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Back contact layer structure and CdTe solar battery comprising back contact layer structure

A solar cell, back contact technology, applied in circuits, photovoltaic power generation, electrical components, etc., can solve problems such as large diffusion coefficient and battery performance degradation

Inactive Publication Date: 2015-02-18
UNIV OF SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the large diffusion coefficient of Cu in CdTe in the back contact structure at room temperature, under long-term working conditions, Cu will diffuse into CdTe and CdS / CdTe junctions along the grain boundaries, resulting in attenuation of battery performance.

Method used

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  • Back contact layer structure and CdTe solar battery comprising back contact layer structure
  • Back contact layer structure and CdTe solar battery comprising back contact layer structure
  • Back contact layer structure and CdTe solar battery comprising back contact layer structure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0041] (1) Chemical etching of CdTe surface

[0042] Put the surface-cleaned glass / transparent conductive film / cadmium sulfide / cadmium telluride thin film structure sample into phosphoric acid nitric acid solution (volume ratio: nitric acid: phosphoric acid: water = 1:70:29) and etch for 5 to 50 seconds, etch After finishing, the sample surface was rinsed with deionized water, and then blown dry with N2.

[0043] (2) Deposition of Cu metal film

[0044] Put the etched sample into the vacuum chamber with a vacuum degree of 5×10 -6 Pa, using the electron beam evaporation method, deposited a 2nm thick Cu metal layer on the surface of the sample.

[0045] (3) Deposition V 2 o 5 film

[0046] The deposited Cu film samples were placed in the vacuum chamber of the magnetron sputtering instrument, and V 2 o 5 film. In the background vacuum (5×10 -3 Pa) under the condition, feed oxygen and argon into the system at the same time. The magnetron sputtering atmosphere is a mixed ...

Embodiment approach 2

[0048] (1) Chemical etching of CdTe surface

[0049] Put the glass / transparent conductive film / cadmium sulfide / cadmium telluride film structure sample with clean surface into bromine methanol solution (the volume ratio of bromine to methanol is 1:1000) and etch for 5 to 50 seconds, and use The surface of the sample was rinsed with deionized water and then washed with N 2 blow dry.

[0050] (2) Deposition of Cu metal film

[0051] Put the etched sample into the vacuum chamber with a vacuum degree of 5×10 -6 Pa, using the electron beam evaporation method to deposit a 1nm thick Cu metal layer on the surface of the sample.

[0052] (3) Deposition of MoO 3 film

[0053] Put the deposited Cu film sample into the vacuum chamber of the magnetron sputtering instrument, and use 4N pure MoO 3 Preparation of MoO by radio frequency sputtering on the target 3 film. In the background vacuum (5×10 -3 Pa) under the condition, feed oxygen and argon into the system at the same time. Th...

Embodiment approach 3

[0055] (1) Dry etching of CdTe surface

[0056] Place the glass / transparent conductive film / cadmium sulfide / cadmium telluride film structure sample with clean surface in vacuum (5×10 -3 Pa) conditions, using plasma beam (argon ion) bombardment method to remove excess CdCl on the surface 2 and oxides produced during heat treatment. The process is carried out in a pure argon atmosphere of 0.2-0.4Pa, and the bombardment power and beam current are related to the size of the sample area. The bombardment time is about 10 minutes.

[0057] (2) Deposition of Cu metal film

[0058] Put the etched glass / TCO / CdS / CdTe into a vacuum chamber with a vacuum degree of 5×10 -6 Pa, using the electron beam evaporation method, deposited a 1nm thick Cu metal layer on the surface of the sample.

[0059] (3) Deposition V 2 o 5 film

[0060] The sample of deposited Cu thin film was put into the vacuum chamber of thermal evaporation, and the purity of 99.95% V 2 o 5 The powder is used as the ...

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Abstract

The invention discloses a back contact layer structure and a CdTe solar battery comprising the back contact layer structure. The quantity of Cu elements required by implementation of ohm back contact is greatly decreased by introducing a high-work function transitional metal oxide layer between a CdTe thin film and a metal back electrode; meanwhile, the transitional metal oxide layer achieves an effect of preventing metal atoms in the metal back electrode from being dispersed to a CdTe and CdS / CdTe p-n node; therefore, the stability of the back contact electrode is improved, and high-conversion efficiency of the battery and the long-term stability of the battery in a use process are guaranteed.

Description

technical field [0001] The disclosure belongs to the field of preparation of solar photovoltaic devices, in particular to a back contact layer structure and a CdTe solar cell comprising the same. Background technique [0002] CdTe is a II-VI direct bandgap semiconductor with a bandgap width of 1.45eV, and has the best energy band structure and bandgap suitable for solar photoelectric conversion. The absorption coefficient of CdTe film is as high as 10 5 cm -1 , only need 2 micron thickness, it can absorb 99% of photons whose energy is higher than its forbidden band width in the incident sunlight. Therefore, CdTe has been widely concerned as a promising material for thin-film solar cells. CdTe thin film solar cells generally adopt the following heterojunction multilayer device structure: high light transmittance glass / transparent conductive oxide / N-type cadmium sulfide / P-type cadmium telluride / back electrode. Its theoretical conversion efficiency is 29%, and the highest c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L31/0224H01L31/18
CPCH01L31/022441H01L31/18Y02E10/50Y02P70/50
Inventor 王德亮沈凯王德钊杨瑞龙
Owner UNIV OF SCI & TECH OF CHINA
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