurement results of the above six samples, the thickness of the injected charge transport suppression layer and the current value due to the electron-hole pair generated when the injected charge transport suppression layer 44 is 0 nm in the set incident light of constant intensity. FIG. 8 shows a table showing the correspondence between the relative signal current value where 1 is 1 and the measured value of the dark current.

測定条件としては、陽極４１及び陰極４５の間に、２０Ｖの電圧を印加した状態にて、波長５５０ｎｍ、強度５０μＷ／ｃｍ２の光を入射した場合において、それぞれの試料の信号電流および暗電流を比較した。
ここで、信号電流値は上述したように、注入電荷輸送抑制層４４の厚さが０ｎｍの試料の信号電流値を１とした場合の相対電流値で表している。
注入電荷輸送抑制層４４の厚さが１ｎｍ〜５０ｎｍの各試料は、注入電荷輸送抑制層４４の厚さが０ｎｍの試料に比べて信号電流値が大きくなっており、特に注入電荷輸送抑制層４４の厚さが１０ｎｍの試料では１．５倍であった。 As measurement conditions, when a voltage of 20 V is applied between the anode 41 and the cathode 45 and light having a wavelength of 550 nm and an intensity of 50 μW / cm 2 is incident, the signal current and dark current of each sample are measured. Compared.
Here, as described above, the signal current value is expressed as a relative current value when the signal current value of a sample having a thickness of the injected charge transport suppression layer 44 of 0 nm is 1.
Each sample with the injection charge transport suppression layer 44 having a thickness of 1 nm to 50 nm has a larger signal current value than the sample with the injection charge transport suppression layer 44 having a thickness of 0 nm. Of the sample having a thickness of 10 nm was 1.5 times.

一方、暗電流値については、注入電荷輸送抑制層４４の厚さが厚くなるにつれて減少し、１００ｎｍの厚さにては測定限界を下回る数値まで減少している。
この結果から、注入電荷輸送抑制層４４を光電変換層４３Ａ及び４３Ｂの厚さに比較して薄い膜として、光電変換層４３Ａ及び４３Ｂの間に挿入することにより、暗電流を小さくし、従来例に対して光電変換効率が同等あるいは高い有機光電変換素子が得られることが確認できた。 On the other hand, the dark current value decreases as the thickness of the injected charge transport suppression layer 44 increases, and at a thickness of 100 nm, the dark current value decreases to a value below the measurement limit.
From this result, the injection current transport suppression layer 44 is made a thin film compared to the thickness of the photoelectric conversion layers 43A and 43B, and is inserted between the photoelectric conversion layers 43A and 43B, thereby reducing the dark current, and the conventional example. It was confirmed that an organic photoelectric conversion element having the same or high photoelectric conversion efficiency was obtained.

＜応用例２＞
応用例１と同様に緑色に感度を有するキナクリドン誘導体で形成された光電変換層の間に、キナクリドン誘導体のＨＯＭＯ準位及びＬＵＭＯ準位に比較して、ＨＯＭＯ準位、ＬＵＭＯ準位のいずれもが小さいエネルギー準位を有するトリフエニルアミン誘導体で形成された注入電荷輸送抑制層を複数層、例えば０層、２層、５層及び１０層有する４つの有機光電変換素子を作製した。
応用例２における図３（例えば、注入電荷輸送抑制層が２層に相当）に示す有機光電変換素子の作製方法を以下に説明する。 <Application example 2>
As in Application Example 1, between the photoelectric conversion layer formed of a quinacridone derivative having a sensitivity to green, both the HOMO level and the LUMO level are compared with the HOMO level and the LUMO level of the quinacridone derivative. Four organic photoelectric conversion elements having a plurality of injection charge transport suppression layers formed of a triphenylamine derivative having a small energy level, for example, 0 layer, 2 layers, 5 layers, and 10 layers, were produced.
A method for manufacturing the organic photoelectric conversion element shown in FIG. 3 in Application Example 2 (for example, the injection charge transport suppression layer corresponds to two layers) will be described below.

洗浄したガラス基板上に陽極４１としてＩＴＯを３０ｎｍの厚さにて、スパッタ法により蒸着して形成する。
次に、上記ＩＴＯ上に、正孔注入阻止層４２としてアルミニウムキノリン(Ａｌｑ３)を３０ｎｍの厚さに抵抗加熱蒸着により形成する。
そして、上記正孔注入阻止層４２上に、光電変換層４３Ａとしてキナクリドン誘導体を抵抗加熱蒸着により形成する。 On the cleaned glass substrate, ITO is deposited as an anode 41 with a thickness of 30 nm by sputtering.
Next, aluminum quinoline (Alq3) is formed on the ITO as a hole injection blocking layer 42 to a thickness of 30 nm by resistance heating vapor deposition.
Then, a quinacridone derivative is formed as the photoelectric conversion layer 43A on the hole injection blocking layer 42 by resistance heating vapor deposition.

この光電変換層４３Ａ上に、注入電荷輸送抑制層４４Ａとしてトリフエニルアミン誘導体を抵抗加熱蒸着により５ｎｍの厚さに形成する。
次に、上記注入電荷輸送抑制層４４Ａ上に、光電変換層４３Ｂとしてキナクリドン誘導体を抵抗加熱蒸着により形成する。
この光電変換層４３Ｂ上に、注入電荷輸送抑制層４４Ｂとしてトリフエニルアミン誘導体を抵抗加熱蒸着により５ｎｍの厚さに形成する。 On this photoelectric conversion layer 43A, a triphenylamine derivative is formed to a thickness of 5 nm by resistance heating vapor deposition as the injected charge transport suppression layer 44A.
Next, a quinacridone derivative is formed as a photoelectric conversion layer 43B on the injected charge transport suppression layer 44A by resistance heating vapor deposition.
On the photoelectric conversion layer 43B, a triphenylamine derivative is formed to a thickness of 5 nm by resistance heating vapor deposition as the injected charge transport suppression layer 44B.

そして、上記注入電荷輸送抑制層４４Ｂ上に、光電変換層４３Ｃとしてキナクリドン誘導体を抵抗加熱蒸着により形成する。
ここで、上記正孔注入阻止層４２と、光電変換層４３Ａと、注入電荷輸送抑制層４４Ａと、光電変換層４３Ｂ、注入電荷輸送抑制層４４Ｂと、光電変換層４３Ｃとを連続して抵抗加熱蒸着し、光電変換層（キナクリドン誘導体）は全体で１００ｎｍの厚さになるように形成した。
そして、上記光電変換層４３Ｃ上に、陽極４１の対向電極である陰極４５を、陽極４１と同様にスパッタ法により形成した。 Then, a quinacridone derivative is formed as the photoelectric conversion layer 43C on the injected charge transport suppression layer 44B by resistance heating vapor deposition.
Here, the hole injection blocking layer 42, the photoelectric conversion layer 43A, the injected charge transport suppression layer 44A, the photoelectric conversion layer 43B, the injected charge transport suppression layer 44B, and the photoelectric conversion layer 43C are continuously heated by resistance. The photoelectric conversion layer (quinacridone derivative) was formed so as to have a thickness of 100 nm as a whole.
Then, a cathode 45 that is a counter electrode of the anode 41 was formed on the photoelectric conversion layer 43 </ b> C by the sputtering method in the same manner as the anode 41.

上記形成において、光電変換層の間に介挿する注入電荷輸送抑制層の数を０層、２層、５層及び１０層の層数と変えた４つの試料を作製し、それぞれの電気特性の測定を行った。
上記光電変換層に介挿する各注入電荷輸送抑制層の１層あたりの厚さは、光電変換層中に注入電荷輸送抑制層を２層、５層及び１０層有する光電変換膜の場合、それぞれ５ｎｍ、 ２ｎｍ、１ｎｍの厚さとなるように形成し、さらに光電変換層中に注入電荷輸送抑制層を均等に挿入した。
上記４つの試料の測定結果として、設定された一定強度の入射光において、注入電荷輸送抑制層における注入電荷輸送抑制層の層の数と、注入電荷輸送抑制層４４が０層、すなわち挿入されていない場合に生成される電子正孔対による電流値を１とした相対信号電流値と、暗電流の実測値との対応を示すテーブルを図９に示す。 In the above formation, four samples were prepared by changing the number of injected charge transport suppression layers interposed between the photoelectric conversion layers to the number of layers 0, 2, 5, and 10 and the respective electric characteristics were Measurements were made.
The thickness per layer of each injected charge transport suppression layer interposed in the photoelectric conversion layer is, in the case of a photoelectric conversion film having 2 layers, 5 layers, and 10 layers of injected charge transport suppression layers in the photoelectric conversion layer, respectively. It formed so that it might become thickness of 5 nm, 2 nm, and 1 nm, and also the injection charge transport suppression layer was inserted in the photoelectric converting layer equally.
As the measurement results of the above four samples, in the incident light of the set constant intensity, the number of the injected charge transport suppressing layers in the injected charge transport suppressing layer and the injected charge transport suppressing layer 44 are zero, that is, inserted. FIG. 9 shows a table showing the correspondence between the relative signal current value where the current value due to the electron-hole pair generated when there is no electron current is 1 and the dark current measured value.

図９は陽極４１と陰極４５との間に２０Ｖの電圧を印加した状態において、波長５５０ｎｍ、強度５０μＷ/ｃｍ２の光を入射した場合、それぞれの試料の信号電流および暗電流を比較したものである。
ここで、上述したように、信号電流値は注入電荷輸送抑制層が０層、すなわち光電変換層に注入電荷輸送抑制層が介挿されていない試料における信号電流値を１とした相対電流値で表している。
光電変換層中に注入電荷輸送抑制層を２層及び５層有する試料は、注入電荷輸送抑制層が挿入されていない試料に比較して、信号電流値が大きくなっている。
一方、暗電流値は、注入電荷輸送抑制層の数が増えるに従って減少している。この結果から、複数の注入電荷輸送抑制層を光電変換層に薄く挿入する場合において、暗電流が小さく光電変換効率が従来例と同等あるいは高い有機光電変換素子が得られるという本発明の効果が確認できた。 FIG. 9 compares the signal current and dark current of each sample when light having a wavelength of 550 nm and an intensity of 50 μW / cm 2 is incident with a voltage of 20 V applied between the anode 41 and the cathode 45. is there.
Here, as described above, the signal current value is a relative current value in which the injected current transport suppression layer is 0 layer, that is, the signal current value is 1 in the sample in which the injected charge transport suppression layer is not inserted in the photoelectric conversion layer. Represents.
A sample having two and five injected charge transport suppression layers in the photoelectric conversion layer has a larger signal current value than a sample in which the injected charge transport suppression layer is not inserted.
On the other hand, the dark current value decreases as the number of injected charge transport suppression layers increases. This result confirms the effect of the present invention that an organic photoelectric conversion element with a low dark current and a photoelectric conversion efficiency equal to or higher than that of the conventional example can be obtained when a plurality of injected charge transport suppression layers are inserted thinly into the photoelectric conversion layer. did it.

＜応用例３＞
図１における有機光電変換素子を、光電変換層４３Ａ及び４３Ｂの有機材料として、青色の光に感度を有し、正孔輸送性を有するポルフィリン誘導体を用いた場合、このポルフィリン誘導体のＨＯＭＯ準位及びＬＵＭＯ準位各々に比較して、ＨＯＭＯ準位、ＬＵＭＯ準位がそれぞれ大きいＡ１錯体（アルミニウムキノリン）を注入電荷輸送抑制層４４に用いる構成として作製する。 <Application example 3>
When the porphyrin derivative having sensitivity to blue light and hole transportability is used as the organic material of the photoelectric conversion layers 43A and 43B in the organic photoelectric conversion element in FIG. 1, the HOMO level of the porphyrin derivative and An A1 complex (aluminum quinoline) having a larger HOMO level and LUMO level than each LUMO level is used for the injection charge transport suppression layer 44.

応用例３における図１に示す有機光電変換素子の作製方法を以下に説明する。
洗浄したガラス基板上に陽極４１としてＩＴＯを３０ｎｍの厚さにて、スパッタ法により蒸着して形成する。
次に、上記ＩＴＯ上に、正孔注入阻止層４２としてアルミニウムキノリン(Alq3)を３０ｎｍの厚さに抵抗加熱蒸着により形成する。
そして、上記正孔注入阻止層４２上に光電変換層４３Ａとしてポルフィリン誘導体を４０ｎｍの厚さに抵抗加熱蒸着により形成する。 A method for manufacturing the organic photoelectric conversion element shown in FIG. 1 in Application Example 3 will be described below.
On the cleaned glass substrate, ITO is deposited as an anode 41 with a thickness of 30 nm by sputtering.
Next, aluminum quinoline (Alq3) is formed on the ITO as a hole injection blocking layer 42 by resistance heating vapor deposition to a thickness of 30 nm.
Then, a porphyrin derivative is formed as a photoelectric conversion layer 43A on the hole injection blocking layer 42 to a thickness of 40 nm by resistance heating vapor deposition.

この光電変換層４３Ａ上に、注入電荷輸送抑制層４４として正孔注入阻止層４２と同じアルミニウムキノリンを１０ｎｍの厚さに抵抗加熱蒸着により形成する。
次に、上記注入電荷輸送抑制層４４上に、光電変換層４３Ｂとしてポルフィリン誘導体を４０ｎｍの厚さに抵抗加熱蒸着により形成する。
ここで、上記正孔注入阻止層４２と、光電変換層４３Ａと、注入電荷輸送抑制層４４と、光電変換層４３Ｂとを連続して抵抗加熱蒸着した。
そして、上記光電変換層４３Ｂ上に、陽極４１の対向電極である陰極４５を、陽極４１と同様にスパッタ法により形成した。 On the photoelectric conversion layer 43A, the same aluminum quinoline as the hole injection blocking layer 42 is formed as an injected charge transport suppressing layer 44 by resistance heating vapor deposition to a thickness of 10 nm.
Next, a porphyrin derivative is formed as a photoelectric conversion layer 43B on the injected charge transport suppression layer 44 to a thickness of 40 nm by resistance heating vapor deposition.
Here, the hole injection blocking layer 42, the photoelectric conversion layer 43A, the injected charge transport suppression layer 44, and the photoelectric conversion layer 43B were continuously deposited by resistance heating.
Then, a cathode 45 which is a counter electrode of the anode 41 was formed on the photoelectric conversion layer 43 </ b> B by the sputtering method in the same manner as the anode 41.

上記形成において、注入電荷輸送抑制層４４を有無とした２つの試料を作製し、それぞれの電気特性の測定を行った。
上記の試料の測定結果として、設定された一定強度の入射光において、注入電荷輸送抑制層の有無と、注入電荷輸送抑制層４４がない試料における生成される電子正孔対による電流値を１とした相対信号電流値と、暗電流の実測値との対応を示すテーブルを図１０に示す。 In the above formation, two samples with and without the injected charge transport suppression layer 44 were prepared, and their electrical characteristics were measured.
As the measurement result of the above sample, in the incident light of the set constant intensity, the presence / absence of the injected charge transport suppression layer and the current value due to the electron-hole pair generated in the sample without the injected charge transport suppression layer 44 are 1. FIG. 10 shows a table showing the correspondence between the measured relative signal current values and the measured dark current values.

測定条件としては、陽極４１及び陰極４５の間に、２５Ｖの電圧を印加した状態にて、波長４８０ｎｍ、強度５０μＷ／ｃｍ２の光を入射した場合においてそれぞれの試料の信号電流及び暗電流を比較した。
ここで、信号電流値は上述したように注入電荷輸送抑制層４４がない試料の信号値を１とした場合の相対電流値で表している。
注入電荷輸送抑制層４４が有る場合の試料は無い場合の試料に比べて信号電流値が約１割５分大きくなった。 As measurement conditions, when a voltage of 25 V is applied between the anode 41 and the cathode 45 and light having a wavelength of 480 nm and an intensity of 50 μW / cm 2 is incident, the signal current and dark current of each sample are compared. did.
Here, the signal current value is expressed as a relative current value when the signal value of the sample without the injected charge transport suppression layer 44 is 1, as described above.
The signal current value was increased by about 15% compared to the sample without the sample with the injected charge transport suppression layer 44.

一方、暗電流については、注入電荷輸送抑制層４４を入れることによって小さくなっている。
この結果から、注入電荷輸送抑制層４４を光電変換層４３Ａ及び４３Ｂの厚さに比較して薄い膜として、光電変換層４３Ａ及び４３Ｂの間に挿入することにより、暗電流を小さくし、従来例に対して光電変換効率が同等あるいは高い有機光電変換素子が得られることが確認できた。 On the other hand, the dark current is reduced by inserting the injected charge transport suppression layer 44.
From this result, the injection current transport suppression layer 44 is made a thin film compared to the thickness of the photoelectric conversion layers 43A and 43B, and is inserted between the photoelectric conversion layers 43A and 43B, thereby reducing the dark current, and the conventional example. It was confirmed that an organic photoelectric conversion element having the same or high photoelectric conversion efficiency was obtained.

＜応用例４＞
図１における有機光電変換素子を、光電変換層４３Ａ及び４３Ｂの有料材料として、赤色の光に感度を有し、正孔輸送性を有する亜鉛フタロシアニンを用いた場合、この亜鉛フタロシアニンのＨＯＭＯ準位及びＬＵＭＯ準位各々に比較して、ＨＯＭＯ準位に比較して大きいＨＯＭＯ準位有し、かつＬＵＭＯ準位に比較して小さいＬＵＭＯ準位を有するトリフェニルアミン誘導体を注入電荷輸送抑制層４４に用いる構成として作製する。 <Application Example 4>
In the case where the organic photoelectric conversion element in FIG. 1 is made of zinc phthalocyanine having sensitivity to red light and having hole transportability as a chargeable material for the photoelectric conversion layers 43A and 43B, the HOMO level of this zinc phthalocyanine and A triphenylamine derivative having a larger HOMO level than the HOMO level compared to each LUMO level and a smaller LUMO level than the LUMO level is used for the injection charge transport suppression layer 44. It is produced as a configuration.

上記応用例４における図１に示す有機光電変換素子の作製方法を以下に説明する。
洗浄したガラス基板上に陽極４１としてＩＴＯを３０ｎｍの厚さにて、スパッタ法により蒸着して形成する。
次に、上記ＩＴＯ上に正孔注入阻止層４２としてアルミニウムキノリン(Alq3)を３０ｎｍの厚さに抵抗加熱蒸着により形成する。
そして、上記正孔注入阻止層４２上に光電変換層４３Ａとして亜鉛フタロシアニンを５０ｎｍの厚さに抵抗加熱蒸着により形成する。 A method for manufacturing the organic photoelectric conversion element shown in FIG. 1 in Application Example 4 will be described below.
On the cleaned glass substrate, ITO is deposited as an anode 41 with a thickness of 30 nm by sputtering.
Next, aluminum quinoline (Alq3) is formed on the ITO as a hole injection blocking layer 42 to a thickness of 30 nm by resistance heating vapor deposition.
Then, zinc phthalocyanine is formed as a photoelectric conversion layer 43A on the hole injection blocking layer 42 to a thickness of 50 nm by resistance heating vapor deposition.

この光電変換層４３Ａ上に、注入電荷輸送抑制層４４としてトリフェニルアミン誘導体を１０ｎｍの厚さに抵抗加熱蒸着により形成する。
次に、上記注入電荷輸送抑制層４４上に、光電変換層４３Ｂとして亜鉛フタロシアニンを５０ｎｍの厚さに抵抗加熱蒸着により形成する。
ここで、上記正孔注入阻止層４２と光電変換層４３Ａと、注入電荷輸送抑制層４４と、光電変換層４３Ｂとを連続して抵抗加熱蒸着した。
そして、上記光電変換層４３Ｂ上に、陽極４１の対向電極である陰極４５を、陽極４１と同様にスタッパ法により形成した。 On this photoelectric conversion layer 43A, a triphenylamine derivative is formed to a thickness of 10 nm by resistance heating vapor deposition as the injected charge transport suppression layer 44.
Next, zinc phthalocyanine is formed as a photoelectric conversion layer 43B on the injected charge transport suppression layer 44 to a thickness of 50 nm by resistance heating vapor deposition.
Here, the hole injection blocking layer 42, the photoelectric conversion layer 43A, the injected charge transport suppression layer 44, and the photoelectric conversion layer 43B were continuously deposited by resistance heating.
Then, on the photoelectric conversion layer 43 </ b> B, a cathode 45 that is a counter electrode of the anode 41 was formed by the stapper method similarly to the anode 41.

上記形成において、注入電荷輸送抑制層４４を有無とした２つの試料を作製し、それぞれの電気特性の測定を行った。
上記の試料の測定結果として、設定された一定強度の入射光において、注入電荷輸送抑制層の有無と、注入電荷輸送抑制層４４がない試料における生成される電子正孔対による電流値を１とした相対信号電流値と、暗電流の実測値との対応を示すテーブルを図１１に示す。 In the above formation, two samples with and without the injected charge transport suppression layer 44 were prepared, and their electrical characteristics were measured.
As the measurement result of the above sample, in the incident light of the set constant intensity, the presence / absence of the injected charge transport suppression layer and the current value due to the electron-hole pair generated in the sample without the injected charge transport suppression layer 44 are 1. FIG. 11 shows a table showing the correspondence between the relative signal current values and the dark current measured values.

測定条件としては、陽極４１及び陰極４５の間に、３０Ｖの電圧を印加した状態にて、波長６５０ｎｍ、強度５０μＷ／ｃｍ２の光を入射した場合において、それぞれの試料の信号電流及び暗電流を比較した。
ここで、信号電流値は上述したように注入電荷輸送抑制層４４がない試料の信号電流値を１とした相対電流値で表している。
注入電荷輸送抑制層４４を入れることで信号電流値は約３割減少した。 As measurement conditions, when a voltage of 30 V is applied between the anode 41 and the cathode 45 and light having a wavelength of 650 nm and an intensity of 50 μW / cm 2 is incident, the signal current and dark current of each sample are measured. Compared.
Here, as described above, the signal current value is expressed as a relative current value where the signal current value of the sample without the injected charge transport suppression layer 44 is 1.
By inserting the injection charge transport suppression layer 44, the signal current value was reduced by about 30%.

一方、暗電流については、注入電荷輸送抑制層４４を入れることによって小さくなっている。
この結果から、光電変換層４３Ａ及び４３ＢのＨＯＭＯ準位に比較して大きいＨＯＭＯ準位を有し、かつＬＵＭＯ準位に比較して小さいＬＵＭＯ準位を有する注入電荷輸送抑制層４４を光電変換層４３Ａ及び４３Ｂの厚さに比較して薄い膜として、光電変換層４３Ａ及び４３Ｂの間に挿入することにより、暗電流の小さい有機光電変換素子が得られることが確認できた。 On the other hand, the dark current is reduced by inserting the injected charge transport suppression layer 44.
From this result, the injection charge transport suppression layer 44 having a large HOMO level compared to the HOMO levels of the photoelectric conversion layers 43A and 43B and a small LUMO level compared to the LUMO level is obtained as a photoelectric conversion layer. It was confirmed that an organic photoelectric conversion element with a small dark current can be obtained by inserting it between the photoelectric conversion layers 43A and 43B as a thin film compared to the thickness of 43A and 43B.

（実施の形態２）
図７に示されるように、応用例１記載の有機光電変換素子を２次元アレイ化された読出し回路上に形成し、単色固体撮像素子を作製した。形成方法は応用例１と同様である。
ここで読み出し回路は、従来から用いられているＭＯＳトランジスタによるスイッチング回路を用いることができる。例えば、特開２００６−８６４９３の図４の例を適用できる。すなわち、図７の有機光電変換素子の上側を光入射方向とした場合、光入射方向の電極は全画素共通の透明電極とし、読み出し回路側は画素毎に設けられた電極として、電極間に電圧を印加することにより、電極と電極との間に生じる電界によって入射光により光導電層で生じた電荷が電極まで達し、さらに読み出し回路のＭＯＳトランジスタの電荷蓄積部まで移動して、電荷蓄積部に電荷が蓄積される。電荷蓄積部の電荷はＭＯＳトランジスタのスイッチングにより２次元的に読み出され、電気信号として出力されるものである。
有機光電変換素子として応用例３の有機材料を用いれば青色、応用例１ならば緑色、応用例４ならば赤色をそれぞれ吸収する分光感度に対応した光センサとできる。 (Embodiment 2)
As shown in FIG. 7, the organic photoelectric conversion element described in Application Example 1 was formed on a two-dimensional arrayed readout circuit to produce a monochromatic solid-state imaging element. The formation method is the same as in Application Example 1.
Here, a conventional switching circuit using a MOS transistor can be used as the readout circuit. For example, the example of FIG. 4 of Unexamined-Japanese-Patent No. 2006-86493 is applicable. That is, when the upper side of the organic photoelectric conversion element in FIG. 7 is the light incident direction, the electrode in the light incident direction is a transparent electrode common to all pixels, and the readout circuit side is an electrode provided for each pixel. Is applied, the charge generated in the photoconductive layer by the incident light due to the electric field generated between the electrodes reaches the electrode, and further moves to the charge storage portion of the MOS transistor of the readout circuit, and enters the charge storage portion. Charge is accumulated. The charge in the charge storage unit is read out two-dimensionally by switching of the MOS transistor and output as an electric signal.
If the organic material of the application example 3 is used as an organic photoelectric conversion element, it can be set as the optical sensor corresponding to the spectral sensitivity which absorbs blue, the application example 1 is green, and the application example 4 is red.

（実施の形態３）
青色用有機光電変換素子、緑色用有機光電変換素子、赤色用有機光電変換素子を積層し、さらに２次元読み出し回路を設ければカラー撮像素子を形成できる。
この場合、例えば図１２に示す特開２００６−８６４９３の例のように、青色用有機光電変換素子１２３、緑色用有機光電変換素子１１８、赤色用有機光電変換素子１１３の各有機光電変換素子の間はそれぞれ透明絶縁膜１２０、１１５により絶縁され、また赤色用有機光電変換素子１１３と、読み出し回路１００との間は絶縁膜１１０及び１１９により絶縁されている。光入射側の電極１２５は透明で全画素共通であり、光入射側でない方の電極は各画素毎の透明のモザイク状電極である（最下側は透明でなくてもよい）。ここで、各有機光電変換素子は透明電極間にＲ、Ｇ、Ｂそれぞれの色に対応した波長選択機能を有する有機光電変換材料の薄膜を有する本実施形態の構成となる素子である。
モザイク状の各画素毎の電極はＭＯＳトランジスタの電荷蓄積部１０２と配線１２２により電気的に接続されており、これらは途中にある有機光電変換素子とは絶縁されている。電圧が印加されて光電変換層で発生した電荷は電極に到達し、ＭＯＳトランジスタの電荷蓄積部１０２に蓄積される。これが２次元的に読み出されるので、各有機光電変換素子毎の電荷に対応した電気信号は独立に処理可能であり、従って、図１２の構成に対して、本発明の光電変換素子を適用することにより、容易にカラー撮像素子を構成できる。 (Embodiment 3)
If a blue organic photoelectric conversion element, a green organic photoelectric conversion element, and a red organic photoelectric conversion element are stacked, and a two-dimensional readout circuit is provided, a color imaging element can be formed.
In this case, for example, as in the example of Japanese Patent Application Laid-Open No. 2006-86493 shown in FIG. 12, between the organic photoelectric conversion elements of the blue organic photoelectric conversion element 123, the green organic photoelectric conversion element 118, and the red organic photoelectric conversion element 113. Are insulated by transparent insulating films 120 and 115, respectively, and the organic photoelectric conversion element for red 113 and the readout circuit 100 are insulated by insulating films 110 and 119. The electrode 125 on the light incident side is transparent and common to all pixels, and the electrode not on the light incident side is a transparent mosaic electrode for each pixel (the lowermost side does not have to be transparent). Here, each organic photoelectric conversion element is an element having the configuration of this embodiment having a thin film of an organic photoelectric conversion material having a wavelength selection function corresponding to each color of R, G, and B between transparent electrodes.
The electrodes for each pixel in a mosaic shape are electrically connected to the charge storage portion 102 of the MOS transistor and the wiring 122, and these are insulated from the organic photoelectric conversion element in the middle. The charge generated in the photoelectric conversion layer by applying the voltage reaches the electrode and is accumulated in the charge accumulation unit 102 of the MOS transistor. Since this is read out two-dimensionally, the electric signal corresponding to the electric charge for each organic photoelectric conversion element can be processed independently. Therefore, the photoelectric conversion element of the present invention is applied to the configuration of FIG. Thus, a color image sensor can be easily configured.

あるいは、特開２００５−５１１１５の図５の積層型撮像素子のように、複数の薄膜トランジスタアレイと、複数の受光部が積層された構造により、カラー撮像素子を構成できる。
ここで、各受光部は、Ｒ、Ｇ、Ｂのそれぞれの色に対応した波長選択機能を有する有機光電変換材料の薄膜を有する本発明の有機光電変換素子により構成することができる。
上述したカラー撮像素子において、電圧が印加されたＲ、Ｇ、Ｂの各受光部から、受光により発生した電荷がそれぞれ対応する薄膜トランジスタの電極に到達する。これら電荷が各受光部から薄膜トランジスタにより２次元的に読み出され、各薄膜トランジスタアレイからＲ、Ｇ、Ｂに対応した電気信号が得られる。従って、上述した構造によりカラー撮像素子が構成できる。 Alternatively, a color imaging device can be configured by a structure in which a plurality of thin film transistor arrays and a plurality of light receiving portions are stacked as in the stacked imaging device in FIG. 5 of JP-A-2005-51115.
Here, each light-receiving part can be comprised by the organic photoelectric conversion element of this invention which has a thin film of the organic photoelectric conversion material which has a wavelength selection function corresponding to each color of R, G, B.
In the color image sensor described above, the charges generated by light reception from the R, G, and B light receiving portions to which voltage is applied respectively reach the corresponding thin film transistor electrodes. These charges are two-dimensionally read out from each light receiving portion by a thin film transistor, and electrical signals corresponding to R, G, and B are obtained from each thin film transistor array. Therefore, a color image sensor can be configured with the above-described structure.

上述したように、本発明においては、光電変換層に用いられる有機材料に比べてＨＯＭＯ準位・ＬＵＭＯ準位がいずれも大きくあるいはいずれも小さく、なおかつ可視光領域の光を透過し、さらに電荷輸送性を有する有機材料で形成された注入電荷輸送抑制層を、光電変換層の中に０．５ｎｍ〜５０ｎｍの厚さにて１層あるいは複数層を挿入している。
本発明は、上記構成により、従来例に比較して、光電変換層と、この光電変換層の間に挿入した注入電荷輸送抑制層とのエネルギー準位差によって、陽極４１及び陰極４５から注入される電荷（正孔及び電子）の移動が抑制されるため暗電流が小さく、また上記エネルギー準位差による酸化還元反応により電子正孔対の分離が促進され、光電変換効率の高い有機光電変換素子が得られる。 As described above, in the present invention, the HOMO level and the LUMO level are both larger or smaller than the organic material used for the photoelectric conversion layer, transmits light in the visible light region, and further transports charges. One layer or a plurality of layers are inserted into the photoelectric conversion layer with a thickness of 0.5 nm to 50 nm as an injection charge transport suppression layer formed of an organic material having a property.
According to the above configuration, the present invention is injected from the anode 41 and the cathode 45 by the energy level difference between the photoelectric conversion layer and the injected charge transport suppression layer inserted between the photoelectric conversion layers as compared with the conventional example. Organic photoelectric conversion element with high photoelectric conversion efficiency due to the suppression of the movement of the charge (holes and electrons), the dark current is small, and the redox reaction due to the energy level difference promotes the separation of electron-hole pairs Is obtained.

本発明の実施形態による有機光電変換素子の断面構造を示す概念図である。It is a conceptual diagram which shows the cross-section of the organic photoelectric conversion element by embodiment of this invention. 図１に示す断面構造の有機光電変素子の電圧を印加しないときの各層のエネルギーダイアグラム（エネルギー準位図）を示す図であるIt is a figure which shows the energy diagram (energy level diagram) of each layer when not applying the voltage of the organic photoelectric conversion element of the cross-sectional structure shown in FIG. 本発明の実施形態による他の有機光電変換素子の断面構造を示す概念図である。It is a conceptual diagram which shows the cross-sectional structure of the other organic photoelectric conversion element by embodiment of this invention. 図１に示す構造の有機光電変換素子の電圧印加時のエネルギーダイアグラム（エネルギー準位図）の一例である。It is an example of the energy diagram (energy level diagram) at the time of the voltage application of the organic photoelectric conversion element of the structure shown in FIG. 図１に示す構造の他の有機光電変換素子の電圧印加時のエネルギーダイアグラム（エネルギー準位図）の例である。It is an example of the energy diagram (energy level diagram) at the time of the voltage application of the other organic photoelectric conversion element of the structure shown in FIG. 図１に示す構造の他の有機光電変換素子の電圧印加時のエネルギーダイアグラム（エネルギー準位図）の例である。It is an example of the energy diagram (energy level diagram) at the time of the voltage application of the other organic photoelectric conversion element of the structure shown in FIG. 入射光により生成された電荷を読み出す回路と、特定の光の波長選択機能を有する有機光電変換素子とを重ね合わせた単色固体撮像素子の概念図である。It is a conceptual diagram of a monochromatic solid-state imaging device in which a circuit for reading out charges generated by incident light and an organic photoelectric conversion device having a specific light wavelength selection function are superimposed. 図１の構造の有機光電変換膜において、注入電荷輸送抑制層の厚さの異なった試料の測定結果を示すテーブルである。3 is a table showing measurement results of samples having different thicknesses of injected charge transport suppression layers in the organic photoelectric conversion film having the structure of FIG. 1. 図１の構造の有機光電変換膜において、光電変換層に介挿する注入電荷輸送抑制層の数を異ならせた試料の測定結果を示すテーブルである。2 is a table showing measurement results of samples with different numbers of injected charge transport suppression layers interposed in the photoelectric conversion layer in the organic photoelectric conversion film having the structure of FIG. 1. 図１の断面構造を有する有機光電変換膜における注入電荷輸送抑制層の有無の試料測定結果を示すテーブルである。It is a table | surface which shows the sample measurement result of the presence or absence of the injection charge transport suppression layer in the organic photoelectric conversion film which has the cross-sectional structure of FIG. 図１の断面構造を有する有機光電変換膜における注入電荷輸送抑制層の有無の試料測定結果を示すテーブルである。It is a table | surface which shows the sample measurement result of the presence or absence of the injection charge transport suppression layer in the organic photoelectric conversion film which has the cross-sectional structure of FIG. 本実施形態による誘起光電変換素子を用いたカラー撮像素子の断面構造を示す図である。It is a figure which shows the cross-section of the color image pick-up element using the induced photoelectric conversion element by this embodiment. 従来の有機光電変換素子の断面構造を示す概念図である。It is a conceptual diagram which shows the cross-section of the conventional organic photoelectric conversion element. 従来の有機光電変換膜の電圧を印加しないときのエネルギーダイアグラムの一例である。It is an example of the energy diagram when not applying the voltage of the conventional organic photoelectric conversion film. 従来の有機光電変換膜に電圧を印加した状態のエネルギーダイアグラムの他の例である。It is another example of the energy diagram of the state which applied the voltage to the conventional organic photoelectric converting film. 従来の有機光電変換膜に電圧を印加した状態のエネルギーダイアグラムの他の例である。It is another example of the energy diagram of the state which applied the voltage to the conventional organic photoelectric converting film.

符号の説明Explanation of symbols

４１…陽極
４２…正孔
４３Ａ，４３Ｂ，４３Ｃ…光電変換層
４４，４４Ａ，４４Ｂ…注入電荷輸送抑制層
４５…陰極 DESCRIPTION OF SYMBOLS 41 ... Anode 42 ... Hole 43A, 43B, 43C ... Photoelectric conversion layer 44, 44A, 44B ... Injection charge transport suppression layer 45 ... Cathode

Claims (6)

陽極と、陰極と、これら電極間に介挿された有機半導体層からなる有機光電変換素子であって、
前記有機半導体層が、
光電変換層と、
この光電変換層の間に形成された可視光領域の光を透過する有機材料からなる注入電荷輸送抑制層と
から構成され、
前記注入電荷輸送抑制層のＨＯＭＯ準位・ＬＵＭＯ準位が、光電変換層に用いられている有機材料のＨＯＭＯ準位・ＬＵＭＯ準位に比較し、いずれも大きい、またはいずれも小さい有機材料にて形成されていることを特徴とする有機光電変換素子。 An organic photoelectric conversion element comprising an anode, a cathode, and an organic semiconductor layer interposed between these electrodes,
The organic semiconductor layer is
A photoelectric conversion layer;
An injection charge transport suppression layer made of an organic material that transmits light in the visible light region formed between the photoelectric conversion layers, and
The HOMO level / LUMO level of the injection charge transport suppression layer is larger or smaller than the HOMO level / LUMO level of the organic material used for the photoelectric conversion layer. An organic photoelectric conversion element formed. 前記光電変換層が特定の波長の光のみを吸収し、該光を光電変換する波長選択機能を有する有機材料で形成されていることを特徴とする請求項１に記載の有機光電変換素子。   The organic photoelectric conversion element according to claim 1, wherein the photoelectric conversion layer is formed of an organic material having a wavelength selection function of absorbing only light of a specific wavelength and photoelectrically converting the light. 前記注入電荷輸送抑制層が０．５ｎｍ〜５０ｎｍの厚さで構成されていることを特徴とする請求項１または請求項２に記載の有機光電変換素子。   The organic photoelectric conversion device according to claim 1, wherein the injection charge transport suppression layer is formed with a thickness of 0.5 nm to 50 nm. 前記注入電荷輸送抑制層が前記光電変換層に１層あるいは複数層介挿されていることを特徴とする請求項１から請求項３のいずれかに記載の有機光電変換素子。   The organic photoelectric conversion element according to any one of claims 1 to 3, wherein the injection charge transport suppression layer is interposed in the photoelectric conversion layer by one layer or a plurality of layers. 請求項１から請求項４のいずれかの有機光電変換素子と、入射光により生成された電荷を読み出す読み出し回路を備えた光センサ。   An optical sensor comprising the organic photoelectric conversion element according to any one of claims 1 to 4 and a readout circuit for reading out charges generated by incident light. 請求項１から請求項４のいずれかの有機光電変換素子のなかで、青色に波長選択機能を有する有機光電変換素子と、緑色に波長選択機能を有する有機光電変換素子と、赤色に波長選択機能を有する有機光電変換素子と、前記各有機光電変換素子で生じた電荷を読み出す読み出し回路を順次積層したカラー撮像素子。   Among the organic photoelectric conversion elements according to any one of claims 1 to 4, an organic photoelectric conversion element having a wavelength selection function in blue, an organic photoelectric conversion element having a wavelength selection function in green, and a wavelength selection function in red A color image pickup device in which an organic photoelectric conversion device having a reading circuit and a readout circuit for reading out electric charges generated in each organic photoelectric conversion device are sequentially stacked.
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