Engineering CsPbBr3 quantum dots with efficient luminescence and stability by damage-free encapsulation with a-SiCx:H

Abstract

Although encapsulation is an effective technique to improve the stability of perovskite quantum dots (PQDs), they are prone to photoluminescence (PL) degradation during encapsulation. Herein, a damage-free plasma-based encapsulation technique in combination with real-time in situ diagnosis is designed for CsPbBr3 QDs films. The CH4/SiH4 plasma has little destructive effects on the CsPbBr3 QDs. The a-SiCx:H films prepared with the CH4/SiH4 plasma by low-temperature plasma-enhanced chemical vapor deposition protect the CsPbBr3 QDs from surface damage during encapsulation, so that the intrinsic PL efficiency is maintained. Furthermore, the PL intensity is improved by increasing the carbon concentration in a-SiCx:H and the CsPbBr3 QDs films encapsulated by a-SiCx:H show long term stability under harsh conditions such as prolonged air exposure, UV light illumination for more than 60 days, immersion in water, as well as thermal treatment at 205 oC.