He Jian, Ng Chun-Fai, Young Wong King, Liu Weifeng, Chen Tao
Department of Materials Science and Engineering, Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, P. R. China.
Department of Physics, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, P. R. China.
Chempluschem. 2016 Dec;81(12):1292-1298. doi: 10.1002/cplu.201600415. Epub 2016 Sep 29.
Organic-inorganic hybrid perovskite solar cells have achieved high power conversion efficiencies (PCE) of around 22 %, comparable to conventional silicon and thin-film solar cells. However, the poor stability of the perovskite material is one of the significant drawbacks for its practical application. In moderate humidity, the perovskite hydrates and decomposes within hours or a few days, which deteriorates the device efficiency rapidly. Herein, is demonstrated the moisture stability and photostability of CH NH PbI can be greatly improved through the interaction between ethyl cellulose (EC) and perovskite crystals. It is found that the CH NH PbI film with EC incorporation is stable over 5 days in 60 % relative humidity (RH) under ambient indoor light, whereas the conventional CH NH PbI film without EC is degraded in 1 day. After being stored in 60 % RH under ambient indoor light for 2.5 days, the solar cell with EC incorporation shows a PCE decrement from 14.08 % to 8.21 %, whereas that without EC is nearly entirely degraded (PCE=0 %). Nuclear magnetic resonance (NMR) spectroscopy shows that hydrogen bonding between EC and CH NH PbI accounts for the improved moisture stability by stabilizing the crystal structure.
有机-无机杂化钙钛矿太阳能电池已实现了约22%的高功率转换效率（PCE），与传统的硅基和薄膜太阳能电池相当。然而，钙钛矿材料稳定性差是其实际应用的一个重大缺陷。在适度湿度下，钙钛矿会在数小时或数天内发生水合和分解，这会迅速降低器件效率。在此，通过乙基纤维素（EC）与钙钛矿晶体之间的相互作用，证明了CH₃NH₃PbI₃的湿度稳定性和光稳定性可得到极大提高。研究发现，掺入EC的CH₃NH₃PbI₃薄膜在室内环境光下、相对湿度（RH）为60%的条件下5天内保持稳定，而未掺入EC的传统CH₃NH₃PbI₃薄膜在1天内就会降解。在室内环境光下、60%RH条件下储存2.
