Luminescent properties of Bi-doped polycrystalline KAlCl4
  We observed an intensive near-infrared luminescence in Bi-doped KAlCl4 polycrystalline material. Luminescence dependence on the excitation wavelength and temperature of the sample was studied. Our experimental results allow asserting that the luminescence peaked near 1 um belongs solely to Bi+ ion which isomorphically substitutes potassium in the crystal. It was also demonstrated that Bi+ luminescence features strongly depend on the local ion surroundings. 
A. A. Veber, A. N. Romanov, O. V. Usovich, Z. T. Fattakhova, E. V.   Haula, V. N. Korchak, L. A. Trusov, P. E. Kazin, V. B. ...
physics.optics cond-mat.mtrl-sci cond-mat.other