Oriented Quasi‐2D Perovskites for High Performance Optoelectronic Devices

作者：Rong Yang, Renzhi Li, Yu Cao, Yingqiang Wei, Yanfeng Miao, Wen Liang Tan, Xuechen Jiao, Hong Chen, Liangdong Zhang, Qing Chen, Huotian Zhang, Wei Zou, Yuming Wang, Ming Yang, Chang Yi, Nana Wang, Feng Gao, Christopher R. McNeill, Tianshi Qin, Jianpu Wang, Wei Huang · 发表于：Advanced Materials · 年份：2018 · DOI：10.1002/adma.201804771 · 被引用次数：361 · 研究领域：Perovskite Materials and Applications、2D Materials and Applications、Conducting polymers and applications

Abstract Quasi‐2D layered organometal halide perovskites have recently emerged as promising candidates for solar cells, because of their intrinsic stability compared to 3D analogs. However, relatively low power conversion efficiency (PCE) limits the application of 2D layered perovskites in photovoltaics, due to large energy band gap, high exciton binding energy, and poor interlayer charge transport. Here, efficient and water‐stable quasi‐2D perovskite solar cells with a peak PCE of 18.20% by using 3‐bromobenzylammonium iodide are demonstrated. The unencapsulated devices sustain over 82% of their initial efficiency after 2400 h under relative humidity of ≈40%, and show almost unchanged photovoltaic parameters after immersion into water for 60 s. The robust performance of perovskite solar cells results from the quasi‐2D perovskite films with hydrophobic nature and a high degree of electronic order and high crystallinity, which consists of both ordered large‐bandgap perovskites with the vertical growth in the bottom region and oriented small‐bandgap components in the top region. Moreover, due to the suppressed nonradiative recombination, the unencapsulated photovoltaic devices can work well as light‐emitting diodes (LEDs), exhibiting an external quantum efficiency of 3.85% and a long operational lifetime of ≈96 h at a high current density of 200 mA cm−2 in air.