Blue and green light exciton emission of chloro-brominated perovskite quantum dots glasses

Blue and green light emitting CsPbBr3 and CsPb(Cl/Br)(3) perovskite quantum dots glasses (QDGs) have been fabricated in multi-component borate glass matrices by melt quenching method and following heat treatment. Absorption spectra show regular blue shift of first exciton absorption peak from CsPbBr3 to CsPb(Cl/Br)(3) QDGs. Photoluminescence spectra show that CsPbBr3 and CsPb(Cl/Br)(3) QDGs have adjustable emission in the wave-lengths from 528 to 442 nm. The full width at half maximum (FWHM) is 15-17 nm and 21-31 nm for CsPbBr3 and CsPb(Cl/Br)(3) QDGs respectively. Emission map and photoluminescence excitation spectra show broad band excitation characteristics of the exciton emission. Photoluminescence decay shows bi-exponential function for both CsPbBr3 and CsPb(Cl/Br)(3) QDGs. As the ratio of Cl/Br increases from CsPbBr3 to CsPb(Cl/Br)(3) QDGs, the short and long lifetime components roughly decrease from 9.7 to 4.0 ns and from 87.8 to 55.2 ns respectively, and the average lifetime decreases from 72.2 to 36.5 ns. Photoluminescence quantum yield changes from 82.8% to 5.7%. Temperature dependence of PL spectra in the range of 28-120 degrees C shows that integrated intensity obviously decreases with increasing temperature, but the emission peak wavelength and FWHM almost do not change.