Liquid Scintillators Loaded with up to 40 Weight Percent Cesium Lead Bromide Quantum Dots for Gamma Scintillation
Hao Yu, Tianheng Chen, Ziqing Han, Jiacheng Fan, Qibing Pei
Abstract
Cesium lead bromide quantum dot (CsPbBr3 QD) is emerging as a promising luminescent material for gamma ray detection. However, its intensive self-absorption traps the luminescent photons generated and diminishes the scintillation light yield. The self-absorption is magnified at high CsPbBr3 QD loading and large scintillator volume, which are required to effectively attenuate gamma photons. We report a liquid scintillator loaded with up to 40 wt % of CsPbBr3 QDs. Pyrromethene 580 (PM-580), a fluorescent dye, was co-dissolved in the solution as a fluorescence resonance energy-transfer acceptor to overcome the self-absorption of the QDs. The rapid energy transfer from the QDs to PM-580 also accelerates the scintillation decay kinetics. The scintillation light yield of the liquid containing 20 wt % QDs and 0.75 wt % PM-580 was 8800 photons/MeV. The decay lifetime is 24.3 ns, faster than most inorganic crystal scintillators. The light yield was 7300 photons/MeV at 40 wt % QD loading. Gamma pulse spectroscopy of the 40 wt % QD liquid produced the 662 keV gamma photopeak with a 27% energy resolution, demonstrating the potential of the CsPbBr3 QD loaded organic scintillators for spectroscopic gamma detection.