Imaging of Photoinduced Band Alignments and Carrier Generations at the PbI₂/perovskite Interface of Perovskite Solar Cells
Min-Chuan Shih1,2*, Shao-Sian Li3, Cheng-Hua Hsieh1, Ying-Chiao Wang3, Hung-Duen Yang1, Ya-Ping Chiu1,2,4,5, Chia-Seng Chang4, Chun-Wei Chen3,5
1Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan
2Department of Physics, National Taiwan University, Taipei, Taiwan
3Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan
4Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan
5Taiwan Consortium of Emergent Crystalline Materials (TCECM), Ministry of Science and Technology, Taiwan
* presenting author:Min-Chuan Shih,
The presence of PbI₂ in perovskite films has been found to affect the charge carrier transport behaviors and device performance of perovskite solar cells. In this work, we employed a novel light-modulated scanning tunneling microscopy (LM-STM) technique combined with spectroscopy (STS) to reveal the photoinduced carrier distributions and interfacial electronic structures at the PbI2/perovskite interface of polycrystalline CH₃NH₃PbI₃ perovskite grains under light illumination. Most importantly, this technique enabled us to directly observe the spatially-resolved mapping images of photogenerated electron and hole carriers and the photoinduced interfacial band bending of both the valence bands and conduction bands at the PbI₂/perovskite interface of perovskite crystals for the first time.

Keywords: X-STM, LM-STM, Perovskite