Morphology and crystallinity of perovskite layers are crucial for power conversion efficiency (PCE) of perovskite solar cells (PSCs). Here, we introduced amorphous polymer polyvinylpyrrolidone (PVP) with a CO functional group into a CH₃NH₃PbI_3−xCl_x perovskite precursor to tune the morphology and crystallinity of perovskite layers during the film formation process. The spreading amorphous polymer chains and excellent hygroscopicity of PVP can help the perovskite precursor have better contact with the substrate, leading to better perovskite film coverage. More importantly, the electron pair existing in the oxygen atom of the CO bond in PVP has a strong attraction to Pb(II) ions, which can adjust the location of the nuclei and make the nuclei distribute uniformly in PVP chains, contributing to a uniform and compact perovskite layer. As a result, perovskite films with PVP present favourable morphology and improved crystallinity. The performance of a CH₃NH₃PbI_3−xCl_x-based perovskite solar cell with optimized PVP content achieves a summit PCE of 16.57% with photovoltage V_OC of 1057 mV, short circuit current density J_SC of 21.38 mA cm⁻², and fill factor FF of 74.52% under standard AM 1.5 solar light of 100 mW cm⁻² intensities, which demonstrates a 23.9% increment compared with a PCE of 13.37% of the original device.

中文翻译：

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具有C O的非晶态聚合物可改善钙钛矿太阳能电池的性能

钙钛矿层的形态和结晶度对于钙钛矿太阳能电池（PSC）的功率转换效率（PCE）至关重要。在这里，我们将具有C O官能团的无定形聚合物聚乙烯吡咯烷酮（PVP）引入CH ₃ NH ₃ PbI _{3- x} Cl _x钙钛矿前体中，以调节膜形成过程中钙钛矿层的形貌和结晶度。散布的无定形聚合物链和出色的PVP吸湿性可以帮助钙钛矿前体与基材更好地接触，从而导致更好的钙钛矿膜覆盖。更重要的是，PVP中C O键的氧原子中存在的电子对对Pb具有很强的吸引力（II离子，可以调节原子核的位置并使原子核在PVP链中均匀分布，从而形成均匀而致密的钙钛矿层。结果，具有PVP的钙钛矿膜呈现出良好的形态和改善的结晶度。具有优化的PVP含量的基于CH ₃ NH ₃ PbI _{3- x} Cl _x的钙钛矿太阳能电池的性能实现了16.57％的峰PCE，光电压V _OC为1057 mV，短路电流密度J _SC为21.38 mA cm ^-2。，并且在100 mW cm ^-2的标准AM 1.5太阳光下，填充系数FF为74.52％ 强度，与原始设备的13.73％的PCE相比，表明增加了23.9％。