Rapid synthesis of AgInS2 quantum dots by microwave assisted-hydrothermal method and its application in white light emitting diodes

Rapid synthesis of AgInS 2 quantum dots (AIS QDs) with high quantum yield and crystallinity in aqueous phase has been identified as a research priority in the realm of colloidal semiconductors. Herein, microwave assisted-hydrothermal method was used to react for 5 min at 120 °C to prepare AIS QDs with high luminescence properties. Meanwhile, 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF 4 ) ionic liquid (IL) was employed as a wave absorber to enhance the photoluminescence quantum yield (PLQY) and shorten the reaction time. The AIS QDs exhibited spectral tunability by adjusting the IL/AgIn molar ratio from 0 to 10, and the luminescence peak position could be tuned from 597 nm to 670 nm. The PLQY of AIS QDs reached 27.67% at the IL/AgIn molar ratio of 2.5, and the fluorescence lifetime upped to 360.4 ns. In addition, the ZnS shell was coated on the surface of the QDs with Zn/AgIn= 3 by reacting at 90 °C for 2 min, and the PLQY could reach to 35.66%, which further improved the emission performance of the AIS QDs. Finally, QDs and commercial (Ba, Sr)Si 2 O 2 N 2 :Eu 2+ phosphors were mixed to fabricate white light emitting diodes (WLEDs) devices. AIS@ZnS QDs-based WLED showed color rendering index (CRI) of 87.7 and correlated color temperature (CCT) of 5220 K. And its luminous efficiency (LE) reached 80.13 lm/W, which is 2.16 times higher than that of AIS QDs-based WLED (37.1 lm/W), indicating the good application prospect in WLEDs.