Melt-and air-processed selenium thin-film solar cells  

作　　者：Wenbo Lu Zongbao Li Mingjie Feng Hui-Juan Yan Bin Yan Liyan Hu Xing Zhang Shunchang Liu Jin-Song Hu Ding-Jiang Xue 

机构地区：[1]Beijing National Laboratory for Molecular Sciences(BNLMS),CAS Key Laboratory of Molecular Nanostructure and Nanotechnology,Institute of Chemistry,Chinese Academy of Sciences,Beijing100190,China [2]School of Material and Chemical Engineering,Tongren University,Tongren 554300,China [3]National Engineering Research Center for Advanced Polymer Processing Technology,Zhengzhou University,Zhengzhou 450002,China [4]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China Chemistry》2022年第11期2197-2204,共8页中国科学（化学英文版）

基　　金：supported by the National Science Foundation of China(21922512,21875264);Chinese Postdoctoral Science Foundation(2021MD703865);the Youth Innovation Promotion CAS(Y2021014);。

摘　　要：Elemental selenium(Se), as the world’s first but long-neglected photovoltaic material, has regained great interest recently in tandem solar cells as top cells due to its wide bandgap(~1.8 eV), simple, non-toxic and earth-abundant composition, and intrinsic environmental stability. In particular, Se possesses the lowest melting point of 217 °C among the photovoltaic absorbers reported so far, endowing Se with a unique advantage of film fabrication by blade coating the Se melt on substrate. However, the poor wettability of Se melt on widely-used photovoltaic functional layers such as TiO_(2) limits its melt processing. Here we introduce a wettability-modification strategy that decreases the contact angle of Se melt on substrate and improves the wettability by appropriately enhancing the heating temperature of molten Se while avoiding Se volatilization. We further reveal the mechanism of the inherent air stability of Se that originates from the high activation energy of oxygen chemisorption on Se(3.21 eV). This enables the realization of compact Se films through melt-based blade coating in ambient air. The resulting Se solar cells exhibit an efficiency of 3.5%. Unencapsulated devices show no efficiency loss after 1,000 h of storage under ambient conditions.

关 键 词：SELENIUM thin film PHOTOVOLTAIC melt processing 

分 类 号：TB383.2[一般工业技术—材料科学与工程] TM914.42[电气工程—电力电子与电力传动]