Approaching the Fill Factor Limit in Dopant-Free Hole Transporting Layer-Based All-Inorganic Perovskite Solar Cells

Kanghui Zheng; Chang Liu; Kuibao Yu; Yuanyuan Meng; Xu Yin; Shixiao Bu; Shuyuan Lin; Cuirong Liu; Ziyi Ge

doi:10.1021/acsami.2c19954

Approaching the Fill Factor Limit in Dopant-Free Hole Transporting Layer-Based All-Inorganic Perovskite Solar Cells

ACS Appl Mater Interfaces. 2023 Mar 10. doi: 10.1021/acsami.2c19954. Online ahead of print.

Authors

Kanghui Zheng^{1

2}, Chang Liu¹, Kuibao Yu¹, Yuanyuan Meng¹, Xu Yin², Shixiao Bu¹, Shuyuan Lin¹, Cuirong Liu², Ziyi Ge¹

Affiliations

¹ Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo 315201, P. R. China.
² College of Materials Technology and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, P. R. China.

PMID: 36897231
DOI: 10.1021/acsami.2c19954

Abstract

As an important part of perovskite solar cells (PSCs), hole transporting layer (HTL) has a critical impact on the performance and stability of the devices. In an attempt to alleviate the moisture and thermal stability issues from the commonly used HTL Spiro-OMeTAD with dopant, it is urgent to develop novel HTLs with high stability. In this study, a new class of polymers D18 and D18-Cl are applied as undoped HTL for CsPbI₂Br-based PSCs. In addition to the excellent hole transporting properties, we unveil that D18 and D18-Cl with larger thermal expansion coefficient than that of CsPbI₂Br could impose a compressive stress onto the CsPbI₂Br film upon thermal treatment, which could release the residual tensile stress in the film. As a result, the efficiency of CsPbI₂Br-based PSCs with D18-Cl as HTL reaches 16.73%, and the fill factor (FF) exceeds 85%, which is one of the highest FF records for the conventional-structured device to date. The devices also show impressive thermal stability with over 80% of the initial PCE retained after 85 °C heating for 1500 h.

Keywords: CsPbI2Br; D18-Cl; dopant-free HTL; high FF; residual tensile stress.