The Rise of InP Quantum Dots in Nanoscience

The once-undisputed dominance of heavy metal (e.g., cadmium and lead)-based quantum dots (QDs), driven by their excellent optical and functional characteristics, is now challenged by environmental concerns over metal ion leaching due to their high degree of ionicity and associated toxicity. These issues have prompted a search for eco-friendly semiconductor QDs. Among them, indium phosphide (InP) QDs─a III–V semiconductor system─have emerged as a promising candidate with robust structural properties. However, the development of InP QDs has been impeded by several inherent challenges, including a high degree of covalency and the need for highly reactive precursors in synthesis. Recent efforts, driven by improved synthetic methodologies, have effectively suppressed trap state processes in InP QDs through the development of sophisticated core/shell and alloyed structures. Attempts to understand the photophysics of InP-based QDs through various time-resolved investigations at the ensemble and single-particle levels and their technological prospects are summarized.