Improved comprehensive performance of CsPbI2Br perovskite solar cells by modifying the photoactive layers with carbon nanodots

Introducing additives into perovskite layers is an effective method to enhance the power conversion efficiency (PCE) and operation stability of perovskite solar cells (PSCs). Herein, we reported an addition of carbon nanodots (CNDs) into the CsPbI2Br photoactive layer to boost performance of the related PSCs. It is found that the trap density can be notably suppressed, and the crystallinity can be enhanced after introducing CNDs with an optimal quantity. The PSC with 1.0 wt% addition of CNDs delivers a notable improved average PCE of 13.77% (the highest PCE: 14.69%) from that of 12.14% for the control device without CND addition. Moreover, the CND-added CsPbI2Br PSCs exhibit superior stability, i.e., ∼86 % retention of the initial PCE after 160 h aging in air with the humidity of 20%–30%, to the control device.