All-Inorganic Perovskite Quantum Dots/p-Si Heterojunction Light-Emitting Diodes under DC and AC Driving Modes

摘要

Light-emitting diodes based on perovskite quantum dots have attractedrnmuch attention since they can be applied in low-cost display, biosensors,rnand other optoelectronic devices. Here, all-inorganic light-emitting diodesrnbased on n-type perovskite quantum dots/p-Si heterojunction are fabricated.rnBoth the green and the red light emission are achieved at room temperature.rnThe output power density is 0.14 mW cm~(−2) for green light device andrn0.25 mW cm~(−2) for the red one. The relatively low turn on voltage and highrnemission intensity in red light device can be attributed to the small hole injectionrnbarrier between CsPbI_3 quantum dots and p-Si. The emission drop offrnat high current density is observed under direct current (DC) driving mode,rnwhich is significantly improved by applying alternating current (AC) squarernpulses. The enhanced electroluminescence and the improved operationrnstability at high current density under AC driving mode can be attributed tornthe less thermal degradation and the reduced charge accumulation in therninterface defect states due to the alternated biases. The results demonstraternthe possibility of integrating the perovskite quantum dots with Si platform,rnwhich will be helpful to extend their actual applications.