Exciton photoluminescence of CsPbBr<sub>3</sub>@SiO<sub>2</sub> quantum dots and its application as a phosphor material in light-emitting devices
Canran Zhang, Hongxiang Zhang, Ru Wang, Daotong You, Wei Wang, Chunxiang Xu, Jun Dai
Abstract
In this report, we mainly investigate the optical property differences between CsPbBr 3 @SiO 2 quantum dots (QDs) and CsPbBr 3 QDs. The photoluminescence demonstrates that CsPbBr 3 @SiO 2 QDs and CsPbBr 3 QDs have similar exciton binding energy. Both CsPbBr 3 and CsPbBr 3 @SiO 2 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 CsPbBr 3 and CsPbBr 3 @SiO 2 QDs have the similar bandgap thermal expansion coefficient, but the CsPbBr 3 @SiO 2 QDs have weaker electron-phonon interaction. Temperature-dependent time-resolved photoluminescence (TRPL) demonstrates that the PL lifetime increases with the temperature and CsPbBr 3 @SiO 2 QDs have longer PL lifetime than CsPbBr 3 QDs after 110 K. In addition, the CsPbBr 3 @SiO 2 QDs integrated on the blue light-emitting diode chip as green phosphor material show better thermal stability in ambient air.