KR101294770B1

KR101294770B1 - Quantum dots photovoltaic

Info

Publication number: KR101294770B1
Application number: KR1020080117702A
Authority: KR
Inventors: 조은철
Original assignee: 현대중공업 주식회사
Priority date: 2008-11-25
Filing date: 2008-11-25
Publication date: 2013-08-08
Also published as: KR20100059063A

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quantum dot solar cell, and in particular, deposits a quantum dot layer in which a quantum dot (QD) is formed on a lower portion of a silicon wafer, and deposits a passivation layer in which a quantum dot is formed on the silicon wafer. It is characterized in that the surface recombination of the carriers generated in the silicon wafer is prevented by the quantum dots (QD) of the passivation layer.

According to the present invention, the energy level is quantized at the quantum dots of the passivation layer deposited on the silicon wafer, thereby preventing surface recombination of carriers generated by absorbing light in the silicon solar cell, thereby preventing solar cells. The effect of increasing the power generation efficiency can be expected.

Quantum dot, solar cell, silicon wafer, passivation layer, quantum dot layer, surface recombination,

Description

Quantum dot photovoltaic

The present invention relates to a quantum dot solar cell, and more particularly, to a quantum dot solar cell capable of increasing the power generation efficiency of a solar cell by preventing surface recombination of a carrier generated by absorbing light in a silicon solar cell.

Scientists developing solar cells are looking for materials and technical approaches that can convert sunlight into electricity with high efficiency.

Most commercially available solar cells have a theoretical efficiency limit of 31% in the form of single layer junctions with one PN junction.

Tandem solar cells are theoretically highly efficient and are being studied.

A typical example of a multilayer junction solar cell is designed to absorb different wavelengths of sunlight by stacking amorphous silicon and microcrystalline silicon, and is known to have an efficiency of about 10% in commercial modules.

Multi-junction solar cells using GaAs series have a conversion efficiency of more than 40% in the focused state.

FIG. 1 illustrates a conventional solar cell module, in which a P + layer 3 is deposited on a silicon wafer 1, a N + layer 2 is deposited on a silicon wafer 1, and the N + layer is deposited. A passivation layer (4), which is a protective film, is deposited on top of (2), and the passivation layer (4) is formed by depositing a silicon nitride (SiNx) by chemical vapor deposition. It is used as the passivation layer 4 which prevents the surface recombination of the carrier produced | generated in the silicon wafer 1.

However, the prior art has a problem in that the carrier surface recombination prevention efficiency of the passivation layer 4 formed by depositing a nitride film by chemical vapor deposition is low, and as a result, the power generation efficiency of the entire solar cell module is lowered.

Accordingly, the present invention for solving the above problems by depositing a passivation layer using a quantum dot on the silicon wafer to prevent the surface recombination of the carrier (Carrier) generated by absorbing light in the silicon solar cell power generation efficiency of the solar cell It is an object of the present invention to provide a quantum dot solar cell that can be increased.

The present invention for achieving the above object, by depositing a quantum dot layer on which the quantum dot (QD) is formed on the lower portion of the silicon wafer, by depositing a passivation layer on which the quantum dot is generated on the silicon wafer by silicon Surface recombination of the carriers produced in the wafer is characterized by being prevented by the quantum dots (QD) of the passivation layer.

According to the present invention, the energy level is quantized at the quantum dots of the passivation layer deposited on the silicon wafer, thereby preventing surface recombination of carriers generated by absorbing light in the silicon solar cell, thereby preventing the solar cell. The effect of increasing the power generation efficiency can be expected.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

The terms defined in describing the present invention have been defined in consideration of the functions of the present invention and should not be construed to limit the technical elements of the present invention.

FIG. 2 illustrates a basic configuration of a quantum dot solar cell of the present invention, in which a P + layer 12 is deposited on a lower portion of a silicon wafer 10 and a polarity different from that of a silicon wafer is formed on the upper surface of the silicon wafer 10. The passivation layer 11 having the quantum dots QDs formed thereon is deposited so that surface recombination of carriers generated in the silicon wafer 10 by sunlight is prevented by the quantum dots QDs of the passivation layer 11. .

The quantum dot QD of the passivation layer 11 is formed in an insulating film, such as an oxide film (SiO 2) or a nitride film (SiN x), or in a bandgap material higher than a quantum dot (eg, SiC, TiO 2, SnO 2, Al 2 O 3, etc.) silicon-Si, Germanium-Ge, Tin-Sn) quantum dots are applied.

When the passivation layer 11 in which the quantum dots QD are deposited is deposited on the silicon wafer 10, the band gap of the material may be freely controlled by the quantum confinement effect of the quantum dots.

The characteristics of the passivation layer 11 to which the quantum dot QD is applied are determined according to the size of the quantum dot, and the surface recombination rate change according to the size of the quantum dot is smaller as shown in FIG. Will slow down.

In addition, the passivation layer 11 has a mismatch in carrier concentration at the interface with silicon (that is, even when there are many recombinations of np at a carrier concentration n >> p or n << p, a large carrier concentration is maintained large). Compared to the conventional SiN thin film, the Al2O3 thin film can be used as a more effective passivation layer by generating a difference in carrier concentration at the silicon interface due to negative charge in the foil.

In the quantum dot solar cell module of the present invention as shown in FIG. 2, since the carrier generated in the silicon wafer 10 by sunlight is prevented from recombining the surface by the quantum dot QD forming the passivation layer 11, the lower P + layer Flowing to (12) has the effect of improving the power generation efficiency.

Meanwhile, FIG. 3 illustrates another embodiment of the present invention, in which a quantum dot layer 13 in which a quantum dot QD is formed is deposited on a lower portion of a silicon wafer 10, and an upper portion of the silicon wafer 10 is formed. The passivation layer 11 having the quantum dots QD formed thereon is deposited so that surface recombination of carriers generated in the silicon wafer 10 by sunlight is prevented by the quantum dots QD of the passivation layer 11. .

In this case, when the silicon wafer 10 is a P-type silicon substrate, the passivation layer 11 is formed of an N + quantum dot layer (N + QD), and the lower quantum dot layer 13 is formed of a P + quantum dot layer. 3 (b) see)

In addition, when the silicon wafer 10 is an N-type silicon substrate, the passivation layer 11 is formed of a P + quantum dot layer (P + QD), and the lower quantum dot layer 13 is an N + quantum dot as shown in FIG. Form into layers.

The silicon quantum dots can adjust the bandgap of the material according to the size of the quantum dots as shown in FIG. 5, and the bandgap of the silicon is 1.1 eV, forming heterojunctions with the silicon quantum dots having a size of 2 nm. Thus, the basic structure of the solar cell is achieved.

1 is a view showing a conventional solar cell module.

2 is a view showing a basic configuration of a quantum dot solar cell module of the present invention.

3 is a view showing another embodiment of a quantum dot solar cell module of the present invention.

Figure 4 is a graph showing the surface recombination rate change according to the size of the quantum dot in the present invention.

5 is a view showing a band gap according to the size of the quantum dot in the present invention.

Description of the Related Art [0002]

10: silicon wafer, 11: passivation layer and charge separation layer,

12: P + layer, 13: quantum dot layer,

Claims

Deposit a P + layer on the bottom of the silicon wafer,

Depositing a passivation layer in which a quantum dot is formed on the silicon wafer,

The size of the quantum dots is 2 nm, and

The quantum dot of the passivation layer is a quantum dot solar cell, characterized in that configured to prevent surface recombination of carriers generated in the silicon wafer by sunlight.

Depositing and forming a quantum dot layer having quantum dots formed under the silicon wafer,

The size of the quantum dots is 2 nm, and

3. The method according to claim 1 or 2,

The quantum dot of the passivation layer is formed of an insulating film such as an oxide film (SiO 2) or a nitride film (SiN x) or a material of any one of SiC, TiO 2 and SnO 2.

3. The method according to claim 1 or 2,

If the silicon wafer is a P-type silicon substrate passivation layer is a quantum dot solar cell, characterized in that the N + quantum dot layer.

3. The method according to claim 1 or 2,

If the silicon wafer is an N-type silicon substrate, the passivation layer is a quantum dot solar cell, characterized in that the P + quantum dot layer.