Carbon quantum dots passivated CsPbBr3 film with improved water stability and photocurrent: Preparation, characterization and application

All-inorganic cesium lead perovskite quantum dots (PQDs) with excellent optical properties have obtained extensive study in the field of optoelectronics . However, the poor stability of CsPbBr 3 in the atmosphere and water severely limits their practical application. In this work, carbon quantum dots (CQDs) were exploited as dopants to improve the aqueous stability and photo-induced charge transfer properties of CsPbBr 3 . A highly fluorescent and aqueous stable film, consisting of CQDs-CsPbBr 3 embedded in polyvinylidene fluoride (PVDF) polymer, was obtained by a simple spin coating method. Experiment results showed that the fluorescence (FL) intensity of CQDs-CsPbBr 3 @PVDF film retained about 85% of its initial value after being soaked in water for 50 days, indicating the good water stability of CQDs doped CsPbBr 3 . Besides, the photocurrent of CsPbBr 3 film increased from 0.1 μA to 0.9 μA after doping CQDs under light irradiation, which proved that the improved charge transfer of CsPbBr 3 was beneficial from CQDs. The application of CQDs-CsPbBr 3 @PVDF film in down-converted light emitting diodes has also been checked. This work highlighted one application of CQDs for improving the performances of PQDs in the field of optoelectronics.