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Dynamics of the host-sensitization by energy transfer from the self-trapped excitons and fabrication of novel white phosphors

Dynamics of the host-sensitization by energy transfer from the self-trapped excitons and fabrication of novel white phosphors
自俘获激子能量转移的主体敏化动力学和新型白色荧光粉的制造
批准号:
21360315
负责人:
KODAMA Nobuhiro
金额:
$8.82万
依托单位:
依托单位国家:
日本
项目类别:
Grant-in-Aid for Scientific Research (B)
财政年份:
2009
资助国家:
日本
项目状态:
已结题
起止时间:
2009 至 2011

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中文摘要
翻译
我们一直在寻找对稀土离子(Gd^<3+>, Tb^<3+>, Eu^<3+>和Pr^<3+>)具有增敏效应的新型真空紫外(VUV)激发材料,以实现白色荧光粉。在本研究中,我们研究了硼酸钪(LaSc_3(BO_3)_4 (LSB))和磷酸盐(Li_3Sc_2 (PO_4)_3 (LSP), K_3Sc (PO_4)_2 (KSP), K_2CsSc(PO_4)_3 (KCSP))和氟锆酸盐(LaZr_2F_11 (LZF)),其中宿主对VUV光的吸收可能导致有效的能量转移到稀土离子(Gd^<3+>, Tb^<3+>, Eu^<3+>和Pr^<3+>)。我们观察了自困激子(STE)向Gd^<3+>、Tb^<3+>和Eu^<3+>离子的能量转移,并确定了它们的动力学。在本研究中得到的结果如下。(1)发现硼酸钪(LaSc_3(BO_3)_4(LSB))和磷酸盐(Li_3Sc_2(PO_4)_3(LSP)、K_3Sc(PO_4)_2(KSP)、K_2CsSc(PO_4)_3 (KCSP))和氟锆酸盐(LaZr_2F_11(LZF))在紫外可见区表现出寄主辐射,并测定了它们的寿命。宿主辐射被认为是由于BO_3^<3->或PO_4^<3->基团的带隙激发或分子内跃迁而产生的STEs。Gd^<3+>, Tb^<3+>和Eu^<3+>被宿主激发(STEs)的能量转移所敏化,并在这些材料中确定了它们的动力学。(2)在紫外激发下,未掺杂的LSB在315和366 nm处表现出本征宽发射带。在315 nm处峰值的主发射可以归因于STE的重组,这可能与带隙激发或BO_3^<3->基团的分子跃迁有关。在Gd^<3+>和Tb^<3+>掺杂样品(LSB: Gd和LSB: Tb)中,宿主发射随Gd^<3+>或Tb^<3+>浓度的增加而降低(5-50 at)。%),这伴随着Gd^<3+>或Tb^<3+>跃迁的增加。这表明从宿主到Gd^<3+>离子的有效能量转移。此外,在Gd^<3+>-或Tb^<3+>-掺杂样品中,随着Gd^<3+>或Tb^<3+>浓度的增加,宿主发射的衰减时间减小。这一发现为LSB: Gd和LSB: Tb从STE到Gd^<3+>或Tb^<3+>的能量转移提供了进一步的证据。通过时间分辨测量,确定了从STE到Gd^<3+>和Tb^<3+>的能量转移率。这些观测到的速率在估计的偶极子-偶极子能量转移速率的一个数量级之内。确定了宿主排放物的温度依赖性。结果表明,从STE到Gd^<3+>和Tb^<3+>的能量转移可能是由于激子迁移而热激活的。(3) Gd^<3+>掺杂的LSP和KSP在VUV激发下也观察到自困激子(STE)的能量转移。宿主到gd ^<3+>的能量转移动力学。得到了主发射光谱(归属于STE)和激发光谱,以及在157 nm处激发的时间分辨发射光谱。从时间分辨测量,宿主的能量传输速率。到gd ^<3+>是确定的。从估计的偶极子-偶极子能量转移率与实验测量的辐射强度的温度依赖性比较,表明从STE到Gd^<3+>的热激活能量转移过程与LSB: Gd和LSB: Tb一样发生。(4) GdPO_4: Tb^<3+>和Sr_3Gd(PO_4)_3: Tb^<3+>和Na_2GdF_2PO_4: Tb^<3+>在主晶格和Tb^<3+> 4f^8-4f^7-5d激发下均观察到明显的量子切割。在Tb^<3+> 4f^75d态激发后,能量通过一对Tb^<3+>之间的交叉弛豫过程转移。Tb^<3+>和/或Tb^<3+>。Gd ^ < 3 + >;在VUV区主晶格激发后,激发能要么直接转移到4f^75d态的Tb^<3+>,要么先转移到Gd^<3+>的^6G能级,然后再转移到4f^75d态的Tb^<3+>,然后通过交叉弛豫能转移到Tb^<3+> 4f^7-5d态的弛豫能。在Na_2GdF_2PO_4: Eu_<3+>中观察到从Gd^<3+>到Eu^<3+>和Eu^<3+>到Eu^<3+>的有效能量转移。少
英文摘要
We have been searching for new vacuum ultraviolet (VUV)-excited materials that exhibit a sensitization effect for rare-earth ions (Gd^<3+>, Tb^<3+>, Eu^<3+>, and Pr^<3+>) toward realizing white phosphors. In this study, we investigate scandium borate (LaSc_3(BO_3)_4 (LSB)) and phosphates (Li_3Sc_2 (PO_4)_3 (LSP), K_3Sc (PO_4)_2 (KSP), K_2CsSc(PO_4)_3 (KCSP)), and fluorozirconate (LaZr_2F_11 (LZF)), in which the absorption of VUV light by the host may lead to efficient energy transfer to rare-earth ions ( Gd^<3+>, Tb^<3+>, Eu^<3+> , and Pr^<3+> ). We observed energy transfer from the self-trapped exciton (STE) to Gd^<3+>, Tb^<3+>, and Eu^<3+> ions and we determined their dynamics. In this research the results obtained are as follows.(1) Scandium borate (LaSc_3(BO_3)_4(LSB)) and phosphates(Li_3Sc_2(PO_4)_3(LSP), K_3Sc(PO_4)_2(KSP), K_2CsSc(PO_4)_3 (KCSP)), and fuluorozirconate (LaZr_2F_11(LZF)) have been found to exhibit host emission in the UV-visible region and the lifetimes of these h … More ost emissions have been determined. The host emissions have been ascribed to STEs which are derived from band gap excitations or intramolecular transitions of the BO_3^<3-> or PO_4^<3-> group. Sensitizations of the Gd^<3+>, Tb^<3+>, and Eu^<3+> by energy transfer from the host excitations (STEs) have been demonstrated and their dynamics have been determined in these materials.(2) Under VUV-excitation, undoped LSB exhibits intrinsic broad emission bands at 315 and 366 nm. The host emission with a peak at 315 nm can be assigned to recombination of the STE that could be associated with band-gap excitations or molecular transitions with the BO_3^<3-> group. In Gd^<3+>-and Tb^<3+>-doped samples (LSB : Gd and LSB : Tb), host emission decreases with increasing Gd^<3+> or Tb^<3+> concentration (5-50 at.%) and this is accompanied by an increase in the transition of Gd^<3+> or Tb^<3+>. This suggests efficient energy transfer from the host to Gd^<3+> ions. In addition, in the Gd^<3+>-or Tb^<3+>-doped samples the decay time of the host emission decreases with increasing Gd^<3+> or Tb^<3+> concentration. This finding provides further evidence for energy transfer from the STE to Gd^<3+> or Tb^<3+> in LSB : Gd and LSB : Tb. From time-resolved measurements, the energy transfer rates from the STE to Gd^<3+> and Tb^<3+> were determined. These observed rates are within an order of magnitude of the estimated dipole-dipole energy transfer rates. The temperature dependences of the host emissions were determined. It was demonstrated that the energy transfers from STE to Gd^<3+> and Tb^<3+> are thermally activated probably due to exciton mobility.(3) Energy transfer from the self-trapped excitons (STE) upon VUV excitation was also observed in Gd^<3+>-doped LSP and KSP. The dynamics of the host-to-Gd^<3+> energy transfer. The host emission (ascribed to STE) and excitation spectra, as well as time-resolved emission excited at 157 nm were obtained. From time-resolved measurements, the energy transfer rate of the host.to-Gd^<3+> are determined. From a comparison of estimated dipole-dipole energy transfer rate with the experimentally measured temperature dependence of emission intensity, it was suggested that a thermally activated energy transfer process from the STE to Gd^<3+> occurs as with LSB : Gd and LSB : Tb.(4) Visible quantum cutting was observed in GdPO_4 : Tb^<3+> and Sr_3Gd(PO_4)_3 : Tb^<3+>, and Na_2GdF_2PO_4 : Tb^<3+> upon the host lattice and Tb^<3+> 4f^8-4f^7-5d excitations. Upon excitation at the Tb^<3+> 4f^75d state, then energy transfers via a cross relaxation process between a pair of Tb^<3+>.Tb^<3+> and/or Tb^<3+>.Gd^<3+> ; upon host lattice excitation in the VUV region, the excitation energy either directly transfers to a Tb^<3+> in its 4f^75d state or first transfer to the ^6G level of Gd^<3+> then to Tb^<3+> in its 4f^75d state, then relaxes via cross relaxation energy transfer as that excited at Tb^<3+> 4f^7-5d state. An efficient energy transfer from Gd^<3+> to Eu^<3+> and Eu^<3+> to Eu^<3+> was observed in Na_2GdF_2PO_4 : Eu_<3+>. Less
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LaSc_3(BO_3)_4におけるホスト励起からGd^<3+>へのエネルギー移動:ダイナミクスと温度依存
LaSc_3(BO_3)_4 中从主体激发到 Gd^<3+> 的能量转移:动力学和温度依赖性
DOI: --
发表时间: 2011
期刊:
影响因子: --
作者: [田丸英明, 高橋智子, 小玉展宏]
通讯作者: 小玉展宏
Photoluminesence prpoties of Na_2GdF_2PO_4:Re(Re=Eu^<3+>, Tb^<3+>)underVUV-UV excitation
Na_2GdF_2PO_4:Re(Re=Eu^<3 >, Tb^<3 >)在VUV-UV激发下的光致发光特性
DOI: --
发表时间: 2010
期刊: J.Electrochemical Society
影响因子: --
作者: [C.L.Chen, H.Furusho, H.Mori, Nobuhiro Kodama]
通讯作者: Nobuhiro Kodama
DOI: --
发表时间: 2009
期刊:
影响因子: --
作者: [滝上元気, 高橋智子, 小玉展宏]
通讯作者: 小玉展宏
蛍光体を用いた波長変換材料-白色LED・太陽電池への応用を中心として-
使用荧光体的波长转换材料 - 专注于白色 LED 和太阳能电池的应用 -
DOI: --
发表时间: 2012
期刊:
影响因子: --
作者: [穴田智史, 永瀬丈嗣, 保田英洋, 森博太郎, 小玉展宏(分担)]
通讯作者: 小玉展宏(分担)
7
    Quantum cutting localaized emission from the excitons in photonic crystals fabricated by femtosecond laser
    • 批准号:
      23656393
    • 项目类别:
      Grant-in-Aid for Challenging Exploratory Research
    • 资助金额:
      $2.5万
    • 财政年份:
      2011
    • 负责人:
      KODAMA Nobuhiro
    • 依托单位:
    Development of VUV-excited phosphors based on correlation between quantum cutting and acceptor-site arrangement within coordination
    • 批准号:
      17360317
    • 项目类别:
      Grant-in-Aid for Scientific Research (B)
    • 资助金额:
      $10.3万
    • 财政年份:
      2005
    • 负责人:
      KODAMA Nobuhiro
    • 依托单位:
    Quantum cutting through downconversion in rare-earth compounds by crystal-field control
    • 批准号:
      14550662
    • 项目类别:
      Grant-in-Aid for Scientific Research (C)
    • 资助金额:
      $2.62万
    • 财政年份:
      2002
    • 负责人:
      KODAMA Nobuhiro
    • 依托单位:
    Optical energy storage-type tunable long-lasting phosphorescence of low valent rare-earth ions using crystal-field distributions
    • 批准号:
      12650665
    • 项目类别:
      Grant-in-Aid for Scientific Research (C)
    • 资助金额:
      $2.24万
    • 财政年份:
      2000
    • 负责人:
      KODAMA Nobuhiro
    • 依托单位:
    海外基金