Highly Stable Silica-Wrapped Mn-Doped CsPbCl₃ Quantum Dots for Bright White Light-Emitting Devices

Abstract

As an outstanding less-Pb candidate, doping Mn²⁺ ions into perovskite quantum dots (QDs) has received significant interest in the application of light-emitting diodes (LEDs). However, their further applications are impeded by poor chemical instability. Here, the silica-wrapped Mn-doped CsPbCl₃ QDs are fabricated via hydrolyzing (3-aminopropyl) triethoxysilane with improved operational stability. Also, the photoluminescence quantum yield as high as 55.4% for the CsPbMnCl₃@SiO₂ composite is achieved. Silica wrapping can protect the perovskite QDs from damage by temperature and humidity as well as anion exchange. Furthermore, white LED devices are prepared by employing the mixture of green CsPbBr₃ QDs and orange-red CsPbMnCl₃@SiO₂ composites. The as-obtained white LED device operated at a forward current of 20 mA exhibits bright natural light with a high luminous efficiency of 77.59 lm/W, and the corresponding color rendering index of 82 and color temperature (CCT) of 3950 K are obtained. Additionally, the electroluminescence spectrum shows nearly no variation after 24 h operation. This work will promote the Mn-doped CsPbCl₃ QDs material to the practical application in solid-state LEDs.