Boosting electron transport and reducing open-circuit voltage deficit of CIGS solar cells with Zn1−xMgxO buffer layer.

Autor: Liu, Yunfeng, Yao, Yifeng, Du, Qian, Yang, Chunlei, Li, Weimin, Liu, YiMing, Zhao, Chenchen, Sun, Yun, Liu, Wei
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Zdroj: Journal of Materials Science: Materials in Electronics; Dec2022, Vol. 33 Issue 35, p26434-26446, 13p
Abstrakt: Cd-free Cu(In,Ga)Se2 (CIGS) solar cells are more promising by comparing with the Cd-containing solar cells due to its merit of environmentally friendly nature. In order to further improve the short-circuit current, wide bandgap Zn(O,S) has recently been used as buffer layer instead of CdS. However, substituting CdS and ZnO films with single-layer Zn(O,S) can usually cause current leakage and aggravate carrier recombination. Herein, Zn1−xMgxO (ZMO) films were prepared between the Zn(O,S) and Al-doped ZnO as the second buffer layer. It is found that the bandgap and crystallinity of the ZMO film can be regulated by controlling the sputtering power. The morphology of the ZMO films revealed that the vertical columnar grain structure favorable for electron transport can be prepared at higher sputtering power, enhancing the short-circuit current density. Furthermore, the quality factor reduction and activation energy of recombination close to CIGS thin-film bandgap indicate that the interface recombination and open-circuit voltage deficit are reduced. Finally, a peak efficiency of 16.58% in Cd-free CIGS solar cells was achieved with high open-circuit voltage (Voc) (664 mV) and fill factor (74.5%). Voc of Cd-free CIGS solar cells has reached the same value as that of CdS/CIGS devices. These results demonstrate that deposited ZMO as the second buffer layer plays an important role in the reduction of Voc deficit in CIGS solar cells. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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