Suppression of the Marangoni effect by controlling the mixing procedures of the precursor solution to improve the performance of perovskite solar cells

Abstract

Perovskite solar cells (PSCs) with mesoporous structures have attracted much attention due to their stability and low cost. In this work, we found that the preparation procedures of the precursor solutions directly affect their permeability in the mesoporous scaffold with a mixed solvent system consisting of γ-valerolactone (GVL) and ethanol (EtOH). Control over the side reactions in the precursor solution can suppress the Marangoni effect. The optimized solution can uniformly penetrate the mesoporous scaffold, which can enhance the interfacial contact and charge transfer well, thus significantly improving the photovoltaic performance of the PSCs. This process significantly improved the power conversion efficiency (PCE) from 14.71% to 16.55% (mask area of 0.07 cm²). A PCE of 13.02% was achieved for a large-area sub-module with an effective area of 66 cm². In addition, the unencapsulated PSCs obtained using the optimized solution showed better stability with less than 15% decay over 1440 hours of storage in air (25–35% RH).