Pseudo-halide anion engineering for efficient quasi-2D Ruddlesden-Popper tin perovskite solar cells
Pseudo-halide anion engineering for efficient quasi-2D Ruddlesden-Popper tin perovskite solar cells
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DOI：
10.1016/j.xcrp.2022.101060
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发表时间：
2022-09
影响因子：
8.9
通讯作者：
Hao Li;Yuanze Xu;Shripathi Ramakrishnan;Yugang Zhang;M. Cotlet;Tony Lou Xu;Qiuming Yu
中科院分区：
文献类型：
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作者：
Hao Li;Yuanze Xu;Shripathi Ramakrishnan;Yugang Zhang;M. Cotlet;Tony Lou Xu;Qiuming Yu
准二维（2D）有机-无机杂化锡钙钛矿由于其降低的毒性和改善的稳定性而成为薄膜光致发光材料中铅基钙钛矿的有希望的替代物。然而，由于不可控的成核和晶体生长过程，不期望的小n值2D相和无序的晶体取向极大地限制了准2D锡钙钛矿太阳能电池（PSC）的效率。在这里，我们提出了一种混合的拟卤化物阴离子工程方法，通过使用乙酸根（Ac-）和四氟硼酸根（BF 4-）阴离子来制造准2D Ruddlesden-Popper钙钛矿，目标分子式为PEA 2FA 4Sn 5I 16。我们发现，混合的Ac−和BF 4 −阴离子不仅可以通过有效地打破PEA+···PEA+堆积来促进PEA+阳离子在前驱体中均匀分布，而且还可以通过与未键合的SnI 2配位来延缓结晶过程，从而显著减少小n值2D相，改善晶体取向，并抑制Sn 2+氧化。由此产生的PSC具有高达9%的功率转换效率和400小时的稳定性。
Quasi-two-dimensional (2D) organic-inorganic hybrid tin perovskites have emerged as promising alternatives to lead-based perovskites in thin-film photovoltaics because of their reduced toxicity and improved stability. However, the undesired small n-value 2D phases and disordered crystal orientation enormously restrict the efficiency of quasi-2D tin perovskite solar cells (PSCs) due to uncontrollable nucleation and crystal growth processes. Here, we propose a mixed pseudo-halide anion engineering approach by using acetate (Ac−) and tetrafluoroborate (BF4−) anions to make quasi-2D Ruddlesden-Popper perovskites with a target formula of PEA2FA4Sn5I16. We find that the mixed Ac−and BF4−anions can not only promote homogeneously distributed PEA+cations in the precursor by effectively breaking the PEA+···PEA+stacking but also retard the crystallization process by coordinating with unbonded SnI2, thereby, significantly reducing small n-value 2D phases, improving the crystal orientation, and suppressing the Sn2+oxidation. The resulting PSC exhibits up to 9% power conversion efficiency and 400 h stability.