Exciton photoluminescence of CsPbBr3@SiO2 quantum dots and its application as a phosphor material in light-emitting devices

Abstract

In this report, we mainly investigate the optical property differences between CsPbBr3@SiO2 quantum dots (QDs) and CsPbBr3 QDs. The photoluminescence demonstrates that CsPbBr3@SiO2 QDs and CsPbBr3 QDs have similar exciton binding energy. Both CsPbBr3 and CsPbBr3@SiO2 QDs present optical bandgaps and photoluminescence (PL) linewidth broadening as the temperature increases from 10 K to room temperature, which is attributed to the thermal expansion and electron-phonon coupling. The fitting results show that CsPbBr3 and CsPbBr3@SiO2 QDs have the similar bandgap thermal expansion coefficient, but the CsPbBr3@SiO2 QDs have weaker electron-phonon interaction. Temperature-dependent time-resolved photoluminescence (TRPL) demonstrates that the PL lifetime increases with the temperature and CsPbBr3@SiO2 QDs have longer PL lifetime than CsPbBr3 QDs after 110 K. In addition, the CsPbBr3@SiO2 QDs integrated on the blue light-emitting diode chip as green phosphor material show better thermal stability in ambient air.