The multilayered structure thin films(Gd_(2)(MoO_(4))_(3):Ho(Tm)/Yb@Gd_(2)(MoO_(4))_(3):Yb) were prepared through sol-gel and spin-coating method,while the average thinness was nearly 140 nm.We investigated the up-con...The multilayered structure thin films(Gd_(2)(MoO_(4))_(3):Ho(Tm)/Yb@Gd_(2)(MoO_(4))_(3):Yb) were prepared through sol-gel and spin-coating method,while the average thinness was nearly 140 nm.We investigated the up-conversion luminescence of Gd_(2)(MoO_(4))_(3):Ho(Tm)/Yb@Gd_(2)(MoO_(4))_(3):Yb thin films,The results show that the double-layer structured thin films are able to increase the emission intensity.The fluorescence enhancement factors of the luminescence from Gd_(2)(MoO_(4))_(3):Ho/Yb@Gd_(2)(MoO_(4))_(3):Yb thin films,located at540 and 662 nm,reach 7.5 and 4.3,respectively.And the enhancement factors of emissions located at450,475 and 650 nm(Gd_(2)(MoO_(4))_(3):Tm/Yb@Gd_(2)(MoO_(4))_(3):Yb) reach 9,2 and 2,respectively.The considerable enhancement is due to the suppression of surface quenching and energy harvesting via the Yb ions in the outer shell.In addition,the emission color of thin films can be modulated from yellow to blue via tuning the number of Gd_(2)(MoO_(4))_(3):Ho/Yb and Gd_(2)(MoO_(4))_(3):Tm/Yb layers,which provides a feasible strategy to tune the up-conversion emission color.展开更多
Alternating current electroluminescence(ACEL)shows great potential in lighting,display and intelligent skin.Herein,the ACEL properties of Pr3þ-doped Ba0$85Ca0$15Ti0$90Zr0$10O3 ceramic and its PDMS-based composite...Alternating current electroluminescence(ACEL)shows great potential in lighting,display and intelligent skin.Herein,the ACEL properties of Pr3þ-doped Ba0$85Ca0$15Ti0$90Zr0$10O3 ceramic and its PDMS-based composite have been investigated.Intense red EL emission was obtained in the ceramic sample whereas blue EL emission of Pr3þwas observed for the first time in the composite counterpart.The red EL emission should be attributed to the impact of hot electrons driven by the large piezoelectric electric field.Owing to the cross-relaxations through the 4f5d levels and Pr-to-metal charge transfer state,the 3 PJ emissions were completely quenched,and thus leading to an enhancement in red emission.However,external E field induced a large local piezoelectric deformation of the ceramic particles embedded in the PDMS matrix,which in turn caused a bending of CB and then a downwards shift of the 4f5d levels from the CB.Hence the cross-relaxations were hindered,and the blue EL emission was observed in the composites.The results would attract attention of functional materials studies and expand our understanding of such facile structure and oxide EL devices to facilitate their use in integral part of flexible device systems.展开更多
基金Project supported by the National Natural Science Foundation of China(11474078)。
文摘The multilayered structure thin films(Gd_(2)(MoO_(4))_(3):Ho(Tm)/Yb@Gd_(2)(MoO_(4))_(3):Yb) were prepared through sol-gel and spin-coating method,while the average thinness was nearly 140 nm.We investigated the up-conversion luminescence of Gd_(2)(MoO_(4))_(3):Ho(Tm)/Yb@Gd_(2)(MoO_(4))_(3):Yb thin films,The results show that the double-layer structured thin films are able to increase the emission intensity.The fluorescence enhancement factors of the luminescence from Gd_(2)(MoO_(4))_(3):Ho/Yb@Gd_(2)(MoO_(4))_(3):Yb thin films,located at540 and 662 nm,reach 7.5 and 4.3,respectively.And the enhancement factors of emissions located at450,475 and 650 nm(Gd_(2)(MoO_(4))_(3):Tm/Yb@Gd_(2)(MoO_(4))_(3):Yb) reach 9,2 and 2,respectively.The considerable enhancement is due to the suppression of surface quenching and energy harvesting via the Yb ions in the outer shell.In addition,the emission color of thin films can be modulated from yellow to blue via tuning the number of Gd_(2)(MoO_(4))_(3):Ho/Yb and Gd_(2)(MoO_(4))_(3):Tm/Yb layers,which provides a feasible strategy to tune the up-conversion emission color.
基金funded by Research Grant Council of Hong Kong Special Administrative Region(PolyU 152236/17E)Program for Chang Jiang Scholars and Innovative Research Teams in Universities(No.IRT_17R40)+2 种基金Science and Technology Program of Guangzhou(No.201904020007)China Postdoctoral Science Foundation(2020M672667)funded by Guangdong Provincial Key Laboratory of Optical Information Materials and Technology(2017B030301007).
文摘Alternating current electroluminescence(ACEL)shows great potential in lighting,display and intelligent skin.Herein,the ACEL properties of Pr3þ-doped Ba0$85Ca0$15Ti0$90Zr0$10O3 ceramic and its PDMS-based composite have been investigated.Intense red EL emission was obtained in the ceramic sample whereas blue EL emission of Pr3þwas observed for the first time in the composite counterpart.The red EL emission should be attributed to the impact of hot electrons driven by the large piezoelectric electric field.Owing to the cross-relaxations through the 4f5d levels and Pr-to-metal charge transfer state,the 3 PJ emissions were completely quenched,and thus leading to an enhancement in red emission.However,external E field induced a large local piezoelectric deformation of the ceramic particles embedded in the PDMS matrix,which in turn caused a bending of CB and then a downwards shift of the 4f5d levels from the CB.Hence the cross-relaxations were hindered,and the blue EL emission was observed in the composites.The results would attract attention of functional materials studies and expand our understanding of such facile structure and oxide EL devices to facilitate their use in integral part of flexible device systems.
