Modification of CaS:Eu phosphor under mild conditions toward an extreme stability at harsh environment over 1.5 months

The chemical instability of CaS:Eu phosphors is a curial problem that hinders its practical application, especially under high temperature and humid environment. In this work, CaS:Eu capped by methacrylate-functionalized Si compound are successfully prepared under a mild condition, without seriously sacrificing the photoluminescence capability. The stability of the as-prepared samples is subsequently tested in stirred hot water (90 °C) for over a month, the outstanding hydrophobicity and chemical stability of the as-prepared samples sufficiently reserve the optical and chemical properties. Systematic characterizations are conducted to reveal the chemical features of the modified CaS:Eu phosphor.