Kim Sohyeon, Jang Jun Hyeok, Wu Ziang, Lee Mi Jung, Woo Han Young, Hwang Inchan
Department of Electronic Materials Engineering, Kwangwoon University, Seoul, 01897, Republic of Korea.
School of Advanced Materials Engineering, Kookmin University, Seoul, 02707, Republic of Korea.
Small. 2021 Aug;17(33):e2101839. doi: 10.1002/smll.202101839. Epub 2021 Jul 6.
The ideality factor (n ) and photoluminescence (PL) analyses assess charge recombination characteristics in perovskite solar cells (PeSCs). However, their correlations with open-circuit voltage (V ) are often found to be complicated depending on the recombination types in the devices. Herein, the correlation of n , PL characteristics and V is elucidated depending on the interfacial crystal quality in triple-cation mixed-halide perovskite, Cs (MA FA ) Pb(I Br ) , deposited on different hole transport layers (HTLs). In the devices with low quality interfacial crystals, V increases together with n , which originates from the light intensity-dependence of majority carrier at the interface. Meanwhile, a negative correlation between V and n is observed for devices with high quality interfacial crystals. The authors discuss the cases that PL enhancement by the improvement of overall crystal quality can fail to correlate with a V increase if interfacial crystal quality becomes worse. The study highlights that interfacial crystal quality evaluation can help to understand charge recombination via n and PL measurements, and more importantly provide information of which defect engineering between at the interface and in the bulk would be more effective for device optimization.
理想因子（n）和光致发光（PL）分析用于评估钙钛矿太阳能电池（PeSCs）中的电荷复合特性。然而，根据器件中的复合类型，它们与开路电压（V）的相关性往往很复杂。在此，根据沉积在不同空穴传输层（HTLs）上的三阳离子混合卤化物钙钛矿Cs（MA FA）Pb（I Br）中的界面晶体质量，阐明了n、PL特性与V之间的相关性。在界面晶体质量较差的器件中，V随n的增加而增加，这源于界面处多数载流子对光强的依赖性。同时，对于界面晶体质量较高的器件，观察到V与n之间存在负相关。作者讨论了如果界面晶体质量变差，通过提高整体晶体质量实现的PL增强可能与V的增加不相关的情况。该研究强调，界面晶体质量评估有助于通过n和PL测量来理解电荷复合，更重要的是提供信息，表明界面处和体相中哪种缺陷工程对器件优化更有效。
