Influence of F/Cl Ratio on the Crystal Growth and Luminescence Properties of PbFCl Crystals

Lead fluoride chloride (PbFCl) crystal has been proposed for dual readout application as it has excellent properties. In this study, the PbFCl crystals were grown with different F/Cl ratios in the raw materials by modified Bridgman method. It is observed that excessive PbCl2 in the raw materials is helpful to grow transparent crystals, meanwhile it may enhance the cleavage. The excessive PbF2 or PbCl2 only modifies the cell parameters, not the phase of PbFCl crystal. The emission peaks in X-ray excited luminescence spectra do not depend on the F/Cl ratio in the raw materials. The UV cut-off edge of transmittance shifts from 300 nm to 275 nm when extra PbCl2 was added. According to the emission weighted transmittance of the samples, the crystals grown with F/Cl=1:1.25 in the raw materials show the best dual readout properties among all the samples.