Zhang Xiaobo, Ma Yang, Chen Xiaoqing, Li Xuhong, Zhou Wencai, Ouedraogo Nabonswende Aida Nadege, Shirai Yasuhiro, Zhang Yongzhe, Yan Hui
College of Material Sciences and Engineering, Beijing University of Technology Beijing 100124 China.
Key Laboratory of Optoelectronics Technology, Ministry of Education, Faculty of Information Technology, Beijing University of Technology Beijing 100124 China
RSC Adv. 2021 Oct 14;11(53):33637-33645. doi: 10.1039/d1ra05399j. eCollection 2021 Oct 8.
Flexible perovskite solar cells (PSCs) have attracted tremendous attention due to their potential application in portable and wearable electronics. However, the photoelectric conversion efficiency (PCE) of flexible PSCs is still far lower than that of usual rigid PSCs. Moreover, the mechanical stability of flexible PSCs cannot meet the needs of commercial applications because of the cracking of perovskite grains caused by bending stress. Here, we introduced a spacer cation additive (2-(chloromethyl) pyridine hydrochloride, CPHC) within the perovskite organic precursor to improve the device PCE and its mechanical stability. We observed that the CPHC spacer cation additive could simultaneously facilitate the crystallization of perovskite and stitch the grain boundaries to improve the flexibility. Compared to the 17.64% PCE of the control devices, the target flexible PSCs achieved a more highly efficiency over 19% with an improved mechanical stability (87.2% of the initial PCE after the 1000 cycles with the bending radius = 6 mm). In addition, compared to methylammonium or formamidinium cation, due to the stronger hydrophobic and larger activation energy barrier for the ion migration of the CPHC spacer cation, the device retained over 80% of the initial PCE after 30 days storage in an ambient environment.
柔性钙钛矿太阳能电池（PSCs）因其在便携式和可穿戴电子产品中的潜在应用而备受关注。然而，柔性PSCs的光电转换效率（PCE）仍远低于普通刚性PSCs。此外，由于弯曲应力导致钙钛矿晶粒开裂，柔性PSCs的机械稳定性无法满足商业应用的需求。在此，我们在钙钛矿有机前驱体中引入了一种间隔阳离子添加剂（2-（氯甲基）吡啶盐酸盐，CPHC），以提高器件的PCE及其机械稳定性。我们观察到，CPHC间隔阳离子添加剂可以同时促进钙钛矿的结晶并缝合晶界以提高柔韧性。与对照器件17.64%的PCE相比，目标柔性PSCs实现了超过19%的更高效率，且机械稳定性得到改善（在弯曲半径 = 6 mm的1000次循环后，初始PCE的87.2%）。此外，与甲铵或甲脒阳离子相比，由于CPHC间隔阳离子具有更强的疏水性和更大的离子迁移活化能垒，该器件在环境中储存30天后仍保留了超过80%的初始PCE。
