The morphology of perovskite thin films in the planar heterojunction configuration is of prime importance to achieve highly efficient and reproducible photovoltaic devices. However, when deposited by the two-step method, simple solution processing results in adverse surface properties, hampering the controlled preparation of high quality absorber layers. We show that by the deliberate choice of solvents regarding the alcoholic conversion solution, the surface morphology can be finely tuned resulting in compact films with large grain sizes comparable to that of vapor assisted methods. It was found that the permittivity of the solvent is the main parameter affecting the crystallization and grain size. The strategy provides a simple way to achieve desirable surface properties by simple and cheap solution processing.

平面异质结构型的钙钛矿薄膜的形态对于实现高效且可重现的光伏器件至关重要。然而，当通过两步法沉积时，简单的溶液处理导致不利的表面性质，从而妨碍了高质量吸收层的受控制备。我们表明，通过有选择地选择关于酒精转化溶液的溶剂，可以对表面形态进行微调，从而形成具有与蒸汽辅助法相当的大晶粒尺寸的致密薄膜。发现溶剂的介电常数是影响结晶和晶粒尺寸的主要参数。该策略提供了一种简单的方法，可通过简单且廉价的溶液处理来获得所需的表面性能。