Improving photoluminescence and thermal stability of CaSi2O2N2:Eu2+ phosphors by codoping lanthanide ions (Ln = Sc, La, Gd, Yb, Lu)

In this research, trivalent lanthanide ions Ln(3+) (Ln = Sc, La, Gd, Y, Lu) were codoped into the CaSi2O2N2:Eu2+ matrix for substituting at the Ca2+ sites to improve the photoluminescence and thermal stability. X-ray diffraction, photoluminescence excitation and emission, lifetime decay and thermal quenching behavior were used to characterized the resulting samples. It was observed that the photoluminescence and thermal stability of CaSi2O2N2:Eu2+ phosphors could be obviously enhanced by co-doping Sc3+ and Lu3+ ions, especially an obvious improvement in the addition of Lu3+ ions, but not for Gd3+ and Yb3+ ions. The possible mechanism is the decrease of the nonradiative transition probability of Eu2+ ions as a result of Ln(3+) doping by the modification of crystal lattice and the increase of the solubility of Eu2+ ions. (C) 2017 Elsevier B.V. All rights reserved.