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
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
中文摘要
为了实现白色荧光体,我们一直在寻找对稀土离子(Gd^3+>、Tb^3 +>、Eu^3 +>和Pr^3+>)表现出敏化效果的新的真空紫外(VUV)激发材料。在这项研究中,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)),其中基质对真空紫外光的吸收可以导致能量有效地转移到稀土离子(Gd^<3+>、Tb^<3+>、Eu^<3+>和Pr^<3+>)。我们观察到从自陷激子(STE)到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,所获得的结果如下。(1)硼酸钪(LaSc_3(BO_3)_4(LSB))、磷酸钪(Li_3Sc_2(PO_4)_3(LSP)、K_3Sc(PO_4)_2(KSP)、K_2CsSc(PO_4)_3(KCSP))和氟锆酸钪(LaZr_2F_11(LZF))在紫外-可见光范围内具有基质发光,它们的寿命分别为100 nm和200 nm,它们的发光强度分别为100 nm和200 nm。 关于我们 已经确定了ost排放量。基质发光被认为是BO_3 ~(2-)或PO_4 ~(2-)基团的带隙激发或分子内跃迁产生的STE<3-><3->。Gd^<3+>、Tb^<3+>和Eu^<3+>通过来自主体激发态(STE)的能量转移的敏化作用已经被证明,并且它们的动力学已经在这些材料中被确定。(2)在VUV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处有一个峰值的主体发射可以归因于STE的复合,这可能与BO_3 ~+基团的带隙激发或分子跃迁有关<3->。在Gd^<3+>和Tb^<3+>掺杂的样品(LSB:Gd和LSB:Tb)中,随着Gd^<3+>或Tb^<3+>浓度的增加(5-50 at.%),基质发射降低并且这伴随着Gd^<3+>或Tb^<3+>跃迁的增加。这表明从主体到Gd^<3+>离子的有效能量转移。此外,在Gd^<3+>或Tb^<3+>掺杂的样品中,基质发射的衰减时间随Gd^<3+>或Tb^<3+>浓度的增加而减小。这一发现为LSB:Gd和LSB:Tb中从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+>的能量转移速率。这些观察到的速率在估计的偶极-偶极能量转移速率的数量级内。确定了宿主发射的温度依赖性。结果表明,从STE到Gd^<3+>和Tb^<3+>的能量传递是热激活的,这可能是由于激子迁移率的缘故。(3)在Gd^3+掺杂的LSP和KSP中也观察到了真空紫外激发下自陷激子(STE)的能量转移。宿主-Gd^<3+>能量转移的动力学。获得了主体发射(归因于STE)和激发光谱,以及在157 nm处激发的时间分辨发射。从时间分辨的测量中,确定了基质到Gd ^<3+>的能量转移速率。通过比较估计的偶极-偶极能量转移速率与实验测量的发射强度的温度依赖性,我们认为从STE到Gd^<3+>的热激活能量转移过程与LSB:Gd和LSB:Tb一样。(4)在GdPO_4:Tb^<3+>、Sr_3Gd(PO_4)_3:Tb^<3 +>和Na_2GdF_2PO_4:Tb^<3+>中,观察到了在基质晶格和Tb^<3+> 4f^8-4f^7-5d激发下的可见量子剪裁。在Tb^<3+> 4f^75d态激发时,能量通过一对Tb^<3+>.Tb^<3+>和/或Tb^<3+>.Gd^<3 +>之间的交叉弛豫过程转移;在VUV区域中的主晶格激发时,激发能要么直接转移到Tb^<3+>的4f^75d态,要么先转移到Gd^<3+>的^6G能级,然后转移到Tb^<3+>的4f^75d态。7 - 5d态激发后,与Tb^<3+> 4f^7-5d态激发时一样,通过交叉弛豫能量转移弛豫。在Na_2GdF_2PO_4:Eu_(3+)中观察到Gd^<3 +>与Eu ^<3+>和Eu^<3+>与Eu^<3 +>的有效能量传递。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
オルトリン酸塩における自己束縛励起子からGd^<3+>へのエネルギー移動とダイナミクス
正磷酸盐中自束缚激子到 Gd^<3+> 的能量转移和动力学
DOI:
--
发表时间:
2009
期刊:
影响因子:
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作者:
[滝上元気, 高橋智子, 小玉展宏]
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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)
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
Photoluminescence properties of Na_2GdF_2PO_4 :(Re=Eu^<3+> and Tb^<3+>) under VUV-UV excitation
Na_2GdF_2PO_4 :(Re=Eu^<3 > and Tb^<3 >)在VUV-UV激发下的光致发光性质
DOI:
--
发表时间:
2010
期刊:
J. Electrochemical Society
影响因子:
--
作者:
[D. Wang, N. Kodama, L. Zhao, Y. Wang]
通讯作者:
Y. Wang
共 7 条
Quantum cutting localaized emission from the excitons in photonic crystals fabricated by femtosecond laser
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批准号:23656393
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项目类别:Grant-in-Aid for Challenging Exploratory Research
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资助金额:$2.5万
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财政年份:2011
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负责人:KODAMA Nobuhiro
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依托单位:
Development of VUV-excited phosphors based on correlation between quantum cutting and acceptor-site arrangement within coordination
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批准号:17360317
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项目类别:Grant-in-Aid for Scientific Research (B)
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资助金额:$10.3万
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财政年份:2005
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负责人:KODAMA Nobuhiro
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依托单位:
Quantum cutting through downconversion in rare-earth compounds by crystal-field control
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批准号:14550662
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项目类别:Grant-in-Aid for Scientific Research (C)
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资助金额:$2.62万
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财政年份:2002
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负责人:KODAMA Nobuhiro
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依托单位:
Optical energy storage-type tunable long-lasting phosphorescence of low valent rare-earth ions using crystal-field distributions
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批准号:12650665
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项目类别:Grant-in-Aid for Scientific Research (C)
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资助金额:$2.24万
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财政年份:2000
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负责人:KODAMA Nobuhiro
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依托单位:
Fabrication and optical characterization of near UV-laser crystals using low-symmetry crystal field
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批准号:10650659
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项目类别:Grant-in-Aid for Scientific Research (C)
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资助金额:$0.58万
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财政年份:1998
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负责人:KODAMA Nobuhiro
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依托单位:
海外基金