Lin Zhenhua, Zhu Hai, Zhou Long, Du Jianhui, Zhang Chunfu, Xu Qing-Hua, Chang Jingjing, Ouyang Jianyong, Hao Yue
State Key Laboratory of Wide Band Gap Semiconductor Technology, Shaanxi Joint Key Laboratory of Graphene, School of Microelectronics, Xidian University 2 South Taibai Road Xi'an China 710071
Department of Chemistry, National University of Singapore 3 Science Drive 3 Singapore 117543.
RSC Adv. 2018 Mar 22;8(21):11455-11461. doi: 10.1039/c8ra01199k. eCollection 2018 Mar 21.
The performance of perovskite solar cells (PSCs) including device efficiency and stability is mainly dependent on the perovskite film properties which are critically related to the organic cations used. Herein, we studied the role that the inorganic lithium (Li) cation played in perovskite thin films and its influence on crystal growth, film properties, and device performance. We found that within the threshold limit of a 1.0% molar ratio, the Li dopant had a positive effect on the film formation and properties. However, after replacing more MA with Li, the device performance was degraded significantly with reduced short-circuit current density ( ) and fill factor (FF) values. With a doping ratio of 10 mol%, the film morphology, crystallinity, photophysical, and electronic properties totally changed due to the unstable nature of the Li doped, distorted 3-D perovskite structure. The Li doping mechanism was discussed, and it was thought to contain two different doping mechanisms. One is interstitial doping at the much lower doping ratio, and the other is substitutional doping for the MA cation at the higher doping ratio.
包括器件效率和稳定性在内的钙钛矿太阳能电池（PSC）的性能主要取决于与所使用的有机阳离子密切相关的钙钛矿薄膜特性。在此，我们研究了无机锂（Li）阳离子在钙钛矿薄膜中所起的作用及其对晶体生长、薄膜特性和器件性能的影响。我们发现，在1.0%摩尔比的阈值范围内，Li掺杂剂对薄膜形成和特性有积极影响。然而，在用Li取代更多的甲脒（MA）后，器件性能显著下降，短路电流密度（ ）和填充因子（FF）值降低。在10 mol%的掺杂比例下，由于Li掺杂的、扭曲的三维钙钛矿结构的不稳定性质，薄膜形态、结晶度、光物理和电子特性完全改变。讨论了Li掺杂机制，认为其包含两种不同的掺杂机制。一种是在低得多的掺杂比例下的间隙掺杂，另一种是在较高掺杂比例下对MA阳离子的替代掺杂。
