Overcoming Challenges in InP-Based Quantum Dots: From Nucleation Mechanisms to High-Performance Quantum Dot Light-Emitting Diodes
Indium phosphide-based quantum dots (InP QDs) are positioned as the leading cadmium-free alternative for next-generation display and optoelectronic technologies, offering high photoluminescence quantum yield (PL QY), narrow emission spectra, and size-tunable wavelengths. Commercial deployment, however, remains constrained by synthetic and processing bottlenecks. State-of-the-art InP QD systems typically deliver PL QY below 90% and emission linewidths exceeding 35 nm, while device external quantum efficiency (EQE) and operational lifetime improve only incrementally. This review systematically examines the nucleation mechanisms governing InP core formation and evaluates optimization strategies for core/shell heterostructures, ligand engineering, and device architecture. A comprehensive analysis of recent breakthroughs in red, green, and blue InP-based quantum dot light-emitting diodes (QLEDs) is presented, with emphasis on charge transport modulation and suppression of charge leakage. Despite progress, a significant performance gap persists for practical display applications. Critical unresolved challenges include achieving high-performance electroluminescence from small QDs, mitigating imbalanced carrier injection that drives Auger recombination, Joule heating, and low recombination efficiency, elucidating luminescence and aging mechanisms, and improving blue-emitting device performance. The review concludes by outlining pathways to overcome these limitations, including fabrication of large-sized InP QDs with near-unity PL QY, enhancement of radiative recombination and light extraction efficiency, advanced characterization of degradation mechanisms, and performance enhancement of blue InP-based QLEDs.