Halide Diffusion Equilibrium and Its Impact on Efficiency Evolution of Perovskite Solar Cells. Issue 48 (17th October 2022)

• Record Type: Journal Article
• Authors: Li, Qing; Zheng, Yichu; Wei, Zhanpeng; Xie, Jin; Zou, Can; Liu, Xinyi; Liu, Da; Zhou, Ziren; Yang, Hua Gui; Yang, Shuang; Hou, Yu
• Is Part Of: Advanced energy materials. Volume 12:Issue 48(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-17
• Subjects: chemical doping -- halides diffusion equilibrium -- perovskite solar cells -- power conversion efficiency -- transport layers; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.202202982
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: Understanding the degradation mechanism of perovskite solar cells (PSCs) is of particular importance to solve their instability issue, which is one of the major hindrances toward commercialization. Here, it is shown that a halide diffusion equilibrium exists at the heterointerface of perovskite devices, which strongly impacts the evolution of device performance. The combined experimental and theoretical studies reveal that halide components diffuse from perovskite to fullerene layers in a p‐i‐n PSC device and equilibrate with an iodine density of 10 18 –10 19 cm −3 within 80 h under dark aging condition. It is found that there is a strong correction between the device efficiency and halide diffusion equilibrium of PSCs, as the diffused halides can chemically dope the transport layer and result in the nonstoichiometric perovskite surface, leading to both initial enhancement and long‐term loss of the photovoltaic efficiency of solar cells. In response to this issue, a predoping strategy is developed to attain the halide diffusion equilibrium once the device is fabricated, thereby avoiding the further halide migration and initial efficiency variations. As a result, the as‐prepared PSC achieved an efficiency of 23.13% as well as stable power output under continuous one sun illumination. Abstract : The halide diffusion from perovskite can chemically dope the electron transport layer and bring forth the nonstoichiometric surface, leading to initial enhancement but long‐term loss of the photovoltaic efficiency of p‐i‐n cells. A predoping strategy is developed to reach the diffusion equilibrium state for the fresh‐fabricated device and delivers a power conversion efficiency of 23.13% with stable power output.