Wide-Color-Gamut, Eco-Friendly Full-Color QLED Displays Enabled by SEL-WQLEDs With Interference Color Filters

Quantum dot light-emitting diodes (QLEDs) are widely recognized as a promising next-generation display technology. Yet, they face critical challenges, including the toxicity of cadmium/lead (Cd/Pb)-based heavy metals and the lack of mature, simple, and cost-effective arraying techniques. Herein, we employed heavy-metal-free red/green/blue QDs (R-/G-/B-QDs) as tricolor emissive centers to fabricate single-emissive-layer white QLEDs (SEL-WQLEDs). By regulating charge distribution and Förster resonant energy transfer (FRET) in the R-/G-/B-QD mixed emissive layer (EML), the electroluminescence (EL) performance and spectrum of SEL-WQLEDs were simultaneously improved. The optimal device exhibited a peak external quantum efficiency (EQE) of 4.9% and emitted relatively balanced R/G/B light. Furthermore, we proposed a full-color display technical route in which interference color filters (ICFs) were transferred onto SEL-WQLED pixels. Benefitting from the narrow bandpass and high transmittance characteristics of the ICFs, the resulting QLED display achieved an exceptional color gamut of 113% NTSC (National Television System Committee) and excellent viewing-angle spectral stability over a range of 0°-30°, meeting the application requirements of near-eye displays, i.e., virtual reality/augmented reality (AR/VR). Based on the technical route, we designed a Google Glass-inspired prototype and successfully demonstrated its display functionality. This work offers a promising eco-friendly technical route for developing full-color QLED displays.