共沉淀法制备Y_2O_2S∶Eu^(3+),Mg^(2+),Ti^(4+)红色长余辉材料

用共沉淀法制备了Y2O2S∶Eu3+,Mg2+,Ti4+红色长余辉材料。测量了材料的电子显微形貌、晶体结构和发射光谱。通过与固相法制备的Y2O2S∶Eu3+,Mg2+,Ti4+长余辉材料比较,发现两种方法都可以制备粒度基本相同的纯相Y2O2S基质晶体,但共沉淀法样品的颗粒结构更松散。研究了Eu3+浓度对两种方法制备样品的谱线发射强度的影响,通过比较共沉淀法和高温固相法制备的样品中Eu3+的5D1→7F3较高能级跃迁的587.6 nm谱线强度随Eu3+浓度的变化,发现共沉淀法更有利于Eu3+均匀进入Y2O2S基质晶格而形成有效的发光中心。

Ti^(4+)的掺入对Y_2O_2S:Eu^(3+),Mg^(2+),Ti^(4+)陷阱分布和余辉性能的影响

用高温固相法制备了不同Ti4+掺杂量的红色长余辉材料Y2O2S:Eu3+,Mg2+,Ti4+,其X射线衍射分析、发射光谱和激发光谱均不受Ti4+掺杂量改变的影响.测量了Ti4+掺杂量不同的样品的热释光谱,随着Ti4+掺杂量的增加,热释光的峰值强度先增强后减弱,有了很大的变化;用PeakFit软件以一般阶动力学模型对Ti与Y2O2S的物质的量比分别为0.5%,2.5%和8.0%的样品进行了热释光曲线拟合,得出了它的单峰曲线并计算了与其对应的陷阱参数.陷阱分布表明:当Ti掺杂量为2.5%时,有利于合适深度陷阱的大量形成,从而使材料的发光和余辉性能得到了很大的提高.

EDTA络合溶胶-凝胶法制备Y_2O_2S:Eu^(3+),Mg^(2+),Ti^(4+)红色长余辉材料

采用EDTA(乙二胺四乙酸)络合溶胶-凝胶法制备了Y2O2S:Eu3+,Mg2+,Ti4+粉体。采用X射线衍射仪、扫描电子显微镜和荧光分光光度计对不同温度合成的样品性能进行测试与表征。结果表明:当硫化温度低于1 000℃时,样品为Y2O3与Y2O2S的混合相;当温度在1 050～1 100℃时,样品为纯相的Y2O2S;当温度升高到1 150℃时,再次出现Y2O3的相。硫化温度在950～1 100℃时,产物的粒径为50～300 nm。用波长为330 nm的紫外光激发样品时,626 nm处的发射对应于Eu3+的5D0-7F2跃迁。硫化温度为1 100℃时,样品的余辉时间最佳,为95 min(≥1 mcd/m2)。相比于以乙酰丙酮为络合剂的溶胶-凝胶法,EDTA络合溶胶-凝胶法制备的样品的发光性能具有较大提高。

Y_2O_2S∶Eu^(3+),Mg^(2+),Ti^(4+)长余辉材料制备中烧结条件和助熔剂的影响

采用高温固相法合成了Y2O2S∶Eu3+,Mg2+,Ti4+红色长余辉材料。通过X射线衍射分析和扫描电镜测试技术研究了样品的晶体结构和颗粒的大小、形貌,分析了有助于晶体颗粒生长的烧结温度、气氛以及助熔剂对它的影响,还对荧光体的发光光谱、相对亮度、余辉性质进行了研究。结果表明,制备得到的Y2O2S∶Eu3+,Mg2+,Ti4+红色长余辉材料体系相态纯净,有较完整和均匀的晶形,完整的晶体结构有利于提高荧光体的发光性质。制备中合适的烧结温度为1 150℃,要选择弱还原气氛。加入L i3PO4可以使晶体颗粒的晶型完整,粒径增大,并且粒度分布较窄。

水热法制备Y_2O_2S∶Dy^(3+),Mg^(2+),Ti^(4+)白色长余辉微纳米材料及发光性能

采用水热法制备了白色长余辉微纳米发光材料Y2O2S∶x Dy3+,Mg2+,Ti4+(x=0.5%,1.0%,1.5%,2.0%,2.5%),利用X射线粉末衍射(XRD)、扫描电镜(SEM)、激发和发射光谱、色度坐标、余辉曲线和热释光谱对样品进行表征。结果表明:煅烧后,样品的形貌为颗粒状,其粒径在150~250 nm之间;在359 nm的紫外光激发下,样品在488 nm和579 nm处有两个很强的发射峰,它们分别对应于Dy3+的蓝色跃迁(4F9/2→6H15/2)和黄色跃迁(4F9/2→6H13/2),适当比例的黄光和蓝光混合可以产生白光;当Dy3+浓度为2.0%(摩尔分数)时,样品的余辉性能最佳,用254 nm的低压汞灯照射10 min后,余辉时间可达到3600 s(≥1 mcd/m2)以上,与同样温度下高温固相法或溶胶凝胶法所制备样品的相比,其余辉性能得到了很大改善。

掺杂离子对白色长余辉发光材料Y_2O_2S：Tb^3＋,Eu^3＋,M^2＋(M=Mg,Ca,Sr,Ba),Zr^4＋性能的影响

采用高温固相法制备了白色长余辉发光材料Y2O2S∶Tb3+,Eu3+,M2+(M=Mg,Ca,Sr,Ba),Zr4+,利用X晶体衍射、发光光谱、余辉曲线和热释光曲线等对制备的材料进行表征。结果表明:掺杂离子没有改变样品晶体结构和发射峰的位置,但对其发光强度、余辉时间及陷阱深度有较大的影响。在263 nm紫外光的激发下,469 nm和626 nm的发射分别对应于Eu3+的5D2→7F0、5D0→7F2跃迁,544 nm的发射对应于Tb3+的5D4→7F5跃迁,主要通过它们的混合产生白光。掺杂不同二价离子样品的余辉性能按Mg2+、Sr2+、Ca2+、Ba2+的顺序递减,其中掺杂Mg2+的样品,色度坐标为(0.29,0.32),陷阱深度为1.17 eV,余辉时间长达320 s(≥1 mcd/m2),表现出最佳的发光性能。

Characterization of Y_2O_2S∶Eu ^(3+), Mg^(2+), Ti^(4+) Long-Lasting Phosphor Synthesized by Flux Method

Long-lasting phosphor Y2O2S ： Eu^3＋ , Mg^2＋ , Ti^4＋ was synthesized by a flux method and their luminescence properties were investigated. The result indicates that the unit cell parameter c is linearly increased with the increase of Eu2O3 content in Y2O2S： Eu^3＋ （0.01 ≤ x ≤0.10）. On the other hand, the change of unit cell parameter a is not linear dependence. In the Y2O2S： Eu^3 ＋ crystal structure, Eu^3＋ ions only replaced Y^3 ＋ ions＇ places in which it posited center position of c axis. With the increase of Eu2O3 content, the position of the strongest emission peak changed from 540 nm （5D1→^ 7F2 transition） to 626 nm （^5Do→^7TF2 transition）, and the maximum intensity was obtained when x = 0.09 in Y2O2S： Eu^3＋ （0.01 ≤x ≤0.10）. This is due to the environment of trivalent europium in the crystal structure of Y2O2S. Doping with Mg^2＋ or Ti^4＋. ions alone cannot get the good long-lasting afterglow effect, whereas co-doping with Mg^2 ＋ and Ti^4 ＋ ions and excited with 365 nm ultraviolet light, a strong thermoluminesence peak appeared, red and orange long-lasting phosphorescence （LLP） was also observed and the phosphorescence lasted nearly 3 h in the light perception of the dark-adapted human eye （0.32 mcd·m^-2）. Thus the LLP mechanism was analyzed.

Co-Precipitation Synthesis and Spectral Characteristics of Long Afterglow Phosphor Y_2O_2S:Sm^(3+), Mg^(2+), Ti^(4+)

Y2O2S：Sm^3＋, Mg^2＋, Ti^4＋ phosphor was synthesized by co-precipitation method. The crystalline structure of all synthesized phosphors was investigated by XRD. The result showed that all synthesized phosphors had a hexagonal crystal structure, which was the same as Y2O2S. The emission spectrum and excitation spectrum were measured, and the effect of Sm^3 ＋ molar ratio on the spectra was discussed. The emission spectra of the phosphors showed three emission peaks due to typical transitions of Sm^3 ＋ （4G5/2→6HJ ,J = 5/2, 7/2, 9/2）, and the emission peaks at 606 nm was stronger than others. With the increase of Sm^3 ＋ molar ratio, the emission intensity was strengthened. The excitation peaks were ascribed to the representative energy transition 4f→4f of Ti^4＋ phosphor prepared by co-precipitation method was Sm^3＋ ions. The results indicated that the Y2O2S ： Sm^3＋ , Mg^2＋ , an efficient long afterglow phosphor.

Ga_2S_3∶Eu^(2+)和SrGa^(2+x)S_(4+y)∶Eu^(2+)系列荧光粉的发光性能研究

采用高温固相法合成了Ga2S3∶Eu2+和SrGa2S4∶Eu2+系列荧光粉。发现Ga2S3∶Eu2+的发射峰位于570nm附近,SrGa2S4∶Eu2+的发射峰位于535nm附近。同时进一步探讨了SrGa2+xS4+y∶Eu2+体系中,过量的Ga对发光的影响,通过漫反射光谱和XRD谱确定过量的Ga是以Ga2S3的形式存在于SrGa2S4相中;通过荧光光谱发现过量的Ga并不引起SrGa2S4∶Eu2+发射峰的位移,而是增强其在400～520nm处激发峰的强度,从而增强Eu2+在535nm处的发光强度。

红色Y_2O_2S:Eu^(3+)磷光材料的沉淀法制备和发光性能研究

用沉淀法制备了Eu3+掺杂的Y2O2S磷光材料,测量并研究了掺杂不同物质的量的Eu3+离子的Y2O2S磷光材料的发射谱和激发谱.发射光谱对应了Eu3+离子5DJ(J=0,1,2,3)-7FJ(J=0,1,2,3,4)的特征发射,激发光谱主峰对应260,345,468,540nm等,余辉时间(到人眼的最小亮度分辨率0.32mcd/m2)可达1h以上.

红色蓄光材料Y_2O_2S∶Eu^(3+)的硫熔法制备及其发光性能

用硫熔法制备了系列红色蓄光材料Y2O2S∶Eu3x+(0.01≤x≤0.10)的多晶粉末样品并系统研究了其发光特性。XRD结果表明,晶胞参数c随着Eu3+含量的逐渐增大而增大,而晶胞参数a没有明显的线性变化关系,这与Y2O2S∶Eu3+的晶体结构有关。Y2O2S∶Eux3+(0.01≤x≤0.10)的激发光谱相似,在626nm发射光监控下最大激发波长约在330nm附近。在330nm激发下,随着Eu3+含量逐渐增大,发射光谱最强发射峰位置从540nm右移至626nm,观察到红色特征发射峰626nm的强度逐渐增大,在Eu3+含量为0.09时,其强度达到最大。在最佳合成条件及最佳Eu3+含量下,正在进行掺杂Mg2+和Ti4+及其发光特性的研究。

纳米粉体Y_2O_3:Ti^(3+),Eu^(3+)的光谱性能

采用共沉淀法在氮氢气氛中制备出Y_2O_3:Ti^(3+),Eu^(3+)纳米粉体,测量了它的XRD、激发与发射光谱,观测了形貌。通过与Y_2O_3:Ti^(3+)纳米粉体的光谱比较分析,发现Y_2O_3中的Ti^(3+)至Eu^(3+)存在能量传递,以致紫外至蓝光区域的光,均能使Eu^(3+)经~5D_0→~7F_2等跃迁通道发射出610 nm左右的荧光,于是增强了粉体在红橙光区发光的比重,因此可以调节粉体的发光性能。Y_2O_3:Ti^(3+),Eu^(3+)纳米粉体的吸收带从紫外延伸到蓝光区,强荧光带覆盖了整个可见光区,这预示它有望成为新一代白光LED或汞灯的光转换荧光粉。

Y2O2S：Eu^3＋红色荧光粉的SnO2：Sb包覆研究

采用硫融法合成了Y2O2S：Eu^3＋红色荧光粉。用溶胶-凝胶法在其表面包覆了一层SnO2：Sb透明导电薄膜。通过x射线衍射（XRD）、透射电镜（TEM）、荧光光谱（PL）和电阻测量等检测手段分别分析了包覆处理对Y2O2S：Eu^3＋的晶体结构、表面形貌、荧光性质以及荧光粉导电性的影响。结果表明：通过该方法成功地在Y2O2S：Eu^3＋表面包覆了一层连续的SnO2：Sb薄膜；当包覆量nSoO2/nY2O2S=6％时，所得到的荧光粉同时具有较高的荧光强度和导电性；当掺杂量DSb/nSn=10％，退火温度为500℃（氧气流中退火1h）时，可以得到导电性较好的荧光粉。

碱土金属离子对红色长余辉材料Y2O2S∶Eu3+,M2+ (M=Mg,Ca,Sr,Ba),Ti4+纳米阵列发光性能的影响

采用溶胶凝胶模板法制备红色长余辉发光材料Y2O2S∶Eu3+,M2+(M=Mg,Ca,Sr,Ba),Ti4+纳米阵列,利用X射线衍射、扫描电子显微镜和荧光分光光度计、照度计分别研究了不同二价离子掺杂下所合成样品的物相、形貌及发光性能。结果表明:样品排列整齐有序,管径大小统一;不同的二价离子种类没有改变晶体结构和发射峰的位置,但对余辉性能有较大的影响。用324 nm波长光激发样品,由于Eu3+的5D0→7F2跃迁,最强的红色发射峰位于626 nm处;不同离子掺杂样品的余辉性能按Ba2+、Ca2+、Sr2+、Mg2+的顺序递加,其中二价离子为Mg2+时,余辉时间长达287 s(≥1 mcd/m2),表现出最佳的余辉性能。

纳米Y_2O_2S:Eu^(3+)红色荧光粉的间接法制备及发光性质

用间接法制备纳米级红色荧光粉Y2O2S:Eu3+(物质的量之比为Eu3+/Y3+=0.02)。XRD测试表明,制得纳米级的Y2O2S:Eu3+为单一纯相。透射电子显微镜(TEM)扫描结果显示纳米材料的平均颗粒尺寸为30 nm,与Debye-Scherre公式计算的结果基本一致。荧光光谱中,激发光谱分为3个区域,200-280 nm的区域为Y2O2S基质的激子激发带,峰值为262 nm;280-380 nm的区域属于Eu3+→O2-(S2-)的电荷迁移带,峰值为319 nm;而位于399 nm和472 nm的线状光谱则属于Eu3+的4 f组态内部电子之间的跃迁。

Ln_7O_6(BO_3)(PO_4)_2∶Eu(Ln=La,Gd,Y)的VUV-UV激发和辐射发光

本文报道了Ln7O6(BO3) (PO4 ) 2 ∶Eu(Ln =La ,Gd ,Y)在VUV UV区的激发光谱及Eu3 + 在可见区的发射光谱。其激发光谱包括基质在真空紫外区的激发带和激活剂离子在紫外区的Eu3 + O2 -电荷迁移带 ,随La3 + ,Gd3 + ,Y3+ 离子半径逐渐减小 ,Eu3 + O2 -电荷迁移带的重心位置逐渐向高能量方向移动 ,Gd7O6(BO3) (PO4 ) 2 ∶Eu和Y7O6(BO3) (PO4 ) 2 ∶Eu在真空紫外区的吸收与Eu3+ O2 -电荷迁移带位于紫外区的吸收的比值要高于在La7O6(BO3) (PO4 ) 2 ∶Eu中的这个比值。激发能可被基质吸收 ,传递给激活剂离子 ,得到Eu3 + 的红光发射。在Gd7O6(BO3) (PO4 ) 2 ∶Eu中 ,5D0 →7F1的发射强度较强 ,在Y7O6(BO3) (PO4 ) 2 ∶Eu中 ,5D0→7F2 和5D0 →7F3的跃迁较强。

Vacuum Ultraviolet Excited Photoluminescence Properties of Y_2O_2S:Eu^(3+),Bi^(3+) Phosphor

As an Hg-free lamp using phosphor, the Bi^3＋ and EH^3＋ co-doped Y2O2S phosphors were prepared and their luminescence properties under vacuum ultraviolet（VUV） excitation were investigated. The VUV photoluminescent intensity of Y2O2S：Eu^3＋ was weak, however, considerably stronger red emission at 626 nm with good color purity was observed in Y2O2S：Eu^3＋,Bi^3＋ systems. Investigation on the photoluminescence reveals that the strong VUV luminescence of Y2O2S：Eu^3＋,Bi^3＋ at 147 nm is mainly because the Bi^3＋ acts as a medium and effectively performs the energy transfer process： Y^3＋-O^2-→Bi^3＋→Eu^3＋, while the intense emission band at 172 nm is attributed to the absorption of the characteristic ^1So-^1P1 transition of Bi^3＋ and the direct energy transfer from Bi^3＋ to Eu^3＋. The Y2O2S：Eu^3＋,Bi^3＋ shows excellent VUV optical properties compared with the commercial （Y,Gd）BO3：Eu^3＋. Thus, the Y2O2S：Eu^3＋,Bi^3＋ can be a potential red VUV-excited candidate applied in Hg-free lamps for backlight of liquid crystal display.

Effects of Doping Trace Sm^(3+) and Gd^(3+) on Luminescent Character of Y_2O_2S∶Eu^(3+)

After trace Sm^3＋ ions and Gd^3＋ ions doping, the emission intensity of red phosphors Y2O2S： Eu^3 ＋ was enhanced and the voltage character （relation between emission intensity and excitation voltage） was improved while the other properties of physics and chemistry were not changed. The origins of enhancement and improvement are discussed. Probably the distortion and the defect of crystals are decreased by the substitution of Gd^3＋ for Y^3＋ instead of Eu^3＋ for Y^3＋ , and thus the Eu^3＋ crystal field is improved, and radiationless process and energy loss resulted from crystal defect are weakened, which leads to increased luminescence intensity and voltage character improvement. The overlapping fluorescent spectra of Y2O2S： Sm^3＋ emission and Y2O2S：Eu^3＋ excitation as well as Eu^3 ＋ excitation spectra transitions spectra lead to energy transfer from Sm^3 ＋ sensitization of Sm^3＋ ions fectively. containing Sm^3＋ excitation the possibility of resonance ions to Eu^3＋ ions, and the to Eu^3＋ ions is achieved effectively.

Optical performance study of Sr_2ZnSi_2O_7:Eu^(2+),Dy^(3+), SrAl_2O_4:Eu^(2+),Dy^(3+) and Y_2O_2S:Eu^(3+),Mg^(2+),Ti^(4+) ternary luminous fiber

In this study, down-conversion fluorescent powder of Sr2ZnSi2O7：Eu-（2＋）,Dy-（3＋）, SrAl2O4：Eu-（2＋）,Dy-（3＋） and Y2O2S：Eu-（3＋）,Mg-（2＋）,Ti-（4＋）, which were the common three primary colors materials with long afterglow, were synthesized by high temperature solid state method. The blends of rare earth（RE） luminescent materials have been of interest to reinvest the luminescent characteristics of polyethylene terephtahalate（PET） luminous fiber. The scanning electron microscopy（SEM） and an inversion fluorescence microscope were used to characterize the surface morphology and the dispersion of inclusion. Through analysis of microcosmic morphology, three typical dispersions of luminescent particles were summarized. The X-ray diffraction indicated that the phase structure of fiber samples and crystal structure of luminescence materials kept complete after prilling and spinning. From the fluorescence spectra and CIE 1931 coordinates, it could be found that different combinations of luminous fibers were desired to obtain divers colors emission luminous fiber. And the fiber samples were a light sensation which could induct different excitation wavelengths and convert it down to different colors. The afterglow decay curve and its differential curve were summarized indicating the three decay stages. The decay curve and decay rate curve showed that the contents of Sr2ZnSi2O7：Eu-（2＋）,Dy-（3＋）, SrAl2O4：Eu-（2＋）,Dy-（3＋） and Y2O2S：Eu-（3＋）,Mg-（2＋）,Ti-（4＋） had obvious influence on the afterglow of fiber samples.

原材料Y_2O_3的结晶性对Y_2O_2S∶Eu^(3+)发光特性的影响

为进一步提高Y2O2S∶Eu3+的发光性能,采用改善主要原材料Y2O3结晶性的方法,使Y2O2S∶Eu3+红色荧光粉在20 kV和25 kV下发光强度分别增强5%和10%,且不影响色度、粒度、粉体分散性等主要考核指标。提高了粉体的耐电压特性(发射强度与激发电压间的关系特性)。讨论和分析了发射强度增强、电压特性改善的原因:主要原材料Y2O3的结晶性的改善,使得合成的Y2O2S∶Eu3+具有更好的晶体质量,Eu3+离子晶场环境得到进一步改善,从而减弱了无辐射过程及因晶格畸变所造成的能量损失,发光效率得到增强,电压特性得到改善。实验表明,获取高质量多晶Y2O3的最佳分解温度为1400℃左右。