Luminescence of CdCl₂-CdBr₂Solid Solutions

Abstract

Studies of optical absorption and luminescence were carried out on CdCl 2 -CdBr 2 solid solutions in the whole concentration range. Three emission bands were observed in the regions of 2.1∼2.3 eV (Y-emission), of 2.4∼2.7 eV (G-emission) and of 3.2∼3.6 eV (UV-emission). When the concentration of CdBr 2 increases, the UV- and the Y-emission bands increase their intensities and shift toward the low energy side to reach final locations of intrinsic emission bands at 3.30 and 2.15 eV of CdBr 2 , respectively, whereas the G-emission band, which is associated with the isolated Br - -ions in the CdCl 2 -lattice in the case of very low concentration, diminishes its intensity gradually. It is proposed that the initial states of these luminescence are the relaxed excitonic states of [Cd 2+ X - 6 ] 4- -complex molecular ions, where X - is Br - or Cl - . The concentration and the temperature dependence of these luminescence are discussed with this model.