Despite the rapid progress in device efficiency of the perovskite solar cells (PVSCs), the origin of commonly observed large variability of device performance from one-step to two-step approaches is still elusive. Herein, the processing windows of perovskite films prepared by one-step and two-step processes have been investigated. We find that both perovskite films prepared by one-step and two-step methods in air are much rougher than that prepared in glovebox. For the one-step method, complete perovskite conversion can be readily achieved both in air and in glovebox, but totally different in surface morphology. For the two-step method, residual PbI₂ are remained in perovskite film, particularly with larger amount for the film prepared in air. Both rough surface and incomplete conversion hinder the realization of high quality perovskite film in air. The photovoltaic performances of the PVSCs prepared by one-step and two-step methods in glovebox are systematically compared. The generally observed lower photovoltaic performance of two-step PVSCs is ascribed to the additional trap-assisted recombination process due to larger trap density in the two-step perovskite film. This is confirmed by carrier recombination study using steady state photoluminescence, transient photovoltage and photocurrent measurements. Finally, combining the high work function hole transporting material poly-TPD, and the high-quality one-step perovskite film, a 17.5% high-efficiency PVSCs can be achieved. The results reveal the major impacts on the morphological and electronic properties of perovskite films between one-step and two-step method, and it brings insight into the strategy for extending the processing windows to achieve highly reliable PVSCs.

尽管钙钛矿型太阳能电池（PVSC）的器件效率迅速提高，但是从一步到两步的方法中，通常观察到的器件性能的巨大差异仍然难以捉摸。在本文中，已经研究了通过一步法和两步法制备的钙钛矿膜的加工窗口。我们发现，通过一步法和两步法在空气中制备的钙钛矿薄膜都比在手套箱中制备的钙钛矿薄膜更粗糙。对于一步法，无论是在空气中还是在手套箱中都可以轻松实现钙钛矿的完全转化，但是表面形态却完全不同。对于两步法，残留PbI ₂残留在钙钛矿薄膜中，尤其是在空气中制备的薄膜中。粗糙的表面和不完全的转化都阻碍了空气中高质量钙钛矿薄膜的实现。系统地比较了在手套箱中一步法和两步法制备的PVSC的光伏性能。由于两步钙钛矿膜中较大的陷阱密度，通常观察到的两步PVSC较低的光伏性能归因于额外的陷阱辅助重组过程。通过使用稳态光致发光，瞬态光电压和光电流测量的载流子复合研究已证实了这一点。最后，将高功函数空穴传输材料poly-TPD和高质量的一步钙钛矿薄膜相结合，可以实现17.5％的高效PVSC。