Heo Jin Hyuck, Kim Jongseob, Kim Hyungjun, Moon Sang Hwa, Im Sang Hyuk, Hong Ki-Ha
Department of Chemical and Biological Engineering , Korea University , 145 Anam-ro , Seongbuk-gu, Seoul 02841 , Korea.
Samsung Electronics Co., Ltd , 130 Samsung-ro , Yeongtong-gu, Suwon-si , Gyeonggi-do 16678 , Korea.
J Phys Chem Lett. 2018 Oct 18;9(20):6024-6031. doi: 10.1021/acs.jpclett.8b02555. Epub 2018 Oct 4.
Preserving the stability of Sn-based halide perovskites is a primary concern in developing photovoltaic light-absorbing materials for lead-free perovskite solar cells. Whereas the addition of SnX (X = F, Cl, Br) has been demonstrated to improve the photovoltaic performance of Sn halide perovskite solar cells, the mechanistic roles of SnX in the performance enhancement have not yet been studied appropriately. Here we perform a comparative study of CsSnI films and devices and examine how SnX additives affect their stability, and the results are corroborated by first-principles-based theoretical calculations. Unlike the conventional belief that the additives annihilate defects, we find that the additives effectively passivate the surface and stabilize the perovskite phase, promoting the stability of CsSnI. Our mechanism suggests that SnBr, which shows ca. 100 h of prolonged stability along with a high power conversion efficiency of 4.3%, is the best additive for enhancing the stability of CsSnI.
在开发用于无铅钙钛矿太阳能电池的光伏吸光材料时，保持锡基卤化物钙钛矿的稳定性是首要关注的问题。虽然已证明添加SnX（X = F、Cl、Br）可改善锡卤化物钙钛矿太阳能电池的光伏性能，但SnX在性能增强中的作用机制尚未得到恰当研究。在此，我们对CsSnI薄膜和器件进行了比较研究，并考察了SnX添加剂如何影响其稳定性，基于第一性原理的理论计算证实了这些结果。与传统观点认为添加剂可消除缺陷不同，我们发现添加剂能有效钝化表面并稳定钙钛矿相，从而提高CsSnI的稳定性。我们的机制表明，SnBr是增强CsSnI稳定性的最佳添加剂，它能使稳定性延长约100小时，同时具有4.3%的高功率转换效率。
