Tunable spectrum aqueous Ag-In-Zn-Ga-S quantum dots with high photoluminescence quantum yield

In recent years, Ag-In-Ga-S (AIGS) quantum dots (QDs) have received widespread attention as non-toxic and environmentally friendly QDs. However, the low photoluminescence quantum yield (PLQY) restricts the further application of AIGS QDs in optoelectronic devices. Here, we constructed quinary Ag-In-Zn-Ga-S (AIZGS) QDs with outstandingly high PLQY of 92.1% by doping Zn into AIGS QDs via an economical and environment-friendly hydrothermal method. The synergistic action of the internal doped Zn providing radiative recombination channels and the surface doped Zn passivating the non-radiative recombination defects leads to enhanced PLQY of QDs. The corresponding QDs backlight films fabricated based on AIZGS QDs and polyvinyl alcohol (PVA) also show a high PLQY of 82.7%. The improved PLQY of AIZGS QDs is comparable to other toxic metal-containing QDs in the same spectrum. Furthermore, the PL peak wavelength of the QDs can be tuned from 545 nm to 616 nm by varying the Ag/In ratio. The realization of high PLQY in aqueous AIZGS QDs and its backlight films contributes to the application in the field of eco-friendly backlight display devices.