Enhancing perovskite solar cells efficiency through cesium fluoride mediated surface lead iodide modulation

Junming Chen; Kun Xu; Weicheng Xie; Lishuang Zheng; Yulu Tian; Jue Zhang; Jiahui Chen; Tianyuan Liu; Hanzhong Xu; Kun Cheng; Ruoming Ma; Chen Chen; Jusheng Bao; Xuchun Wang; You Liu

doi:10.1016/j.jcis.2023.08.158

Enhancing perovskite solar cells efficiency through cesium fluoride mediated surface lead iodide modulation

J Colloid Interface Sci. 2023 Dec 15;652(Pt B):1726-1733. doi: 10.1016/j.jcis.2023.08.158. Epub 2023 Aug 29.

Authors

Junming Chen¹, Kun Xu², Weicheng Xie², Lishuang Zheng², Yulu Tian², Jue Zhang², Jiahui Chen², Tianyuan Liu², Hanzhong Xu², Kun Cheng², Ruoming Ma², Chen Chen³, Jusheng Bao², Xuchun Wang⁴, You Liu⁵

Affiliations

¹ College of Chemistry and Materials Engineering, Anhui Science and Technology University, Bengbu, Anhui 233000, PR China; Anhui Province Quartz Sand Purification and Photovoltaic Glass Engineering Research Center, Chuzhou 233100, PR China.
² College of Chemistry and Materials Engineering, Anhui Science and Technology University, Bengbu, Anhui 233000, PR China.
³ National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, Jiangsu 210009, PR China.
⁴ College of Chemistry and Materials Engineering, Anhui Science and Technology University, Bengbu, Anhui 233000, PR China; Anhui Province Quartz Sand Purification and Photovoltaic Glass Engineering Research Center, Chuzhou 233100, PR China. Electronic address: wangxc@ahstu.edu.cn.
⁵ College of Chemistry and Materials Engineering, Anhui Science and Technology University, Bengbu, Anhui 233000, PR China; Anhui Province Quartz Sand Purification and Photovoltaic Glass Engineering Research Center, Chuzhou 233100, PR China. Electronic address: liuyou@ahstu.edu.cn.

PMID: 37672975
DOI: 10.1016/j.jcis.2023.08.158

Abstract

The presence of an excessive amount of lead iodide on the surface of perovskite solar cells (PSCs) is a significant contributing factor that adversely affects the stability of these devices when exposed to continuous light. To address this issue, we developed an effective strategy involving polishing PbI₂ on a perovskite surface using CsF. In this study, we investigated the effects of CsF post-treatment on perovskite films and their photovoltaic properties. The results of the time-resolved photoluminescence and ultraviolet photoelectron spectroscopy tests reveal the significant positive impact of our passivation method based on CsF, which reduces the valence band offset between the perovskite and hole transport layers while simultaneously enhancing the carrier interface transport. PSCs treated with CsF exhibited a photoelectric conversion efficiency (PCE) of 24.25% and an increased fill factor (FF) of 81.72%, which surpassed those of the original PSCs (PCE = 22.12% and FF = 77.40%). Furthermore, after aging for over 2500 h at room temperature and in 30 ± 10% humidity, the PCE of the unpacked PSCs reduced to only 42% of the initial value. Furthermore, the devices treated with CsF maintained their impressive performance, with the PCE maintaining optimal levels at 91% of the initial efficiency.

Keywords: Cesium fluoride; Perovskite solar cells; Post-treatment; Surface passivation.