Li Rui, Zhang Huanyu, Han Xing, Huo Xiangtao, Zhang Mei, Guo Min
School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, PR China.
ACS Appl Mater Interfaces. 2020 Mar 4;12(9):10515-10526. doi: 10.1021/acsami.9b22556. Epub 2020 Feb 21.
Organic-inorganic hybrid perovskite solar cells (PSCs) have become a research hotspot because of their excellent power conversion efficiency (PCE), but the presence of toxic lead (Pb) in perovskite films has significantly limited their commercial applications. In this study, using a TiO nanorod array (TNRA) as the electron transport layer, strontium chloride (SrCl) was chosen to fabricate lead-less PSCs in air (relative humidity, RH = 50%) by a simple two-step spin-coating method. The influence of introduced strontium (Sr) on the perovskite films and cell properties was systematically investigated by various characterization methods. With an increasing Sr substitution amount from 0 to 15 mol %, the formed perovskite films with a compact structure and large crystalline size essentially remained invariable, while the amount of residual PbI was reduced, which is beneficial for the cell performance. An optimal PCE of 16.08% (average PCE = 15.37%) was obtained for the 5 mol % Sr-substituted PSCs because of the enhanced charge extraction from the perovskite films to the TNRAs and the suppressed charge recombination in the PSCs. Both the humidity and thermal stability of the Sr-substituted PSCs were improved. More importantly, the 15 mol % Sr-substituted PSCs still exhibited a PCE of 15.09% in air (RH = 50%), maintaining 99% of the cell efficiency of the pristine (0 mol % Sr) PSC (15.27%), suggesting that the structure of TNRAs is suitable for the synthesis of high-performance Sr-substituted lead-less PSCs.
有机-无机杂化钙钛矿太阳能电池（PSCs）因其优异的功率转换效率（PCE）而成为研究热点，但钙钛矿薄膜中有毒铅（Pb）的存在显著限制了其商业应用。在本研究中，以TiO纳米棒阵列（TNRA）作为电子传输层，通过简单的两步旋涂法，选择氯化锶（SrCl）在空气中（相对湿度，RH = 50%）制备无铅PSCs。通过各种表征方法系统研究了引入的锶（Sr）对钙钛矿薄膜和电池性能的影响。随着Sr取代量从0增加到15 mol%，形成的具有致密结构和大晶体尺寸的钙钛矿薄膜基本保持不变，而残余PbI的量减少，这有利于电池性能。对于5 mol% Sr取代的PSCs，由于从钙钛矿薄膜到TNRAs的电荷提取增强以及PSCs中电荷复合的抑制，获得了16.08%的最佳PCE（平均PCE = 15.37%）。Sr取代的PSCs的湿度和热稳定性均得到改善。更重要的是，15 mol% Sr取代的PSCs在空气中（RH = 50%）仍表现出15.09%的PCE，保持了原始（0 mol% Sr）PSC（15.27%）电池效率的99%，表明TNRAs结构适用于合成高性能Sr取代的无铅PSCs。
