Understanding the double-edged-sword effect of dimethyl sulfoxide to guide the design of highly efficient perovskite solar cells in humid air

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) is comparable to that of silicon cells, and their commercialization is just around the corner. However, a harsh environment greatly increases their cost, and preparing high-performance PSCs in humid air without a strictly controlled environment will dominate future research directions. Previous works have made many efforts to overcome problems associated with the moisture in humid air, and some additives or preparation technologies have been proposed. However, the mechanism for how H2O influences the device performance is not very clear. In this work, based on the most commonly used perovskite system with a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), we conclude that the DMSO solvent exhibits a double-edged sword effect in preparing a perovskite film in humid air, and we achieve a high-quality perovskite film based on this understanding. Unencapsulated PSCs exhibit competitive PCEs under almost any humidity level, and a PCE exceeding 23% can be achieved without the need for any additives at medium humidity. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Humidity has a significant impact on the performance of perovskite solar cells, and preparing high-performance cells in humid air is a future research direction. It has been found that the DMSO solvent in humid air has a double-edged sword effect, enabling the preparation of high-quality perovskite films.