Indium phosphide (InP) QDs have emerged as promising eco-friendly alternatives to toxic Cd-containing QDs, with excellent optical properties for lighting and display applications. However, the development of blue-emitting InP QDs has been hindered by surface defects of small-sized cores and lattice mismatch between core and shell. Meanwhile, traditional dilute magnetic semiconductors (DMSs) suffer from insufficient Curie temperature, failing to meet the practical demands of spintronics.
Herein, the research team reports Cr 3+ -doped InP/ZnS QDs with dual functionalities via a hot injection method. By using Cr(acac) 3 as the chromium source, combined with ligand engineering and core-shell interface design, Cr³⁺ ions are precisely embedded into the core-shell interface of QDs. This strategy effectively passivates the surface defects of InP cores and suppresses non-radiative recombination, resulting in pure blue-emitting QDs with an emission wavelength of 471 nm, a photoluminescence quantum yield (PLQY) of 52%, and a full width at half maximum (FWHM) of 46 nm. More importantly, Cr 3+ ions form a Cr-P-Cr coordination bridge structure on the InP core surface. Dominated by ferromagnetic superexchange interaction, synergized with the intrinsic strong local magnetic moment of Cr 3+ and quantum confinement effect, room-temperature ferromagnetism is achieved in InP-based QDs for the first time—with a Curie temperature exceeding 350 K, a maximum coercivity of 95.45 Oe. This solves the critical issue of low magnetic ordering temperature in traditional DMSs.
This work provides new materials for spintronic devices, and the Cr 3+ doping strategy also offers a reference for the opto-magnetic regulation of III-V QDs. The work entitled “ Dual-functional Cr 3+ -doped InP quantum dots with pure blue emission and room-temperature ferromagnetism ” was published in Advanced Powder Materials (Available online on 8 January 2026).
Advanced Powder Materials
Experimental study
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Dual-functional Cr3+-doped InP quantum dots with pure blue emission and room-temperature ferromagnetism
8-Jan-2026