Laser induced anti-solvent carbon quantum dots in defect passivation for effective perovskite solar cells

In this study, anti-solvent carbon quantum dots (ASCQDs), generated via pulsed laser irradiation in chlorobenzene (CB), were adopted as an additive for defect passivation of the grain boundaries of CH 3 NH 3 PbI 3 in hole-conductor-free, carbon-counter-electrode perovskite solar cells (PSCs). The size of the ASCQDs can be easily regulated by different laser fluence. The improvement of perovskite films’ morphology was revealed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), which was beneficial for carrier transport. Higher photoluminescence (PL) intensity as well as prolonged carrier lifetime were proved in the ASCQDs optimized perovskite film, confirmed the laser induced ASCQDs can decrease nonradiative recombination via defect passivation, which can be further verified by the decreased defect density . As a result, the introduction of ASCQDs (1064 nm-50 mJ pulse −1 cm −1 -10 min) led to a champion efficiency of 14.95%, which improved 14.04% when compared with pure CB treated PSCs (13.11%). Furthermore, the ASCQDs treated PSCs can still retain 93% and 81% of the initial power conversion efficiency after 600 h in the glovebox and in the atmosphere with humidity of 50–70%, respectively.