A chemical co-precipitation strategy was employed to synthesize a series of(Gd_(0.95−x)Lu_(x)Eu_(0.05))_(3)Al_(5)O_(12)(x=0.1−0.95)powder phosphors,followed by vacuum sintering to achieve transparent garnet ceramic ph...A chemical co-precipitation strategy was employed to synthesize a series of(Gd_(0.95−x)Lu_(x)Eu_(0.05))_(3)Al_(5)O_(12)(x=0.1−0.95)powder phosphors,followed by vacuum sintering to achieve transparent garnet ceramic phosphors.The density functional theory indicated Lu_(3)Al_(5)O_(12) was formed in priority compared with Gd_(3)Al_(5)O_(12) during solid-phase reaction.Upon high-temperature sintering,the Lu^(3+)substitution for Gd^(3+)suppressed point mass diffusion leading to a smaller grain size.The in-line transmittances of bulk specimens with x=0.1,0.3,0.5,0.7,and 0.95 nm were~83.5%,80.1%,68.8%,73.7%,and 82.2%at 710 nm(Eu^(3+)emission center),respectively,among which the sample of x=0.1 exhibited the optical grade with near-zero optical loss in agreement with the defect-free single crystal(~100%of the theoretical transmittance).The resulting particle and ceramic materials both presented characteristic Eu^(3+)emission arising from 5D0→7FJ(J=1−4)transition,where the dominant far-red emission at~710 nm arising from ^(5)D_(0)→^(7)F_(4) transition overlapped with the absorption of phytochrome(PFR).The photoluminescence excitation and photoluminescence intensities of(Gd_(0.95−x)Lu_(x)Eu_(0.05))_(3)Al_(5)O_(12) powders and ceramics generally increased at a higher Gd^(3+)/Lu^(3+)ratio.Lu^(3+)dopants delayed the fluorescence lifetime while the bulk samples had shorter lifetime compared to the particle counterparts.The transparent(Gd_(0.85)Lu_(0.1)Eu_(0.05))3Al_(5)O_(12) ceramic phosphor exhibited good thermal stability with a high thermal quenching temperature above 533 K.The designed ceramic phosphor-converted light-emitting diode had a saturation injection current of 435 mA and a current-dependent color rendering index.More importantly,our report marked the developmental stage of transparent ceramic materials towards zero optical loss.展开更多
基金supported by Zhejiang Provincial Natural Science Foundation of China(Grant No.LY23F050007).
文摘A chemical co-precipitation strategy was employed to synthesize a series of(Gd_(0.95−x)Lu_(x)Eu_(0.05))_(3)Al_(5)O_(12)(x=0.1−0.95)powder phosphors,followed by vacuum sintering to achieve transparent garnet ceramic phosphors.The density functional theory indicated Lu_(3)Al_(5)O_(12) was formed in priority compared with Gd_(3)Al_(5)O_(12) during solid-phase reaction.Upon high-temperature sintering,the Lu^(3+)substitution for Gd^(3+)suppressed point mass diffusion leading to a smaller grain size.The in-line transmittances of bulk specimens with x=0.1,0.3,0.5,0.7,and 0.95 nm were~83.5%,80.1%,68.8%,73.7%,and 82.2%at 710 nm(Eu^(3+)emission center),respectively,among which the sample of x=0.1 exhibited the optical grade with near-zero optical loss in agreement with the defect-free single crystal(~100%of the theoretical transmittance).The resulting particle and ceramic materials both presented characteristic Eu^(3+)emission arising from 5D0→7FJ(J=1−4)transition,where the dominant far-red emission at~710 nm arising from ^(5)D_(0)→^(7)F_(4) transition overlapped with the absorption of phytochrome(PFR).The photoluminescence excitation and photoluminescence intensities of(Gd_(0.95−x)Lu_(x)Eu_(0.05))_(3)Al_(5)O_(12) powders and ceramics generally increased at a higher Gd^(3+)/Lu^(3+)ratio.Lu^(3+)dopants delayed the fluorescence lifetime while the bulk samples had shorter lifetime compared to the particle counterparts.The transparent(Gd_(0.85)Lu_(0.1)Eu_(0.05))3Al_(5)O_(12) ceramic phosphor exhibited good thermal stability with a high thermal quenching temperature above 533 K.The designed ceramic phosphor-converted light-emitting diode had a saturation injection current of 435 mA and a current-dependent color rendering index.More importantly,our report marked the developmental stage of transparent ceramic materials towards zero optical loss.
