MXene Quantum Dots for White Light-Emitting Diodes: From Controlled Synthesis and Surface Chemistry to Device Architectures and Industrial Prospects

MXene quantum dots (MQDs) have recently emerged as zero-dimensional nanomaterials for white light-emitting diodes (WLEDs) owing to their ultrasmall size, high ratio, and tunable surface terminations. These attributes induce broadband, surface-state-dominated photoluminescence (PL) distinct from conventional semiconductor quantum dots and rare-earth phosphors, enabling simplified device architectures and excitation-flexible white emission. This article reviews MQDs for WLED applications along the materials-to-device pathway, analyzing state-of-the-art top-down and bottom-up synthesis strategies with particular emphasis on size control, crystallinity, scalability, and process integration. Surface chemistry and defect engineering are discussed as parameters governing structural stability, dispersibility, and interfacial compatibility. The optical and PL properties of MQDs are examined from a mechanistic perspective, highlighting quantum confinement effects, surface-state-mediated emission, excitation-dependent and excitation-independent behavior, and quantum yield enhancement strategies. Representative MQD-based WLED architectures and polymer–MQD hybrids are reviewed. Scientific challenges and industrial prospects for scalable manufacturing and device integration are outlined.