Controlled functionalization of 2D black phosphorus (BP) nanosheets provides unique opportunities to tune their chemical, physical, and electronic properties. Herein, the preparation of single-atom nickel-doped BP (Ni–BP) sheets using a simple solution-based strategy is reported. Using the Ni–BP sheets as a passivation layer on top of a perovskite film leads to standard perovskite solar cells (PSCs) with improved performance. The standard n–i–p PSCs with the Ni–BP interlayer achieve maximum power conversion efficiencies of over 22%, with negligible hysteresis and a modest improvement in stability when subjected to different testing conditions. The perovskite films prepared with Ni–BP sheets-based passivation are found to have reduced defect densities as well as improved charge-transfer properties and carrier lifetimes. Density-functional theory calculations support the experimental results through showing that the atomic Ni-doping increases the work function of the BP interlayer, enabling better hole extraction, as well as increasing the surface hydrophobicity of the BP layer, hence reducing water sorption into the perovskite film.

中文翻译：

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用于高效稳定钙钛矿太阳能电池的原子掺杂二维黑磷

二维黑磷 (BP) 纳米片的受控功能化为调整其化学、物理和电子特性提供了独特的机会。本文报道了使用简单的基于溶液的策略制备单原子镍掺杂 BP (Ni-BP) 片材。使用 Ni-BP 片作为钙钛矿薄膜顶部的钝化层可以提高标准钙钛矿太阳能电池（PSC）的性能。具有 Ni-BP 中间层的标准 n -i- p PSC 可实现超过 22% 的最大功率转换效率，在不同的测试条件下，滞后现象可以忽略不计，稳定性也有一定的提高。研究发现，采用 Ni-BP 片材钝化制备的钙钛矿薄膜可以降低缺陷密度，并提高电荷转移性能和载流子寿命。密度泛函理论计算显示原子 Ni 掺杂增加了 BP 中间层的功函数，从而实现更好的空穴提取，并增加了 BP 层的表面疏水性，从而减少了钙钛矿的水吸附，从而支持了实验结果电影。