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

Rapid synthesis of AgInS2 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 degrees C to prepare AIS QDs with high luminescence properties. Meanwhile, 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) 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 degrees 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)Si2O2N2:Eu2+ 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. (c) 2022 Elsevier B.V. All rights reserved.