Improved photoluminescence quantum yield of CsPbBr3 quantum dots glass ceramics

We have fabricated CsPbBr3 perovskite quantum dots (QDs) in a multi-component borate glass by melt-quenching technique. Transmission electron microscopy (TEM) reveals a cubic phase CsPbBr3 crystal for QDs. As the treatment temperature or the treatment time duration increases, the photoluminescence (PL) peak shifts to long wavelength in the range of 510 to 525 nm, and the full width at half-maximum varies in the range of 24 to 18 nm. The absorption edge shifts to low energy side in the range of 2.54 to 2.41 eV. The different photoluminescence excitation spectra (PLE) reflect the change of microstructure for different samples. The PL peak wavelength and line-shape are independent of excitation wavelength. These results of spectra show typical exciton emission characteristics. As treatment conditions strengthens, photoluminescence quantum yield (PLQY) first increases and then decreases, having the best PLQY 86.9%. Bi-exponential fitting curves show that short lifetime tau(1) continuously decreases. Long lifetime tau(2), weight for long lifetime component, and average lifetime tau(avg) first increase and then decrease. The PLQY values are affected by both tau(1) and tau(2), which are relative to the crystal quality in the interior and the surface of QDs, respectively. The high PLQY value corresponds to medium treatment condition, which is attributed to a balanced effect of crystal quality in interior and the surface of QDs.