时 间：2019年2月28日（星期四） 10:00 — 11:00

地 点：武汉光电国家研究中心A302

报告人：Dr. Gyumin Kim

邀请人：胡玥 副教授

Defect-less high performance organic-inorganic hybrid perovskite solar cells

Organic-inorganic hybrid perovskite solar cells (OIHPs) have attracted great attention recently due to their outstanding performances. With the advent of mixed cation/halide OIHPs,¹ the drawbacks such as hysteresis and instability in air have been somewhat solved. However, reproducibility and light-induced electronic instability of OIHPs still remain major problems inhibiting further steps toward commercialization. Here, we briefly introduce milestones to overcome those intrinsic problems mentioned above.

The poor reproducibility of OIHPs is more prone to happen for mixed cation/halide perovskites compared to single cation/halide perovskites. Examination of XRD reveals that any organicinorganic based perovskite precursor should be categorized into one of six different states. Only two states out of six have extreme sensitivity toward evaporation kinetics of DMSO during annealing, which are common for mixed cation/halide perovskites. This implies that the extra care should be taken into account for the fabrication of mixed cation/halide OIHPs.

Photo-induced optoelectronic instability is another issue regarding OIHPs. Generally, the constant voltage applied to OIHPs degrade the performances gradually. Here we introduced Ge-Pb as double cations to MA-FA-based perovskites. Different from the application of Ge into Cs-based perovskites,² major challenge for Ge into MAFA perovskite lies on the poor solubility in precursor solution. We

introduced chlorine-based organic additive to the precursor and improved solubility, resulting in smooth film of MAFA-based perovskites having Pb-Ge. Time-transient photoluminescence (TRPL) was greatly improved as well as the improvements of air stability. OHIP based on Ge-Pb displays stable output currents at constant voltage (V_max) while cells without Ge show degradation within 5 mins under the same measurement condition, suggesting that Ge can a promising candidate to stabilizing electronic output for OIHPs.

Reference

1. Jeon, N. J.; Noh, J. H.; Yang, W. S.; Kim, Y. C.; Ryu, S.; Seo, J.; Seok, S. I., Compositional engineering of perovskite materials for high-performance solar cells. Nature 2015, 517 (7535), 476.

2. Yang, F.; Hirotani, D.; Kapil, G.; Kamarudin, M. A.; Ng, C. H.; Zhang, Y. H.; Shen, Q.; Hayase, S., All-Inorganic CsPb1-xGexI2Br Perovskite with Enhanced Phase Stability and Photovoltaic Performance.

Angew Chem Int Edit 2018, 57 (39), 12745-12749.