The two-step deposition method effectively mitigates the efficiency decline observed in tin-based perovskite solar cells (TPVSCs) with increasing cell area, stemming from film in-homogeneity. However, the high solubility of SnI2 in the conventionally used solvent isopropyl alcohol, coupled with the absence of effective modulation of reaction-diffusion process, results in inadequate film coverage and conversion. In this study, we introduce formic acid as the second-step solvent and introduce dithiothreitol (DTT) to regulate reaction-diffusion/crystallization kinetics meticulously. Moreover, this research underscores a fundamental principle that the suitable binding energy ranging from -1.38 to -10.10 kcal/mol between ligands and Sn2+ significantly enhances the effectiveness of two-step crystallization control. Notably, a uniform perovskite film is achieved on large-scale substrate, and TPVSCs processed with DTT exhibit the highest efficiencies of 12.68% for 0.04 cm2 device and 11.30% for 1 cm2 device among tin-based perovskite devices in two-step sequential deposition method, even in the absence of dimethyl sulfoxide. This study lays the groundwork for the potential scale-up development of lead-free perovskite solar cells.

中文翻译：

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通过还原气氛对两步沉积锡基钙钛矿薄膜的反应-扩散和结晶动力学调控


两步沉积方法有效地减轻了在锡基钙钛矿太阳能电池 （TPVSC） 中观察到的效率下降，随着电池面积的增加，这源于薄膜的不均匀性。然而，SnI2 在常规使用的溶剂异丙醇中的高溶解度，加上缺乏对反应扩散过程的有效调节，导致薄膜覆盖和转化率不足。在本研究中，我们引入甲酸作为第二步溶剂，并引入二硫苏糖醇 （DTT） 来精心调节反应扩散/结晶动力学。此外，本研究强调了一个基本原理，即配体和 Sn2+ 之间合适的结合能范围为 -1.38 至 -10.10 kcal/mol 可显着提高两步结晶控制的有效性。值得注意的是，在大规模衬底上实现了均匀的钙钛矿薄膜，用 DTT 加工的 TPVSCs 在两步顺序沉积法中表现出 12.68% 的 0.04 cm2 器件和 11.30% 的锡基钙钛矿器件的效率，即使在没有二甲基亚砜的情况下也是如此。这项研究为无铅钙钛矿太阳能电池的潜在规模化开发奠定了基础。