Photoluminescence of PbBr2, PbCl2 and β-PbF2 single crystals

Photoluminescence measurements on a PbBr2 single crystal at 4.2 K revealed a violet and a yellow emission band, in addition to the UV, blue and red band which were already known. The violet and blue luminescence are ascribed to emission of an exciton bound by a defect. The UV emission is quenched at much lower temperature than reported previously, because of a more effective energy transfer from the exciton to defect centres. Luminescence results on PbCl2 and β-PbF2 are in fair agreement with those of other authors.