Ruthenium-Doped InP Quantum Dots for Efficient Red Emission

The synthesis of various transition-metal-doped InP quantumdots(QDs), such as copper, manganese, and silver, for enhanced optoelectronicproperties has been reported to date. Herein, we introduce ruthenium(Ru) doping into InP QDs. After Ru doping, InP QDs showed a significantred shift up to 325 meV due to the introduction of mid-gap states.The optimization studies of the ZnS shell formation on Ru-doped InPcore QDs led to a high photoluminescence quantum yield (PLQY) of 77.6%in the red spectral region, while without ruthenium doping the PLQYreached a maximum level around 60% via the same synthetic approach.Elemental mapping, mass spectrometry, and lattice change confirmedthe incorporation of Ru inside the InP QDs. Moreover, the integrationof Ru-doped QDs into LEDs in a liquid matrix led to an external quantumefficiency of 7.9%. This study demonstrates that Ru doping can bean alternative strategy for efficient red emitters.