Yin, Jianghao; Zhao, Xiaoyang; Zhao, Ming; Zhang, Leng; Tian, Jiajia; Wei, Yaowei; Ma, Zhao; Zhou, Yi Source: Materials Today Communications, v 40, August 2024; E-ISSN: 23524928; DOI: 10.1016/j.mtcomm.2024.109725; Article number: 109725; Publisher: Elsevier Ltd

Author affiliation:

State Center for International Cooperation on Designer Low-Carbon & Environmental Materials (CDLCEM), School of Materials Science and Engineering, Zhengzhou University, Zhengzhou; 450001, China

Key Lab for Advanced Materials Processing Technology of Ministry of Education, School of Materials Science and Engineering, Tsinghua University, Beijing; 100084, China

School of Electronics and Information Engineering, Jinling Institute of Technology, Nanjing; 211169, China

Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing; 100083, China

Abstract:

The tandem solar cell is composed of a wide bandgap top subcell and a narrow bandgap bottom subcell, which is a promising technology to surpass the theoretical efficiency of single-junction solar cell. Since the currents are generated by photo-generated carriers and the two subcells are united in series, the absorber thickness should be adjusted with the change of the bandgaps to ensure that the two subcells have the same currents. In this study, the impacts of subcell bandgaps on perovskite/Cu(In,Ga)Se2 tandem solar cells were investigated using SCAPS-1D. For perovskite top subcells, the short-circuit current and power conversion efficiency increased with the absorber thickness increasing, and photons in short-wavelength part could be absorbed by perovskite solar cells, while photons in long-wavelength part were almost not absorbed. In tandem solar cells, the increasing bandgap of top subcell and the decreasing bandgap of bottom subcell required higher top subcell thickness to achieve the current matching condition. The top subcell bandgap needed to be wide enough and the bottom subcell bandgap needed to be narrow enough to get the same current. The efficiency increased as the top subcell bandgap increased to 1.7 eV, and started to decline with the further increase of bandgap. Moreover, the efficiency increased as the bottom subcell bandgap increased up to 1.28 eV, but decreased when the bandgap kept increasing. The optimized tandem solar cell achieved the highest efficiency of 32.71 % with the top subcell bandgap of 1.7 eV and the bottom subcell bandgap of 1.28 eV.