掺杂质子化石墨相氮化碳增强碳基太阳能电池中钙钛矿的结晶

钙钛矿层的品质极大影响钙钛矿太阳能电池性能. 然而，在溶液法生成多晶钙钛矿膜过程中会不可避免地形成缺陷和陷阱位. 通过在钙钛矿层中嵌入添加物改善钙钛矿晶化，用于减少和钝化缺陷是非常重要的. 本文合成一种环境友好的二维纳米材料质子化石墨相氮化碳(p-g-C₃N₄)，并掺杂于碳基钙太阳能电池的钙钛矿层中. 实验证明，在钙钛矿前驱体溶液中添加p-g-C₃N₄不仅能调解碘铅甲胺(MAPbI₃)结晶的成核和生长速率，获得大晶粒尺寸的平滑表面，还能减少钙钛矿层的本征缺陷. 质子化过程在氮化碳表面引入活性基团-NH₂/-NH₃，它们和钙钛矿晶体表面N-H键发生强化学作用，有效地钝化电子陷阱，提高钙钛矿结晶质量. 结果表明，与不掺杂的对照电池(效率为4.48%)和掺杂石墨相氮化碳(g-C₃N₄)电池(效率为5.93%)相比，掺杂质子化石墨相氮化碳(p-g-C₃N₄)的电池获得了6.61%的较高效率. 本工作展示了一种通过掺杂改性添加物改善钙钛矿膜的简单方法，为碳基钙钛矿太阳能电池的低成本制备提供了建议.

Enhanced Crystal Quality of Perovskite via Protonated Graphitic Carbon Nitride Added in Carbon-Based Perovskite Solar Cells

The quality of perovskite layers has a great impact on the performance of perovskite solar cells (PSCs). However, defects and related trap sites are generated inevitably in the solutionprocessed polycrystalline perovskite films. It is meaningful to reduce and passivate the defect states by incorporating additive into the perovskite layer to improve perovskite crystallization. Here an environmental friendly 2D nanomaterial protonated graphitic carbon nitride (p-g-C₃N₄) was successfully synthesized and doped into perovskite layer of carbon-based PSCs. The addition of p-g-C₃N₄ into perovskite precursor solution not only adjusts nucleation and growth rate of methylammonium lead tri-iodide (MAPbI₃) crystal for obtaining flat perovskite surface with larger grain size, but also reduces intrinsic defects of perovskite layer. It is found that the p-g-C₃N₄ locates at the perovskite core, and the active groups -NH₂/NH₃ and NH have a hydrogen bond strengthening, which effectively passivates electron traps and enhances the crystal quality of perovskite. As a result, a higher power conversion efficiency of 6.61% is achieved, compared with that doped with g-C₃N₄ (5.93%) and undoped one (4.48%). This work demonstrates a simple method to modify the perovskite film by doping new modified additives and develops a low-cost preparation for carbon-based PSCs.