One-Step Preparation of Long-Term Stable and Flexible CsPbBr Perovskite Quantum Dots/Ethylene Vinyl Acetate Copolymer Composite Films for White Light-Emitting Diodes.

CsPbBr perovskite quantum dots (PQDs)/ethylene vinyl acetate (EVA) composite films were prepared via a one-step method; on the basis of this, both supersaturated recrystallization of CsPbBr PQDs and dissolution of EVA were realized in toluene. The prepared films display outstanding green-emitting performance with high color purity of 92% and photoluminescence (PL) quantum yield of 40.5% at appropriate CsPbBr PQD loading. They possess long-term stable luminescent properties in the air and in water, benefiting from the effective protection of CsPbBr PQDs by the EVA matrix. Besides, the prepared CsPbBr PQDs/EVA films are flexible enough to be repeatedly bent for 1000 cycles while keeping unchanged the PL intensity. The optical properties of the CsPbBr PQDs/EVA films in white light-emitting diodes were also studied by experiments and theoretical simulation. Overall, facile preparation process, good long-term stability, and high flexibility allow our green-emitting CsPbBr PQDs/EVA films to be applied in lighting applications and flexible displays.