Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7935408 | Solar Energy | 2018 | 7 Pages |
Abstract
The short-wavelength response for traditional CdS/CdTe thin film solar cells was dramatically restricted by the CdS window layer. In order to increase short-wavelength light collection, we tried to replace CdS with MgxZn1âxO (MZO). The short-wavelength quantum efficiency (QE) response was obviously increased to more than 80% at 400â¯nm, while fill factor (FF) and open circuit voltage (Voc) for CdTe solar cells were decreased. This decrease was mainly caused by the weak build-in potential formed by the MZO/CdTe heterojunction, which resulted in insufficient driving force to repel the photo-generated carriers. Hence, the thin CdS buffer layer was introduced between MZO and CdTe to improve the built-in potential. It efficiently increased the build-in potential from 0.369 to 0.579â¯V with an obvious improvement of FF and Voc. But this interlayer caused QE losses to some degree in the short-wavelength region. To avoid these losses, a composite CdS/CdSe buffer layer was incorporated in the CdTe solar cells. CdSe acted as a protective layer to avoid the excessive CdS consumption during the high temperature deposition processing of the CdTe absorption layer. Meanwhile the formation of CdSexTe1âx by inter-diffusion extended the long-wavelength response. Thus, cell performance was enhanced with a relatively high build-in potential 0.517â¯V and a substantial improvement of the QE response.
Keywords
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Physical Sciences and Engineering
Energy
Renewable Energy, Sustainability and the Environment
Authors
Taowen Wang, Shengqiang Ren, Chunxiu Li, Wei Li, Cai Liu, Jingquan Zhang, Lili Wu, Bing Li, Guanggen Zeng,