A research group led by Prof. LIU Shengzhong from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, in collaboration with YANG Dong from Shaanxi Normal University, reported high efficiency flexible perovskite solar cells using additive assistant strategy.

Flexible solar cells are lightweight, more portable, rollable, and easier to package, store, transport and install. The low temperature interface layer and high quality of perovskite absorber layer play key roles in flexible perovskite solar cells.

Illustration of the F-PSC structure and J–V curves of F-PSCs under reverse scan directions using MAPbI₃ and MAPbI₃–DS as the absorber layer. (Image by DUAN LianJie and YANG Dong)

The researchers used a new additive dimethyl sulfide to improve the quality of perovskite absorber. The research revealed that dimethyl sulfide could effectively enhance the perovskite grain size, improve crystalline, and reduce the trap density of perovskite film.

As a result, the efficiency of flexible perovskite solar cells was improved to 18.40% for small area cells (0.052cm²), and 13.35% for large area (1.2cm²) ones, both were the record-efficiencies for the flexible perovskite solar cells for their respective categories.

Meanwhile, the stability of flexible perovskite solar cells was also improved when using the dimethyl sulfide additive. The efficiency of the flexible device with the additive maintained 86% of its initial efficiency when stored in ambient at about 35% humidity after 60 days, while the flexible cells without additive degraded by 50% when stored under the same condition.

Their findings, published in Advanced Materials, help guide development of high efficiency flexible perovskite solar cells for practical applications.

The research was supported by the National Key Research and Development Program of China, National Natural Science Foundation of China, National University Research Fund, the 111 Project, and the Chinese National 1000 Talents Plan program.