A Study of Interfacial Electronic Structure at the CuPc/CsPbI2Br Interface

Crystals

Guoping Xiao¹  Chenyue Wang¹  Zhen Wang¹  Xingyu Gao¹  Liujiang Zhang¹  Li Chen¹  Zengguang Tang¹  Zhenhuang Su¹ 

[1] Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China;

关键词: all-inorganic perovskite solar cell;    energy level alignment;    interfacial electronic structure;   

DOI  :  10.3390/cryst11050547

来源: DOAJ

【 摘 要 】

In this article, CsPbI₂Br perovskite thin films were spin-coated on FTO, on which CuPc was deposited by thermal evaporation. The electronic structure at the CsPbI₂Br/CuPc interface was examined during the CuPc deposition by in situ X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) measurements. No downward band bending was resolved at the CsPbI₂Br side, whereas there is ~0.23 eV upward band bending as well as a dipole of ~0.08 eV identified at the molecular side. Although the hole injection barrier as indicated by the energy gap from CsPbI₂Br valance band maximum (VBM) to CuPc highest occupied molecular orbital (HOMO) was estimated to be ~0.26 eV, favoring hole extraction from CsPbI₂Br to CuPc, the electron blocking barrier of ~0.04 eV as indicated by the offset between CsPbI₂Br conduction band minimum (CBM) and CuPc lowest unoccupied molecular orbital (LUMO) is too small to efficiently block electron transfer. Therefore, the present experimental study implies that CuPc may not be a promising hole transport material for high-performance solar cells using CsPbI₂Br as active layer.

【 授权许可】

Unknown