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3D–2D–0D Interface Profiling for Record Efficiency All‐Inorganic CsPbBrI 2 Perovskite Solar Cells with Superior Stability
Author(s) -
Zhang Jingru,
Bai Dongliang,
Jin Zhiwen,
Bian Hui,
Wang Kang,
Sun Jie,
Wang Qian,
Liu Shengzhong Frank
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201703246
Subject(s) - materials science , heterojunction , energy conversion efficiency , perovskite (structure) , optoelectronics , band gap , perovskite solar cell , nanosheet , photovoltaic system , quantum dot , nanotechnology , chemical engineering , electrical engineering , engineering
All‐inorganic CsPbBrI 2 perovskite has great advantages in terms of ambient phase stability and suitable band gap (1.91 eV) for photovoltaic applications. However, the typically used structure causes reduced device performance, primarily due to the large recombination at the interface between the perovskite, and the hole‐extraction layer (HEL). In this paper, an efficient CsPbBrI 2 perovskite solar cell (PSC) with a dimensionally graded heterojunction is reported, in which the CsPbBrI 2 material is distributed within bulk–nanosheet–quantum dots or 3D–2D–0D dimension‐profiled interface structure so that the energy alignment is optimized in between the valence and conduction bands of both CsPbBrI 2 and the HEL layers. Specifically, the valence‐/conduction‐band edge is leveraged to bend with synergistic advantages: the graded combination enhances the hole extraction and conduction efficiency with effectively decreased recombination loss during the hole‐transfer process, leading to an enhanced built‐in electric field, hence a high V OC of as much as 1.19 V. The profiled structure induces continuously upshifted energy levels, resulting in a higher J SC of as much as 12.93 mA cm −2 and fill factor as high as 80.5%, and therefore record power conversion efficiency (PCE) of 12.39%. As far as it is known, this is the highest PCE for CsPbBrI 2 perovskite‐based PSC.