Tan Shaun, Yavuz Ilhan, De Marco Nicholas, Huang Tianyi, Lee Sung-Joon, Choi Christopher S, Wang Minhuan, Nuryyeva Selbi, Wang Rui, Zhao Yepin, Wang Hao-Cheng, Han Tae-Hee, Dunn Bruce, Huang Yu, Lee Jin-Wook, Yang Yang
Department of Materials Science and Engineering and California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA.
Department of Physics, Marmara University, 34722, Ziverbey, Istanbul, Turkey.
Adv Mater. 2020 Mar;32(11):e1906995. doi: 10.1002/adma.201906995. Epub 2020 Feb 4.
The operational instability of perovskite solar cells (PSCs) is known to mainly originate from the migration of ionic species (or charged defects) under a potential gradient. Compositional engineering of the "A" site cation of the ABX perovskite structure has been shown to be an effective route to improve the stability of PSCs. Here, the effect of size-mismatch-induced lattice distortions on the ion migration energetics and operational stability of PSCs is investigated. It is observed that the size mismatch of the mixed "A" site composition films and devices leads to a steric effect to impede the migration pathways of ions to increase the activation energy of ion migration, which is demonstrated through multiple theoretical and experimental evidence. Consequently, the mixed composition devices exhibit significantly improved thermal stability under continuous heating at 85 °C and operational stability under continuous 1 sun illumination, with an extrapolated lifetime of 2011 h, compared to the 222 h of the reference device.
众所周知，钙钛矿太阳能电池（PSC）的运行不稳定性主要源于离子物种（或带电缺陷）在电位梯度下的迁移。ABX钙钛矿结构“A”位阳离子的成分工程已被证明是提高PSC稳定性的有效途径。在此，研究了尺寸失配引起的晶格畸变对PSC离子迁移能量学和运行稳定性的影响。观察到混合“A”位组成薄膜和器件的尺寸失配会导致空间效应，阻碍离子迁移路径，从而增加离子迁移的活化能，这通过多种理论和实验证据得到了证明。因此，与参考器件的222小时相比，混合组成器件在85°C连续加热下表现出显著提高的热稳定性，在连续1个太阳光照下表现出运行稳定性，外推寿命为2011小时。
