ZnGa_(2)O_(4):Cr^(3+)persistent luminescent phosphors(PLPs)have been widely applied in bioimaging and photonics due to their ultra-long near-infrared(NIR)afterglow.However,UV and visible excitation currently in use ha...ZnGa_(2)O_(4):Cr^(3+)persistent luminescent phosphors(PLPs)have been widely applied in bioimaging and photonics due to their ultra-long near-infrared(NIR)afterglow.However,UV and visible excitation currently in use have shallow penetration depths or harmful effects on organisms,which limit long-term bioimaging.Therefore,developing NIR PLPs excited by NIR light is urgent for bioimaging.Here,Zn_(1-x)(Li/Ga)_(x)Ga_(2)O_(4):Cr^(3+)(x=0-1)NIR PLPs were synthesized.All the newly introduced Ga^(3+)ions occupy the tetrahedral sites.However,with increasing Li^(+)/Ga^(3+)content,Li^(+)ions first occupy the tetrahedral position,then partially enter octahedral sites,and completely occupy the octahedral sites at x=1.The incorporation of Li^(+)/Ga^(3+)contributes to weakened crystal field strength,which leads to a deeper trap depth and a wider trap energy level.Complete replacement of Zn^(2+)with Li^(+)/Ga^(3+)ions leads to the splitting of the trap energy level into two-divided ones,which reduces the electron transfer between deep/shallow traps and makes the deep trap energy level come close to the 2E energy level of Cr^(3+).Therefore,an enhanced NIR afterglow excited by the low-energy NIR light is found for the Li^(+)/Ga^(3+)doped sample.This work provides a new category for NIR-absorptive-NIR-emissive PLPs and proposes a new phosphor for long-term bioimaging.展开更多
基金supported in part by the Natural Science Foundation of Liaoning Province(Grant 2020-MS-081)the National Natural Science Foundation of China(Grants 51302032,U21A2045,and 52172112).
文摘ZnGa_(2)O_(4):Cr^(3+)persistent luminescent phosphors(PLPs)have been widely applied in bioimaging and photonics due to their ultra-long near-infrared(NIR)afterglow.However,UV and visible excitation currently in use have shallow penetration depths or harmful effects on organisms,which limit long-term bioimaging.Therefore,developing NIR PLPs excited by NIR light is urgent for bioimaging.Here,Zn_(1-x)(Li/Ga)_(x)Ga_(2)O_(4):Cr^(3+)(x=0-1)NIR PLPs were synthesized.All the newly introduced Ga^(3+)ions occupy the tetrahedral sites.However,with increasing Li^(+)/Ga^(3+)content,Li^(+)ions first occupy the tetrahedral position,then partially enter octahedral sites,and completely occupy the octahedral sites at x=1.The incorporation of Li^(+)/Ga^(3+)contributes to weakened crystal field strength,which leads to a deeper trap depth and a wider trap energy level.Complete replacement of Zn^(2+)with Li^(+)/Ga^(3+)ions leads to the splitting of the trap energy level into two-divided ones,which reduces the electron transfer between deep/shallow traps and makes the deep trap energy level come close to the 2E energy level of Cr^(3+).Therefore,an enhanced NIR afterglow excited by the low-energy NIR light is found for the Li^(+)/Ga^(3+)doped sample.This work provides a new category for NIR-absorptive-NIR-emissive PLPs and proposes a new phosphor for long-term bioimaging.
