Abstract The hole-transport material (HTM) free carbon-based perovskite solar cells (C–PSCs) lacks a HTM layer inside, resulting in poor charge transport performance. The power conversion efficiencies (PCE) of the C–PSCs could be effectively improved by increasing the transmission of photo-generated electrons from the perovskite to the electron transport layer. Here, the nanoparticles with TiO2@ PbTiO3 core-shell structure were prepared by in-situ reaction and used as mesoporous electron transport layer to improve electron transport performance. It is worth noting that the density of defect states on the surface of TiO2 significantly reduced due to the coating of PbTiO3, which effectively inhibits the interfacial charge recombination caused by the defect as the carrier recombination center. The electron injection from perovskite to electron transport layer enhanced ascribing to the optimized energy band arrangement. The open circuit voltage (Voc) and short circuit density (Jsc) were significantly improved, as well as the hysteresis retarded. Finally, the optimal PCE prepared in the air condition increased from 6.55% to 7.97%. This study provides a very feasible idea for obtaining high-performance C–PSCs.

中文翻译：

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TiO2@PbTiO3核壳纳米粒子作为介孔层提高碳基钙钛矿太阳能电池的电子传输性能

摘要 空穴传输材料 (HTM) 游离碳基钙钛矿太阳能电池 (C-PSCs) 内部缺乏 HTM 层，导致电荷传输性能较差。通过增加光生电子从钙钛矿到电子传输层的传输，可以有效提高 C-PSC 的功率转换效率（PCE）。在这里，通过原位反应制备了具有 TiO2@PbTiO3 核壳结构的纳米颗粒，并将其用作介孔电子传输层以提高电子传输性能。值得注意的是，由于PbTiO3的包覆，TiO2表面的缺陷态密度显着降低，有效抑制了缺陷作为载流子复合中心引起的界面电荷复合。由于优化的能带排列，从钙钛矿到电子传输层的电子注入增强。开路电压 (Voc) 和短路密度 (Jsc) 显着提高，滞后延迟。最后，在空调条件下制备的最佳PCE从6.55%提高到7.97%。该研究为获得高性能 C-PSC 提供了一个非常可行的想法。