No abstract

In delafossite-type oxides of CuR x Y 1-x O 2 (R = Eu, Tb or Tm) and CuR x Ca y Y 1-x-y O 2 prepared through the conventional solid state reactions, the lattice constant dependence on the composition implies doping with the Tb 3+ , Eu 3+ and Tm 3+ cations on the Y 3+ site. Noticeable sharp emission lines due to the f -f transitions of Eu 3+ , Tb 3+ and Tm 3+ are observed at room temperature in CuR x Ca y Y 1-x-y O 2 as well as CuR x Y 1-x O 2 . P-type conductivity of CuR x Ca y Y 1-x-y O 2 increases with increasing Ca concentration, indicating the increase of hole concentration caused by doping with Ca 2+ acceptor cation on the Y 3+ site. These results indicate the controllability of the luminescence and conductivity in delafossite-type CuYO 2 oxides by co-doping with Eu, Tb or Tm rare-earth cation and Ca acceptor cation on the Y 3+ sites. 25 262 7261 N. Tsuboi et al.: P-type conductive CuYO 2 phosphor Co-doped with Eu, Tb or Tm rare-earth cation

Delafossite-type CuYO2 and CuY1-x Ca x O2 (x≤0.05) samples exhibited a green-PL-emission band due to the Cu+ interconfiguration transition from 3d94s1 to 3d10 at room temperature. With increasing Ca concentration, the Cu+ emission shifted slightly to the shorter-wavelength side with a slightly weaker emission intensity. This slight change in Cu+ emission property is considered to be caused by the increase in hole concentration within the Cu+ layer arising from the increase in Ca concentration. On the other hand, oxygen-annealed CuYO2 samples exhibited no emissions. The increase in nonradiative relaxation processes in the oxygen-annealed CuYO2 samples is possibly related to structural changes such as orthorhombic distortion during the oxygen annealing. In the photoluminescence of delafossite-type CuY1-y Tb y O2 (y=0.05) at room temperature, no Cu+ emission band was observed, but sharp emission lines were observed. All the emission lines were assigned to the f-f transitions of Tb3+ (5D4→7F J , J=3–6).

No abstract