Dynamic manipulation of crystallization is pivotal to the quality of polycrystalline films. A molten-salt-assisted crystallization (MSAC) strategy is presented to improve grain growth of the all-inorganic perovskite films. Compared with the traditional solvent annealing, MSAC enables more intensive mass transfer by means of convection and diffusion, which is beneficial to the interaction among the precursor colloids and to inducing in-plane growth of perovskite grains, resulting in the formation of high-quality perovskite films with suppressed pinhole and crack formation. Additionally, the introduction of molten salt alters the intermediate phases, and thus changes the crystallization pathways by reducing the energy barrier to produce films with desired optical and electrical properties. As a result, the MSAC strategy endows the devices with champion steady-state output efficiency of 19.83% and open-circuit voltage (V_oc) as high as 1.2 V, among the highest for this type of solar cell, thanks to its effectively reduced V_oc deficit.

中文翻译：

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熔盐辅助 CsPbI3 钙钛矿结晶，用于效率接近 20% 的太阳能电池

结晶的动态控制对多晶薄膜的质量至关重要。提出了一种熔盐辅助结晶（MSAC）策略来改善全无机钙钛矿薄膜的晶粒生长。与传统的溶剂退火相比，MSAC通过对流和扩散的方式实现了更强烈的传质，有利于前驱体胶体之间的相互作用和诱导钙钛矿晶粒的面内生长，从而形成高质量的钙钛矿具有抑制针孔和裂纹形成的薄膜。此外，熔盐的引入改变了中间相，从而通过降低能垒来改变结晶途径，从而产生具有所需光学和电学特性的薄膜。其结果，V _oc ) 高达 1.2 V，是此类太阳能电池中最高的，这要归功于其有效降低了V _oc赤字。