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
采用水热法制备了Yb^(3+)/Tm^(3+)共掺Y2(Mo O _4)_3系列上转换发光粉。由于Tm^(3+)在980nm附近没有吸收,单掺Tm^(3+)的样品观测不到任何发射。引入Yb^(3+)后,借助Yb^(3+)对980nm红外光的吸收和Yb^(3+)到Tm^(3+)的能量传递,在可将光区...采用水热法制备了Yb^(3+)/Tm^(3+)共掺Y2(Mo O _4)_3系列上转换发光粉。由于Tm^(3+)在980nm附近没有吸收,单掺Tm^(3+)的样品观测不到任何发射。引入Yb^(3+)后,借助Yb^(3+)对980nm红外光的吸收和Yb^(3+)到Tm^(3+)的能量传递,在可将光区观察到源自Tm^(3+)的蓝光和红光。这两个波段的发射随着Yb^(3+)和Tm^(3+)的浓度增加均呈现先增强后减弱的变化规律,8%和0.5%对应Yb^(3+)和Tm^(3+)的最佳掺杂浓度。上转换发射的功率关系研究表明,蓝、红光均为三光子过程,因此二者的产生过程为连续三步Yb^(3+)到Tm^(3+)的能量传递。展开更多
This research investigated the effect of different contents of Tm3＋ and different concentration ratios of Yb/Tm on the lumi- nescent properties of BaWO4：yb3＋/Tm3＋ nano-crystal synthesized by the hydrothermal metho...This research investigated the effect of different contents of Tm3＋ and different concentration ratios of Yb/Tm on the lumi- nescent properties of BaWO4：yb3＋/Tm3＋ nano-crystal synthesized by the hydrothermal method. The results indicated that lumines- cence intensity reached the strongest when CTm=1.0 mol.% and Cyb/CTm=2：1. X-ray diffraction revealed the tetragonal system of BaWO4：Yb3＋/Tm3＋ and the grain sizes were between 31 and 45 nm according to Scherrer equation. The results of X-ray diffraction and scanning electron microscopy were similar. Four emission peaks at 454, 475, 647 and 790 nm including two blue emission peaks and two red emission peaks, corresponding to ID2→3F4, 1G4→3H6, IG4→3F4 and 3H4→3H6 transitions of Tm3＋, were observed under excitation of 980 nm semiconductor laser. Blue emissions at 454 and 475 um were four-photon and three-photon absorption respec- tively in accordance with the relationship between luminescence intensity and pump power.展开更多
An efficient near-infrared （NIR） downconversion （DC） by converting broadband ultraviolet （UV） into NIR was demon- strated in YVO4：Tma＋,yb3＋ phosphors. The phosphors were extensively characterized using variou...An efficient near-infrared （NIR） downconversion （DC） by converting broadband ultraviolet （UV） into NIR was demon- strated in YVO4：Tma＋,yb3＋ phosphors. The phosphors were extensively characterized using various methods such as X-ray diffrac- tion, photoluminescence excitation, photoluminescence spectra and decay lifetime to provide supporting evidence for DC process. Upon UV light varying from 260 to 350 nm or blue light （473 nm） excitation, an intense NIR emission of Yb3＋ corresponding to tran- sition of 2Fs/2/5→2F7/2 peaking at 985 nm was generated. The visible emission, the NIR mission and the decay lifetime of the phosphors of various Yb3＋ concentrations were investigated. Experimental results showed that the energy transfer from vanadate group to Yb3＋ via Tm3＋ was very efficient. Application of the broadband DC YVO4：Tma＋,yb3＋ phosphors might greatly enhance response of sili- con-based solar cells.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
文摘采用水热法制备了Yb^(3+)/Tm^(3+)共掺Y2(Mo O _4)_3系列上转换发光粉。由于Tm^(3+)在980nm附近没有吸收,单掺Tm^(3+)的样品观测不到任何发射。引入Yb^(3+)后,借助Yb^(3+)对980nm红外光的吸收和Yb^(3+)到Tm^(3+)的能量传递,在可将光区观察到源自Tm^(3+)的蓝光和红光。这两个波段的发射随着Yb^(3+)和Tm^(3+)的浓度增加均呈现先增强后减弱的变化规律,8%和0.5%对应Yb^(3+)和Tm^(3+)的最佳掺杂浓度。上转换发射的功率关系研究表明,蓝、红光均为三光子过程,因此二者的产生过程为连续三步Yb^(3+)到Tm^(3+)的能量传递。
基金supported by National Natural Science Foundation of China Youth Science (20901011)Jilin Science and Technology Bureau (20091510)
文摘This research investigated the effect of different contents of Tm3＋ and different concentration ratios of Yb/Tm on the lumi- nescent properties of BaWO4：yb3＋/Tm3＋ nano-crystal synthesized by the hydrothermal method. The results indicated that lumines- cence intensity reached the strongest when CTm=1.0 mol.% and Cyb/CTm=2：1. X-ray diffraction revealed the tetragonal system of BaWO4：Yb3＋/Tm3＋ and the grain sizes were between 31 and 45 nm according to Scherrer equation. The results of X-ray diffraction and scanning electron microscopy were similar. Four emission peaks at 454, 475, 647 and 790 nm including two blue emission peaks and two red emission peaks, corresponding to ID2→3F4, 1G4→3H6, IG4→3F4 and 3H4→3H6 transitions of Tm3＋, were observed under excitation of 980 nm semiconductor laser. Blue emissions at 454 and 475 um were four-photon and three-photon absorption respec- tively in accordance with the relationship between luminescence intensity and pump power.
基金Project supported by the National Key Basic Research Program of China (2013CB921800)the National Natural Science Foundation of China (11074245, 11204292, 11274299)the Fundamental Research Funds for the Central Universities (WK2030020022)
文摘An efficient near-infrared （NIR） downconversion （DC） by converting broadband ultraviolet （UV） into NIR was demon- strated in YVO4：Tma＋,yb3＋ phosphors. The phosphors were extensively characterized using various methods such as X-ray diffrac- tion, photoluminescence excitation, photoluminescence spectra and decay lifetime to provide supporting evidence for DC process. Upon UV light varying from 260 to 350 nm or blue light （473 nm） excitation, an intense NIR emission of Yb3＋ corresponding to tran- sition of 2Fs/2/5→2F7/2 peaking at 985 nm was generated. The visible emission, the NIR mission and the decay lifetime of the phosphors of various Yb3＋ concentrations were investigated. Experimental results showed that the energy transfer from vanadate group to Yb3＋ via Tm3＋ was very efficient. Application of the broadband DC YVO4：Tma＋,yb3＋ phosphors might greatly enhance response of sili- con-based solar cells.
