Tunable Carbon–CsPbI3 Quantum Dots for White LEDs

Abstract

In this work, a simple method to prepare white light emissive diodes based on quantum dot (QD) colloidal solutions using mixed carbon QDs (CQDs) and CsPbI3 perovskite (PQDs) is reported. The right combination generates emission across the entire visible spectrum upon ultraviolet excitation. The white light emission of the final films provides high and stable color rendering index of 92%, tuning the chromaticity coordinates of the emission through the applied voltage. By varying the CsPbI3 QD concentration, a mixture is obtained that emits the “warm”, “neutral”, and “cold” white light sought for many indoor lighting applications, or to approximate the visible region of the solar spectrum, respectively. Remarkably, the material syntheses are low cost and truly scalable. In addition, colloidal mixtures of CQDs and CsPbI3 PQDs show a facile deposition for light‐emitting diode (LED) application, showing white electroluminescence, indicating that both kinds of QDs are stable during LED operation. Last but not least, the photoluminescence quantum yield of the colloidal mixtures is higher (up to 75%) than single white emitters, showing itself as a promising system for white emission with tunable properties.