The poor moisture resistance of Mn^(4+)-activated fluoride red phosphors restricts their practical applications.Herein,this work proposes the embedment of small radius cations(Si^(4+)or Ge^(4+))into the inert shell(K_...The poor moisture resistance of Mn^(4+)-activated fluoride red phosphors restricts their practical applications.Herein,this work proposes the embedment of small radius cations(Si^(4+)or Ge^(4+))into the inert shell(K_(2)TiF_(6))constructed on the surface of K_(2)TiF_(6):Mn^(4+)particles,which increases the covalence of the surface lattice and thus leads to a significant improvement of the stability of the fluoride.By using multidimensional microstructural characterization techniques,we confirmed the construction of a heterogeneous shell(K_(2)Ti_(1−x)Si_(x)F_(6) and K_(2)Ti_(1−y)Ge_(y)F_(6))and systematically investigated the construction process.Compared to the untreated K_(2)TiF_(6):Mn^(4+),the external quantum efficiencies of the K_(2)TiF_(6):Mn^(4+)@K_(2)Ti_(1−x)Si_(x)F_(6) and K_(2)TiF_(6):Mn^(4+)@K_(2)Ti_(1−y)Ge_(y)F_(6) heterogeneous core–shell particles improved by 2–3%,and 99%and 88%of the initial luminescence intensity were maintained after boiling in water for 50 min,respectively,which are significantly better than that(25%)of the homogeneous K_(2)TiF_(6):Mn^(4+)@K_(2)TiF_(6).The aging of red and white light-emitting diode devices at a high temperature(85℃)and a high humidity(85%)shows that the heterogeneous core–shell structures have higher stability than their homogeneous counterparts.The surface lattice enhancement strategy proposed in this work is useful as a reference for improving the properties of other under-stable materials.展开更多
基金supported by the National Natural Science Foundation of China(No.21501058)the Changsha Natural Science Foundation(No.kq2202235).
文摘The poor moisture resistance of Mn^(4+)-activated fluoride red phosphors restricts their practical applications.Herein,this work proposes the embedment of small radius cations(Si^(4+)or Ge^(4+))into the inert shell(K_(2)TiF_(6))constructed on the surface of K_(2)TiF_(6):Mn^(4+)particles,which increases the covalence of the surface lattice and thus leads to a significant improvement of the stability of the fluoride.By using multidimensional microstructural characterization techniques,we confirmed the construction of a heterogeneous shell(K_(2)Ti_(1−x)Si_(x)F_(6) and K_(2)Ti_(1−y)Ge_(y)F_(6))and systematically investigated the construction process.Compared to the untreated K_(2)TiF_(6):Mn^(4+),the external quantum efficiencies of the K_(2)TiF_(6):Mn^(4+)@K_(2)Ti_(1−x)Si_(x)F_(6) and K_(2)TiF_(6):Mn^(4+)@K_(2)Ti_(1−y)Ge_(y)F_(6) heterogeneous core–shell particles improved by 2–3%,and 99%and 88%of the initial luminescence intensity were maintained after boiling in water for 50 min,respectively,which are significantly better than that(25%)of the homogeneous K_(2)TiF_(6):Mn^(4+)@K_(2)TiF_(6).The aging of red and white light-emitting diode devices at a high temperature(85℃)and a high humidity(85%)shows that the heterogeneous core–shell structures have higher stability than their homogeneous counterparts.The surface lattice enhancement strategy proposed in this work is useful as a reference for improving the properties of other under-stable materials.
