The rapid relaxation of hot carriers results in energy loss in the form of heat, thus limiting the theoretical efficiency limit of single-junction solar cells. However, this issue has not received much attention in tin-lead perovskite solar cells .
Zhou Zhongmin and Feifei Xin of Qingdao University of Science and Technology, Chongwen Li of the University of Toronto and others introduced tin (II) oxalate (SnC2O4) into the tin-lead perovskite precursor solution to adjust the hot carrier cooling kinetics. The addition of SnC2O4 increases the length of carrier diffusion, prolongs the lifetime of carriers, and slows down the cooling rate of carriers. In addition, SnC2O4 can combine with uncoordinated Sn2+ and Pb2+ ions to regulate the crystallization of perovskite and achieve large grains.
The strong reducing property of C2O42- can inhibit the oxidation of Sn2+ to Sn4+ and minimize the formation of tin vacancies in the perovskite film. In addition, as a substitute for tin(II) fluoride, the introduction of SnC2O4 avoids the carrier transport problem caused by the accumulation of F- ions at the interface. As a result, the SnC2O4-treated tin-lead battery showed a championship efficiency of 23.36%, and the efficiency of the all-perovskite tandem solar cell was 27.56%. Furthermore, SnC2O4-treated devices showed excellent long-term stability. This discovery is expected to pave the way for stable and efficient all-perovskite tandem solar cells.
W. Yan, C. Li, C. Peng, S. Tan, J. Zhang, H. Jiang, F. Xin, F. Yue, Z. Zhou, Hot-carrier Cooling Regulation for Mixed Sn-Pb Perovskite Solar Cells. Adv. Mater. 2024, 2312170.
DOI: 10.1002/adma.202312170
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