Downconversion （DC） with emission of two near-infrared photons about 1000 nm for each blue photon absorbed was obtained in thulium （Tm3＋） and ytterbium （Yb3＋） codoped yt- trium lithium fluoride （LiYF4） singl...Downconversion （DC） with emission of two near-infrared photons about 1000 nm for each blue photon absorbed was obtained in thulium （Tm3＋） and ytterbium （Yb3＋） codoped yt- trium lithium fluoride （LiYF4） single crystals grown by an improved Bridgman method. The luminescent properties of the crystals were measured through photoluminescence excitation, emission spectra and decay curves. Luminescence between 960 and 1050 nm from yb3＋： 2Fs/2--＋2FT/2 transition, which was originated from the DC from Tm3＋ ions to Yb3＋ ions, was observed under the excitation of blue photon at 465 nm. Moreover, the energy transfer processes were studied based on the Inokuti-Hirayama model, and the results indicated that the energy transfer from Tm3＋ to Yb3＋ was an electric dipole-dipole interaction. The max- imum quantum cutting efficiency approached with 0.49mo1% Tm3＋ and 5.99mo1% Yb3＋. increasing the energy efficiency of crystalline energy part of the solar spectrum. up to 167.5% in LiYF4 single crystal codoped Application of this crystal has prospects for Si solar cells by photon doubling of the high展开更多
Tb^（3＋） and Yb^（3＋） codoped LuPO_4 phosphors were prepared by the reverse-strike co-precipitation method.The obtained LuPO_4：Tb^（3＋）,Yb^（3＋） phosphors were characterized by X-ray diffraction（XRD）,photol...Tb^（3＋） and Yb^（3＋） codoped LuPO_4 phosphors were prepared by the reverse-strike co-precipitation method.The obtained LuPO_4：Tb^（3＋）,Yb^（3＋） phosphors were characterized by X-ray diffraction（XRD）,photoluminescence（PL） spectra and decay kinetics to understand the near-infrared quantum cutting（QC） phenomena.The XRD results showed that all the phosphors exhibited good crystallinity and had a pure tetragonal phase of LuPO_4.The experimental results showed that the strong green emission around 545 nm from Tb^（3＋）（~5D_4→~7F_5） and near-infrared（NIR） emission at 1003 nm from Yb^（3＋）（~2F_（5/2）→~2F_（7/2）） of LuPO_4：Tb^（3＋）,Yb^（3＋）phosphors were observed under 489 nm excitation,respectively.The Yb^（3＋） concentration dependence on luminescent properties and lifetimes of both the visible and NIR emissions were also investigated.The quenching concentration of Yb^（3＋） ions approached as high as 10 mol.%.The excellent luminescence properties of the LuPO_4：Tb^（3＋）,Yb^（3＋） indicated its potential application in improving the energy conversion efficiency of the silicon based solar cells by converting one blue photon to two NIR ones.展开更多
文摘Downconversion （DC） with emission of two near-infrared photons about 1000 nm for each blue photon absorbed was obtained in thulium （Tm3＋） and ytterbium （Yb3＋） codoped yt- trium lithium fluoride （LiYF4） single crystals grown by an improved Bridgman method. The luminescent properties of the crystals were measured through photoluminescence excitation, emission spectra and decay curves. Luminescence between 960 and 1050 nm from yb3＋： 2Fs/2--＋2FT/2 transition, which was originated from the DC from Tm3＋ ions to Yb3＋ ions, was observed under the excitation of blue photon at 465 nm. Moreover, the energy transfer processes were studied based on the Inokuti-Hirayama model, and the results indicated that the energy transfer from Tm3＋ to Yb3＋ was an electric dipole-dipole interaction. The max- imum quantum cutting efficiency approached with 0.49mo1% Tm3＋ and 5.99mo1% Yb3＋. increasing the energy efficiency of crystalline energy part of the solar spectrum. up to 167.5% in LiYF4 single crystal codoped Application of this crystal has prospects for Si solar cells by photon doubling of the high
基金National Science Foundation of China(11004021,10804015)Fundamental Research Funds for the Central Universities(DC10040122,DC10020121)+1 种基金China Postdoctoral Science Foundation(2011M500623)Scientific and Technology Foundation of Dalian(2011J21DW021)
基金supported by the National Natural Science Foundation of China(11404047,11674044,11604037)Chongqing Research Program of Basic Research and Frontier Technology(CSTC2016JCYJA0113,CSTC2016JCYJA0207,CSTC2015JCYJA50005)Research Training Program for Undergraduates of Chongqing University of Posts and Telecommunications(A2015-86,A2016-53)
文摘Tb^（3＋） and Yb^（3＋） codoped LuPO_4 phosphors were prepared by the reverse-strike co-precipitation method.The obtained LuPO_4：Tb^（3＋）,Yb^（3＋） phosphors were characterized by X-ray diffraction（XRD）,photoluminescence（PL） spectra and decay kinetics to understand the near-infrared quantum cutting（QC） phenomena.The XRD results showed that all the phosphors exhibited good crystallinity and had a pure tetragonal phase of LuPO_4.The experimental results showed that the strong green emission around 545 nm from Tb^（3＋）（~5D_4→~7F_5） and near-infrared（NIR） emission at 1003 nm from Yb^（3＋）（~2F_（5/2）→~2F_（7/2）） of LuPO_4：Tb^（3＋）,Yb^（3＋）phosphors were observed under 489 nm excitation,respectively.The Yb^（3＋） concentration dependence on luminescent properties and lifetimes of both the visible and NIR emissions were also investigated.The quenching concentration of Yb^（3＋） ions approached as high as 10 mol.%.The excellent luminescence properties of the LuPO_4：Tb^（3＋）,Yb^（3＋） indicated its potential application in improving the energy conversion efficiency of the silicon based solar cells by converting one blue photon to two NIR ones.
