CN109920939B

CN109920939B - Solvent, method and application for preparing high-performance metal halide perovskite film

Info

Publication number: CN109920939B
Application number: CN201910103268.0A
Authority: CN
Inventors: 王瑞瑶; 闫天昊
Original assignee: Xian Jiaotong Liverpool University
Current assignee: Xian Jiaotong Liverpool University
Priority date: 2019-02-01
Filing date: 2019-02-01
Publication date: 2022-03-29
Anticipated expiration: 2039-02-01
Also published as: CN109920939A

Abstract

A solvent, a method and an application for preparing a high-performance metal halide perovskite film belong to the technical field of microelectronics. The solvent for preparing the high-performance metal halide perovskite thin film comprises 3 parts of DMF (dimethyl formamide) and 1-2 parts of GBL (GBL) in parts by volume. The invention can effectively regulate and control the appearance of the perovskite film and improve the performance, efficiency and stability of the device; the method is used for industrial production and has the characteristics of simple and easy operation, low cost, strong controllability and the like.

Description

Solvent, method and application for preparing high-performance metal halide perovskite film

Technical Field

The invention relates to a technology in the field of microelectronics, in particular to a solvent, a method and application for preparing a high-performance metal halide perovskite thin film.

Background

In recent years, metal halide perovskite thin films have attracted wide attention worldwide due to their advantages of excellent photoelectric properties, low cost, simple preparation process, and the like. From the initial three-dimensional perovskite structure to the present, the perovskite material is also expanded from the solar cell to various aspects such as laser emitters, light emitting diodes, thermoelectric devices, photodetectors and the like. The perovskite thin film based device not only has high performance, but also has low cost and simple and convenient production and processing technology, thereby having the potential of large-scale industrialization.

Although perovskite devices are being fabricated and performance developed rapidly, thin film quality remains the most important limiting factor in device performance and reliability. In order to obtain high-performance perovskite devices, many effective perovskite thin film preparation processes and methods are discovered in recent years on the basis of a one-step solution method, including a two-step solution method, an anti-solvent rapid crystallization method, a solution method + a gas phase method, a vacuum dual-source gas phase synthesis method and the like. The one-step solution process is simple, but the quality of the prepared perovskite thin film is general, while other methods do improve the quality and the repeatability of the perovskite thin film, but the process is complex, so that the production cost is greatly improved, and the development and the commercialization of perovskite devices are not facilitated.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a solvent, a method and application for preparing a high-performance metal halide perovskite thin film.

The invention is realized by the following technical scheme:

the invention relates to a solvent for preparing a high-performance metal halide perovskite thin film, which comprises 3 parts of DMF (dimethyl formamide) and 1-2 parts of GBL (GBL) in parts by volume.

Preferably, the volume ratio of DMF to GBL is 6.5: 3.5.

The invention relates to a method for preparing a high-performance metal halide perovskite film, which comprises the following steps:

S₁preparing a perovskite precursor solution:

at least one raw material AX and at least one raw material BY are mixed₂Adding the mixture into the solvent, and stirring at room temperature or under heating to prepare a precursor solution of the metal halide perovskite;

S₂preparing a perovskite thin film:

in a glove box or in the air, step S is carried out by spin coating or printing₁The prepared metal halide perovskite precursor solution is uniformly loaded on a substrate, and is heated, annealed and cooled to room temperature after crystallization, so that the high-performance metal halide perovskite film is obtained.

The radical A in the starting material AX is a monovalent radical selected from the group consisting of NH₂-CH＝NH₂ ⁺、R₁NH₃ ⁺And a monovalent metal cation; x is a monovalent anion selected from the group consisting of I^-、Br^-、Cl^-、SCN^-、NCS^-、NO₃ ^-、R₂COO^-Any one of them; r₁And R₂Respectively any one of alkane, alkene, alkyne or aromatic hydrocarbon group.

Raw material BY₂Wherein B is a positive divalent metal cation; y is a monovalent anion selected from the group consisting of I^-、Br^-、Cl^-、SCN^-、NCS^-、NO₃ ^-、R₃COO^-Any one of them; r₃Is any one of alkane, alkene, alkyne or aromatic hydrocarbon group.

The heating and annealing are carried out by heating techniques such as a heating plate, baking in an oven, hot air flow, microwave and the like under normal pressure or reduced pressure.

The annealing temperature is 50-150 ℃, and the annealing time is 0.5-100 min.

The substrate is any flexible or rigid substrate, preferably a conductive substrate.

The invention relates to a high-performance metal halide perovskite thin film which is prepared by adopting the method.

Technical effects

Compared with the prior art, the invention has the following technical effects:

1) the perovskite precursor solution is prepared by using a DMF-GBL mixed solvent, and can be used for preparing materials such as one-dimensional perovskite quantum dots, two-dimensional perovskite quantum dots, nanowires, nano plates and the like; the defects of preparing the metal halide perovskite precursor solution by independently using DMF or GBL solvent in the preparation of the metal halide perovskite film are overcome; the perovskite precursor solution is prepared by using a DMF-GBL mixed solvent, the solvation intermediate formed by the perovskite raw material in the perovskite precursor solution preparation process has moderate solubility and proper solvent volatility, the solvation intermediate is quickly and uniformly crystallized in the high-speed spin coating process, and the annealing process is easy to control, so that the coverage rate, the flatness and the crystallinity of the perovskite film are improved, and the effects of improving the quality of the perovskite film and the performance of a device are achieved;

2) the method is simple to operate, good in repeatability and low in cost;

3) the prepared high-performance metal halide perovskite thin film can be used for devices such as solar cells, laser emitters, light emitting diodes, thermoelectric devices, photoelectric detectors and the like.

Drawings

FIG. 1a is an SEM image of a perovskite thin film prepared based on a solvent DMF;

FIG. 1b is an SEM image of a perovskite thin film prepared based on solvent GBL;

FIG. 1c is an SEM image of a perovskite thin film prepared based on the DMF/GBL mixed solvent in example 1;

FIG. 2 is a UV-VIS spectrum of a perovskite thin film prepared based on different proportions of DMF and GBL solvents;

FIG. 3 is a schematic diagram of a PIN structure of a perovskite solar cell.

Detailed Description

The invention is described in detail below with reference to the drawings and the detailed description.

Example 1

DMF and GBL are two organic solvents that vary considerably in nature. DMF has a relatively low boiling point of 153 ℃ and a polarity of 6.40D, and has strong ability to form hydrogen bonds and coordinate with metals. GBL has a relatively high boiling point of 204 c and a low polarity of 4.12D, and can form hydrogen bonds, but has a relatively weak coordination capacity with metals. The quality of the perovskite thin film directly depends on the type of solvent, the nature of the solvated intermediate, and the interaction between the solvent and the solvated intermediate, and both of the above solvents have disadvantages when they are used alone to prepare the perovskite thin film.

In this example, Scanning Electron Microscopy (SEM) and ultraviolet-visible light spectroscopy (UV-Vis) were performed on perovskite thin films prepared from perovskite precursor solutions with different solvent ratios. As shown in the scanning electron micrographs of fig. 1a, fig. 1b and fig. 1c, compared with the perovskite thin film prepared by using pure DMF and GBL as solvents, the perovskite thin film produced by using the DMF and GBL mixed solvent with the volume ratio of 6.5:3.5 has a significant improvement in crystal size and film morphology. In addition, according to the ultraviolet-visible light spectrum shown in fig. 2, the perovskite thin film produced by the mixed solvent of DMF and GBL with the volume ratio of 6.5:3.5 has good peak shape and strength, which indicates that the perovskite thin film with excellent morphology and larger crystal size can be obtained by the method, and the result is consistent with the conclusion obtained by a scanning electron microscope and the photoelectric performance of the battery.

Based on the mixed solvent in the invention, the solar cell with a planar inverted structure is assembled by adopting a solution one-step method, as shown in fig. 3, the solar cell comprises a conductive substrate 1, a hole transport layer 2, a perovskite thin film layer 3, an electron transport layer 4 and a top electrode 5 which are arranged in a stacked manner.

Comparing the effect of the perovskite thin film obtained by the mixed solvent with different compositions on the efficiency of the perovskite solar cell, wherein the statistics of photoelectric performance parameters of the cell are shown in table 1 (all data are obtained based on at least 8 independent cells), compared with pure DMF (average efficiency of 8.082%) or GBL (average efficiency of 8.601%) as a solvent, the perovskite thin film prepared by using the mixed solvent of DMF and GBL has obvious improvement on the cell performance, and when the volume ratio of DMF to GBL is 6.5:3.5, the cell performance is optimal, the average efficiency is 11.251%, and is improved by 39.21% compared with that of DMF alone; compared with the GBL solvent alone, the improvement is 30.81 percent. It can be seen that the mixed solvent significantly improves the battery performance through the improvement of the quality of the perovskite thin film. In addition, experiments also show that compared with a single solvent, the repeatability of the perovskite solar cell prepared by the mixed solvent is also obviously improved.

TABLE 1 parameters of the photoelectric Properties of perovskite solar cells

It is to be emphasized that: the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and all simple modifications, equivalent changes and modifications made to the above embodiments according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.

Claims

1. The solar cell is characterized BY comprising a conductive substrate, a hole transport layer, a perovskite thin film layer, an electron transport layer and a top electrode which are arranged in a stacked mode, wherein the perovskite thin film layer is obtained BY spin-coating a perovskite precursor solution on the hole transport layer in one step, and the perovskite precursor solution comprises at least one raw material AX and at least one raw material BY₂And a solvent; the solvent is a mixed solvent of DMF and GBL, and the volume ratio of DMF to GBL is 3: 2-3: 1;

the one-step spin coating perovskite precursor solution comprises the following steps:

S₁preparing a perovskite precursor solution:

at least one raw material AX and at least one raw material BY are mixed₂Adding the precursor solution into a solvent, and stirring at room temperature or under heating to prepare a precursor solution of the metal halide perovskite;

S₂preparing a perovskite thin film:

in a glove box or in the air, step S₁The prepared metal halide perovskite precursor solution is uniformly loaded on the hole transport layer, and is heated, annealed and cooled to room temperature after being crystallized to obtain a perovskite thin film;

the annealing temperature is 50-150 ℃, and the annealing time is 0.5-100 min.

2. The solar cell according to claim 1, wherein the volume ratio of DMF to GBL is 6.5: 3.5.

3. The solar cell according to claim 1, wherein the group A in the raw material AX is a monovalent, normal radical selected from the group consisting of NH₂-CH＝NH₂ ⁺、R₁NH₃ ⁺And a monovalent metal cation; x is a monovalent anion selected from the group consisting of I^-、Br^-、CI^-、SCN^-、NCS^-、NO^-、R₃COO^-Any one of them; r₁And R₂Respectively any one of alkane, alkene, alkyne or aromatic hydrocarbon group.

4. The solar cell as claimed in claim 1, wherein the raw material BY₂Wherein B is a positive divalent metal cation; y is a monovalent anion selected from the group consisting of I^-、Br^-、CI^-、SCN^-、NCS^-、NO^-、R₃COO^-Any one of them; r₃Is any one of alkane, alkene, alkyne or aromatic hydrocarbon group.