Enhanced Photoresponsivity of All-Inorganic (CsPbBr3) Perovskite Nanosheets Photodetector with Carbon Nanodots (CDs)

A hybrid composite photodetector based on cesium lead bromine perovskite (CsPbBr3) nanosheets and carbon nanodots (CDs) was fabricated on a quartz substrate by a one-step method of spin-coating and hot-plate annealing. The responsivity of the CsPbBr3/CD hybrid composite photodetector was 608 mAW(-1) (under a 520-nm laser diode source applied at 0.2 mWcm(-2)), almost three times higher than that of a CsPbBr3-based photodetector (221 mAW(-1)). The enhanced performance of the CsPbBr3/CD photodetector is attributable to the high band alignment of the CDs and CsPbBr3, which significantly improves the charge extraction at the CsPbBr3/CD interface. Moreover, the hybrid CsPbBr3/CD photodetector exhibited a fast response time with a rise and decay time of 1.55 and 1.77 ms, which was faster than that of a pure CsPbBr3 based photodetector, indicating that the CDs accelerate the extraction of electrons and holes trapped in the CsPbBr3 film.