Origin of bimodal luminescence in Cs4PbBr6 quantum dots glass ceramic

Origin of Radioluminescence in Low-Dimensional Halide Perovskite Glass Ceramics under X-ray Excitation

“…To eliminate the influence of the glass matrix, glass ceramics without QDs were prepared under the same experimental conditions, and then, the glass ceramics were excited by 50 keV X-rays, but the results show that almost no luminescence could be detected in the RL spectrum (Figure a). It can be seen from these results that the wide peak located at 433 nm is still only related to Cs 4 PbBr 6 QDs. , However, when the sample glass was placed in the air environment for 5 days, as shown in Figure b, it could be found that the broad emission peak at 433 nm still existed, while a narrow emission peak at 520 nm appeared, and the characteristics of this 520 nm emission peak were exactly consistent with the RL luminescence of Cs 4 PbBr 6 reported previously. , Significantly, when the Cs 4 PbBr 6 sample continued to be placed in the air for the 10th day, only single peak emission can be observed in the RL spectrum. To further explore the origin of the broad emission peak, the Cs 4 PbBr 6 glass ceramic powder placed for 30 days was characterized by XRD again.…”

“…It can be seen from these results that the wide peak located at 433 nm is still only related to Cs 4 PbBr 6 QDs. 25,26 However, when the sample glass was placed in the air environment for 5 days, as shown in Figure 3b, it could be found that the broad emission peak at 433 nm still existed, while a narrow emission peak at 520 nm appeared, and the characteristics of this 520 nm emission peak were exactly consistent with the RL luminescence of Cs 4 PbBr 6 reported previously. 20,21 Significantly, when the Cs 4 PbBr 6 sample continued to be placed in the air for the 10th day, only single peak emission can be observed in the RL spectrum.…”

“…Therefore, the quantum yield measurement is used to quantify the luminescence efficiency of Cs 4 PbBr 6 QDs, and the experimental results show that the quantum yield can be achieved at 49.7% (Figure 2c), which is greatly higher than our previous reports. 26 The radioluminescence of scintillators is derived from the photoelectric interaction between high-energy X-rays and atoms in materials. As the high PLQY from Cs 4 PbBr 6 QDs is favorable for effective radiative recombination in the scintillation process and the stable crystal structure can effectively extend the service life of the scintillator material, the Cs 4 PbBr 6 crystal has become a significant member of the scintillator family.…”

“…It can be seen from the PL spectra (Figure d) that the Cs 4 PbBr 6 QDs glass ceramic powder shows a bright green luminescence peak at a wavelength of 510 nm under the excitation of 365 nm UV light. Therefore, the quantum yield measurement is used to quantify the luminescence efficiency of Cs 4 PbBr 6 QDs, and the experimental results show that the quantum yield can be achieved at 49.7% (Figure c), which is greatly higher than our previous reports …”

“…For the samples tested continuously on the same day, the longer the X-ray irradiation time, the weaker the luminous intensity. This is because, under the focused irradiation of high-energy X-rays, the temperature of the sample increases and the luminous intensity decreases due to the influence of lattice thermal expansion . Nevertheless, with the progress of the cycle experiment, the luminescence of the sample under X-ray irradiation gradually increased and reached the maximum on the 8th day (Figure a), and the RL intensity of the Cs 4 PbBr 6 glass ceramic was enhanced by 6.2 times.…”