Effective Inhibition of Phase Segregation in Wide‐Bandgap Perovskites with Alkali Halides Additives to Improve the Stability of Solar Cells. Issue 5 (18th January 2023)

• Record Type: Journal Article
• Authors: Meng, Xin; Wang, Jianan; Wang, Haixin; Li, Mengjie; Sun, Derun; Hu, Xiaodong; He, Jizhou; Yu, Peng; Zhou, Jing; Chen, Rui; Ren, Fumeng; Liu, Sanwan; Zhang, Shasha; Zhang, Yiqiang; Zhao, Zhiguo; Liu, Zonghao; Chen, Wei
• Is Part Of: Solar RRL. Volume 7:Issue 5(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-01-18
• Subjects: additive strategy -- alkali halides -- phase segregation -- photostability -- wide-bandgap perovskites; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.202201099
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : Wide‐bandgap perovskites have attracted much attention due to their potential application in perovskite‐based tandem solar cells, which can surpass the theoretical efficiency up‐limit of single‐junction solar cells. However, photoinduced phase segregation remains one of the most intractable impediments that deteriorate the operational stability of wide‐bandgap perovskites solar cells. Herein, the effect of a series of alkali halides additives on the photoinduced phase segregation of wide‐bandgap perovskites with the composition of FA0.8 Cs0.2 Pb(I0.7 Br0.3 )3 (FA is formamidinium) is systematically studied. By coupling in situ time‐dependent photoluminescence technique, potassium chloride (KCl) is demonstrated to be the best in suppressing the photoinduced phase segregation. The reduced iodine vacancy defects owing to supplemented chloride ions and the coupling of potassium ions with the accumulated iodide ions at the grain boundaries lead to effective suppression phase segregation. As a consequence, the KCl‐modified wide‐bandgap perovskite solar cells present a champion efficiency of 19.34%, and the devices can maintain 93% of the initial efficiency after light soaking for 500 h with maximum power point tracking under 1 sun equivalent white light‐emitting diode illumination, much superior to the reference device without KCl modification only retaining 72% of its initial efficiency. Abstract : Wide‐bandgap perovskite (FA0.8 Cs0.2 Pb(I0.7 Br0.3 )3 shows significant potential in perovskite‐based tandem solar cells. Nevertheless, photoinduced phase segregation is an obstacle that needs to be resolved urgently. It is revealed that the potassium chloride additive can suppress phase segregation optimally by pairing the excess iodide ions around the grain boundaries. Consequently, the efficiency of KCl‐modified wide‐bandgap devices is improved from 17.18% to 19.34%.