Gu Jinyu, Yan Gangbin, Lian Yuebin, Mu Qiaoqiao, Jin Huidong, Zhang Zaichao, Deng Zhao, Peng Yang
Soochow Institute for Energy and Materials Innovations, College of Physics, Optoelectronics and Energy, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University Suzhou 215006 P. R. China
Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University Suzhou 215006 P. R. China.
RSC Adv. 2018 Jul 18;8(45):25802-25807. doi: 10.1039/c8ra04422h. eCollection 2018 Jul 16.
Inorganic defect halide compounds such as CsBiI have been regarded as promising alternatives to overcome the instability and toxicity issues of conventional perovskite solar cells. However, their wide indirect bandgaps and deep defect states severely limit their photoelectronic conversion efficiency when implemented in devices. Trivalent cation substitution has been proposed by previous calculations allowing the engineering of their band structures, but experimental evidences are still lacking. Herein we use the trivalent cation Ru to partially replace Bi in CsBiI, and reveal their structural and optoelectronic properties, as well as the environmental stability. The Ru-doped CsBiI shows a decreasing bandgap with the increasing doping levels and an overall up-shift of band structure, owing to the dopant-induced defect states and thus enhanced phonon-electron coupling. As a result, upon Ru doping, the narrowed bandgap and the upward shift of the band structures might facilitate and broaden their applications in optoelectronic devices.
无机缺陷卤化物化合物，如CsBiI，被认为是克服传统钙钛矿太阳能电池不稳定性和毒性问题的有前途的替代品。然而，当应用于器件时，它们宽的间接带隙和深的缺陷态严重限制了它们的光电转换效率。先前的计算提出了三价阳离子取代，允许对其能带结构进行工程设计，但仍缺乏实验证据。在此，我们使用三价阳离子Ru部分取代CsBiI中的Bi，并揭示其结构和光电性质以及环境稳定性。Ru掺杂的CsBiI随着掺杂水平的增加带隙减小，能带结构整体上移，这是由于掺杂剂诱导的缺陷态以及由此增强的声子-电子耦合。结果，Ru掺杂后，变窄的带隙和能带结构的上移可能促进并拓宽它们在光电器件中的应用。
