Browsing by Author "Liu, Hairui"

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    Ionic liquid Stabilizing high‐efficiency tin halide perovskite solar cells
    (2021) Li, Guixiang; Su, Zhenhuang; Li, Meng; Yang, Feng; Aldamasy, Mahmoud H.; Pascual, Jorge; Yang, Fengjiu; Liu, Hairui; Zuo, Weiwei; Di Girolamo, Diego; Iqbal, Zafar; Nasti, Giuseppe; Dallmann, André; Gao, Xingyu; Wang, Zhaokui; Saliba, Michael; Abate, Antonio
    Tin halide perovskites attract incremental attention to deliver lead‐free perovskite solar cells. Nevertheless, disordered crystal growth and low defect formation energy, related to Sn(II) oxidation to Sn(IV), limit the efficiency and stability of solar cells. Engineering the processing from perovskite precursor solution preparation to film crystallization is crucial to tackle these issues and enable the full photovoltaic potential of tin halide perovskites. Herein, the ionic liquid n‐butylammonium acetate (BAAc) is used to tune the tin coordination with specific O…Sn chelating bonds and NH…X hydrogen bonds. The coordination between BAAc and tin enables modulation of the crystallization of the perovskite in a thin film. The resulting BAAc‐containing perovskite films are more compact and have a preferential crystal orientation. Moreover, a lower amount of Sn(IV) and related chemical defects are found for the BAAc‐containing perovskites. Tin halide perovskite solar cells processed with BAAc show a power conversion efficiency of over 10%. This value is retained after storing the devices for over 1000 h in nitrogen. This work paves the way toward a more controlled tin‐based perovskite crystallization for stable and efficient lead‐free perovskite photovoltaics.
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    Pure tin halide perovskite solar cells : focusing on preparation and strategies
    (2022) Liu, Hairui; Zhang, Zuhong; Zuo, Weiwei; Roy, Rajarshi; Li, Meng; Byranvand, Mahdi Malekshahi; Saliba, Michael
    Metal halide perovskite solar cells (PSCs) have emerged as an important direction for photovoltaic research. Although the power conversion efficiency (PCE) of lead‐based PSCs has reached 25.7%, still the toxicity of Pb remains one main obstacle for commercial adoption. Thus, to address this issue, Pb‐free perovskites have been proposed. Among them, tin‐based perovskites have emerged as promising candidates. Unfortunately, the fast oxidation of Sn2+ to Sn4+ leads to low stability and efficiency. Many strategies have been implemented to address these challenges in Sn‐based PSCs. This work introduces stability and efficiency improvement strategies for pure Sn‐based PSCs by optimization of the crystal structure, processing and interfaces as well as, implementation of low‐dimension structures. Finally, new perspectives for further developing Sn‐based PSCs are provided.