LED用绿色荧光粉BaSi_2N_2O_2:Eu^(2+)的发光和封装性能

采用高温固相法合成了白光LED用蓝绿色荧光材料BaSi2N2O2∶Eu2+。用X射线衍射(XRD)、光致发光(PL)等对荧光材料进行了表征。XRD结果表明,所制备的样品为较好的单相。BaSi2N2O2∶Eu2+在395 nm和460 nm激发下均具有较高的发射强度,发射峰位于492 nm附近。当Eu2+的摩尔分数为4%时,可以获得最佳的样品发光强度。将荧光材料封装在紫外和蓝光芯片上制作了LED器件,两种器件均发射出强的蓝绿色荧光,色坐标分别为(0.092 0,0.428 2)和(0.112 9,0.223 0)。

La^3＋掺杂对BaSi2O2N2：Eu^2＋荧光粉发光性能的影响

研究了La3+掺杂对BaSi2O2N2∶Eu2+发光性能的影响。通过高温固相反应制备了纯相的Ba0.94-Si2O2N2∶0.06Eu2+荧光粉。在此基础上进行La3+的掺杂,并对少量La3+掺杂的LaxBa0.94-1.5xSi2O2N2∶0.06Eu2+荧光粉的结构和光学性能进行了研究。XRD图谱表明粉体在低掺杂时保持了基质BaSi2O2N2的晶格结构。通过共掺x=0.035的La3+可使荧光粉的发光效率提高到157%,原因是La3+部分取代Ba2+产生了阳离子缺陷,其可以吸收光源能量并将能量传递给Eu2+。最终这些能量通过Eu2+的4f65d→4f7跃迁以光辐射的形式释放出来。

Microwave Assisted Sintering and Photoluminescence Properties of BaaSi6OleNe：Eu^2＋ Green Phosphors

Eu^2＋-doped Ba3Si6012N2 green phosphors were prepared by microwave assisted sintering method at 1275℃ for 4 h, while the counterparts using conventional solid-state reaction method were synthesized at temperature higher than 1300℃ and for to 10 h. Microwave assisted sintering could reduce the activation energy and enhance the diffu- sion rate, thus greatly improved the sintering. Moreover, the influence of Si3N4 content on phase formation, morphol- ogy, absorption, and quantum efficiency, and photoluminescence properties of phosphors were studied. As a result, the Ba3Si6OI2N2：Eu^2＋ samples sintered by microwave assisted sintering method have a higher phase purity and photo- luminescence intensity under ultraviolet excitation as compared with samples sintered in the conventional tube furnace The proposed method is a potential preparation method for the oxynitride phosphors with strong photoluminescence and high phase purity.

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.

Influence of Molten Salt on Luminescent Intensity and Particle Size of Y_2O_3:Eu^(3+) Phosphor

The Y-Eu oxalate precursor was prepared with a homogeneous precipitation method. And the additives, Na2CO3, S, NaCl or their combination, were introduced into the precursor to prepare Y2O3 ：Eu^3＋ red phosphors at 1000 1300 ℃ for 2 h. The effect of molten salts on particle size and luminescent intensity was studied. The experimental results showed that the complex molten salt （Na：CO3 ＋ S ＋ NaCl） was conductive to enhance the luminescent intensity of Y2O3 ：Eu^3＋. The emission intensity of the phosphor prepared with these additives at 1300 ℃ was about 45% higher than that of the one prepared without molten salt, and about 11% higher than that of the corresponding commercial phosphor. Meanwhile, the particle size of Y2O3 ：Eu^3＋ phosphor was controlled effectively with the molten salt.

Synthesis and Photoluminescence of BaMgAl_(10)O_(17)∶Eu^(2+) Phosphor by Oxalate Co-precipitation Process

Single phase of Ba1-x MgAl10O17 ： x Eu^2＋ （0.02≤ x ≤ 0. 14） phosphors was first successfully prepared by coprecipitation in aqueous medium with a “reverse strike” method, using oxalic acid and ammonia together as precipitants. Completely crystallized phosphors were obtained at 1300 ℃, which is 300 ℃ lower than the temperature of solid-state reaction. Their photoluminescence was investigated under UV and VUV region, respectively. The emission spectra of Ba1-x MgAl10O17：xEu^2＋ samples excited by 254 or 147 nm showed a characteristic wide band with the peak centred at about 450 454 nm. Optimum emission intensity reached at x = 0.1 and then concentration quenching occurred. The synthesized phosphor shows 10% higher emission intensity than that prepared by solid-state reaction.

Vacuum ultraviolet excited photoluminescence properties of Gd_2O_2CO_3:Eu^(3+) phosphor

The Gd2O2CO3：Eu^3＋ with type-Ⅱ structure phosphor was successfully synthesized via flux method at 400 ℃ and their photoluminescence properties in vacuum ultraviolet （VUV） region were examined. The broad and strong excitation bands in the range of 153-205 nm owing to the CO3^2- host absorption and charge transfer （CT） of Gd^3＋-O2^- were observed for Gd2O2CO3：Eu^3＋. Under 172 nm excitation, Gd2O2CO3：Eu^3＋ exhibited strong red emission with good color purity, indicating Eu^3＋ ions located at low symmetry sites and the chromaticity coordination of luminescence for Gd2O2CO3：Eu^3＋ was （x=0.652, y=0.345）. The photoluminescence quenching concentration of Eu^3＋ excited by 172 nm for Gd2O2CO3：Eu^3＋ was about 5%. Gd2O2CO3：Eu^3＋ would be a potential VUV-excited red phosphor applied in mercury-free fluorescent lamps.

Y^(3+)掺杂对Sr_(1-x)Ca_xSi_2O_2N_2∶Eu^(2+)发光性能的影响

采用高温固相反应法制备了Sr_(1-x)Ca_xSi_2O_2N_2∶Eu^(2+)系列荧光粉,研究Y^(3+)离子掺入对荧光粉发光性能的影响。对于Sr Si_2O_2N_2∶Eu^(2+),Y^(3+)离子掺入主要起到稳定Eu^(2+)价态的作用,避免Eu^(2+)氧化为Eu^(3+),从而提高Sr Si_2O_2N_2∶Eu^(2+)的发光性能。对于Ca Sr Si_2O_2N_2∶Eu^(2+),Y^(3+)离子掺入除了稳定Eu^(2+)价态作用外,还能有效减小Eu^(2+)取代Ca^(2+)后晶格膨胀引起的应力,提高Eu^(2+)在晶格中的溶解度。Sr_(1-x)Ca_xSi_2O_2N_2∶Eu^(2+)(x=0,0.15,0.3,0.6,0.75,0.95)系列荧光粉中随着Ca含量的增加,共掺Y^(3+)离子对样品发光强度的提高程度也随之增加(20%~80%)。

通过SiO2涂层改善BaSi2O2N2∶Eu2+荧光粉的热性能（英文）

本文研究了SiO2涂层对BaSi2O2N2∶Eu^2+蓝绿色荧光粉发光性能和热性能的影响。采用溶胶-凝胶法制备了SiO2包覆的BaSi2O2N2∶Eu^2+蓝绿色荧光粉。实验结果表明,最佳镀膜量为6wt%,当镀膜量大于此值时,荧光粉亮度迅速降低。涂覆SiO2后,在150℃下BaSi2O2N2∶Eu^2+荧光粉的热猝灭性能提高了2.4%,在500℃热降解后荧光粉的发光性能提高了15%。SiO2涂层显著提高了BaSi2O2N2∶Eu^2+荧光粉的热稳定性。SiO2涂层的作用机理是在荧光粉表面和氧化气氛之间形成阻挡层,保护Eu^2+的发光中心在热加热过程中不被氧化。

Interaction of Rare Earth Ions in Sr2MgSi2O7：Eu^2＋,Dy^3＋ Material

To discuss the function of Eu and Dy and their interaction in Sr2 Mg Si2O7：Eu^2＋,Dy^3＋ long afterglow material,the Eu and Dy single doped and their co-doped Sr2 Mg Si2O7：Eu^2＋,Dy^3＋ were prepared.The samples were characterized by X-ray diffraction（XRD）,decay curves,photoluminescence（PL）,and thermoluminescence（TL）.The results indicate that Sr2 Mg Si2O7：Eu has afterglow properties,and the doping of Eu ion in Sr2 Mg Si2O7：Eu^2＋,Dy^3＋ can lower the depth of traps.Eu ion can not only serve as luminescence center,but also produce traps in the matrix,meanwhile,it also exerts certain influences on the traps produced by Dy in Sr2 Mg Si2O7：Eu^2＋,Dy^3＋.The Dy ion can not act as luminescence center but relates to the change of the traps in the Sr2 Mg Si2O7 matrix.

Ce3+,Eu2+共掺Ba3Si6O12N2荧光粉发光特性及能量传递研究（英文）

通过高温固相法制备了一系列Ce^3+/Eu^2+共掺杂的Ba3Si6O12N2,利用X射线衍射(XRD)研究了其晶体结构。研究表明,Ba3Si6O12N2∶Ce^3+,Eu^2+荧光粉在338nm光激发下可以发射525nm的绿光,且具有较大的半峰宽。研究还发现,单掺Ce^3+的发射光谱和单掺Eu^2+的发射光谱存在交叠,同时Ce^3+的5d1最低能级能量低于Eu^2+的4f65d1最低能级,这二者共同证实了可能存在Ce^3+到Eu^2+的能量转移现象。同时还研究了Ce^3+浓度对Ba(2.7-y)Si6O12N2∶0.3Eu^2+,yCe^3+(0≤y≤0.1)系列荧光粉发光强度和波长的影响。热猝灭性能研究表明,Ce^3+引入可显著影响体系的热猝灭性能。

常规与倒置A^2/O工艺处理猪场消化液比较研究

以高COD、高NH4+-N含量、低C/N的猪场厌氧消化液为研究对象,比较了常规A^2/O与倒置A^2/O工艺在碳源利用及脱氮除磷效果方面的差异。结果表明,在总HRT均设为124 h、消化液回流体积比和污泥回流体积比分别为300%和50%的相同条件下,倒置A^2/O对厌氧消化液中的COD、氮和磷的去除率比常规A^2/O分别提升了8.16、10.83、27.32百分点。倒置A^2/O稳定运行后出水COD和NH4^+-N、TP的质量浓度最低分别为228 mg/L和63、8 mg/L,达到GB 18596-2001的排放要求。倒置A^2/O将缺氧池前置而使得厌氧池与好氧池直接相连,有利于提高缺氧池对低C/N废水中碳源的利用率,提升系统反硝化脱氮能力;而且能够保证厌氧池的厌氧环境,增加好氧池的吸磷动力,从而有利于系统除磷效率的提高。

Preparation, electronic structure, and photoluminescent properties of Eu^(2+) activated BaSi_2O_5 powder phosphors for solid-state lighting

The green-emitting phosphor BaSi2O5 ：Eu^2＋ was synthesized by the conventional solid state reaction. Using the CASTEP code, BaSi2O5 is calculated to be an intermediate band gap semiconductor with an indirect energy gap of about 3.2 eV. As expected, the calculated optical band gap of BaSi2O5 is lower compared to the experimentally determined values. Eu^2＋-activated BaSi2O5 phosphor can be excited efficiently over a broad spectral range between 200 and 400 nm, and has an emission peak at 500 nm with a full width at half maximum of 95 nm. The study of concentration-dependent emission intensity shows the optimal concentration of the Eu^2＋ is 0.05 mol, and that concentration quenching occurs when the Eu^2＋ content is beyond the critical value. The external quantum efficiency of the optimized BaSi2O5 ：Eu^2＋ is 96. 1%, 70.2% and 62.1% under excitation at 315,350 and 365 nm, respectively. The superior optical properties of the sample show the potential as an ultraviolet converting green-emitting phosphor for white light emitting diodes.

Effect of fluxes on synthesis and luminescence properties of BaSi_2O_2N_2:Eu^(2+) oxynitride phosphors

Eu^2＋ activated BaSi2 O2 N2 oxynitride bluish-green phosphor was synthesized adopting conventional high-temperature solid-state reaction method, in which BaF2, Na2 CO3 and NH4 Cl were used as the fluxes.The phase formation, size distribution and microscopic morphology were characterized to investigate the influence of adding fluxes on photo luminescence properties. The results indicate that with the addition of BaF2 flux, the particle morphology becomes regular and size distribution narrows and the phase purity of BaSi2 O2 N2：Eu^2＋ phosphor can be improved effectively. The photoluminescence intensity of BaSi2 O2 N2：Eu^2＋ phosphor with BaF2 as flux gets enhanced obviously, which is much higher than that of Na2 CO3, NH4 Cl and without flux. The optimum content of BaF2 flux is 4 wt%, and the maximum photoluminescence intensity of the BaSi2 O2 N2：Eu^2＋ phosphor prepared with BaF2 flux rises to 141%,meanwhile, the phosphors with BaF2 flux exhibits low thermal quenching. The results indicate that the BaSi2 O2 N2：Eu^2＋ is sort of promising bluish-green phosphor for application in full-spectra LED.

Preparation and characterization of flower-like SrAl_2O_4:Eu^(2+),Dy^(3+) phosphors by sol-gel process

A flower-like Eu^2＋ and Dy^3＋ co-doped SrAl2O4 long-lasting phosphorescent （LLP） phosphor was synthesized via the inorganic- salt-based sol-gel method. The crystal structure, morphology and optical properties of the composite were characterized. X-ray diffraction diffusion （XRD） data and DSC-TG curves of the phosphor revealed that the SrAl2O4 crystallites have been formed after the precursor was calcined at 900 ℃ and to be single-phase SrA1204 at 1100 ℃. The SEM photographs indicated that the sample exhibited a universal flower-like morphology with crystallite size of about l-2μm. After being irradiated with ultraviolet （UV） light, the flower-like phosphor emitted long-lasting green phosphorescence with an excitation peak at 365 nm and emission peak at 500 nm which was ascribed to the characteristic 5d-4f transition of Eu^2＋. Both the PL spectra and the luminance decay curve revealed that this phosphor exhibited efficient luminescence and long lasting properties.

A Novel Synthesis of Alkaline Earth Silicate Phosphor Sr3MgSi2O8： Eu^2＋, Dy^3＋

A novel method for synthesizing long afterglow silicate phosphor Sr3MgSi2O8：Eu^2＋,Dy^3＋using TEOS and inorganic powders as reactants was reported. Acetic acid as a catalyzer controlled the hydrolysis of TEOS by adjusting pH value of the system. The morphologies of precursor were characterized by transmission electron microscope （TEM）. The structure and optical properties of the phosphor powders were systematically investigated by means of X-ray diffraction and spectrofluorometry. TEM images have reflected the core-shell structure and quasi-spherical morphology of the precursor particles. It was found that the single-phase Sr3MgSi2O8 crystalline structures were obtained at 1050 and 1250 ℃ for the samples prepared with the nano-coating method and the solid state reaction, respectively. The emission intensities of the phosphors prepared by the present method were higher than those by the conventional process. Also, the afterglow characteristic was better than that prepared by solid-state reaction in the comparable condition.

The thermal and irradiation degradation mechanisms of Eu^(2+),Mn^(2+) co-doped BaMgAl_(10)O_(17) phosphor

The mechanisms of thermal,ultraviolet and vacuum ultraviolet radiation degradation behaviors of the Eu2+,Mn2+ co-doped BaMgAl10O17 phosphors were investigated comparatively.The result indicated that the Mn2+ ions which replaced the Mg2+ sites in the sample were stable and negligibly influenced by treatments.The oxidation and migration of Eu2+ ions primarily caused the thermal degradation of the sample.The vacuum ultraviolet radiation degradation was primarily because of the migration of Eu2+.The ultraviolet radiation increased traps which trended the Eu2+r to be in a metastable state,leading to the ultraviolet radiation degradation of the sample.The vacuum ultraviolet excited luminous loss of samples after ultraviolet radiation partly originated from the interruption of energy transfer from the host to activators by traps.

Effect of sintering temperature on luminescence properties of borosilicate matrix blue–green emitting color conversion glass ceramics

The color conversion glass ceramics which were made of borosilicate matrix co-doped(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors were prepared by two-step method in co-sintering. The change in luminescence properties and the drift of chromaticity coordinates(CIE) of the(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors and the color conversion glass ceramics were studied in the sintering temperature range from 600℃ to 800℃. The luminous intensity and internal quantum yield(QY) of the blue-green phosphors and glass ceramics decreased with the sintering temperature increasing. When the sintering temperature increased beyond 750℃, the phosphors and the color conversion glass ceramics almost had no peak in photoluminescence(PL) and excitation(PLE) spectra. The results showed that the blue-green phosphors had poor thermal stability at higher temperature. The lattice structure of the phosphors was destroyed by the glass matrix and the Ce^3+ in the phosphors was oxidized to Ce^4+, which further caused a decrease in luminescent properties of the color conversion glass ceramics.

巴戟天中环烯醚萜苷和蒽醌在电喷雾离子源负离子模式下的质谱裂解行为

利用电喷雾-四极杆-飞行时间串联质谱(ESI-Q-TOF MS/MS)技术,在负离子模式下,探讨巴戟天中4种环烯醚萜苷和2种蒽醌成分的质谱裂解途径。通过[M-H]-获得化合物的相对分子质量信息,进一步对[M-H]-进行碰撞诱导解离,获得相应化合物的裂解途径。结果表明,环烯醚萜苷主要的裂解途径是首先脱去母环上的功能基团,如中性丢失H_2O、CO_2、CH_3COOH和糖单元等部分;其次是二氢吡喃环和糖环的断裂,m/z113、101为环烯醚萜苷母环断裂的特征碎片离子。蒽醌类化合物的裂解行为是连续失去CO,也可以失去CO_2。这些质谱裂解行为的研究有助于环烯醚萜苷和蒽醌类化合物的结构解析,也可为其他同类化合物的鉴定提供依据。

LED用BSON蓝绿粉的合成和应用研究

本文采用高温固相法合成BaSi_2O_2N_2∶Eu^(2+)蓝绿色荧光粉,探索了温度和时间对荧光粉性能的影响,同时通过添加助熔剂有效提升了荧光粉性能。BaSi_2O_2N_2∶Eu^(2+)荧光粉搭配YAG∶Ce^(3+)和CaAlSiN_3∶Eu^(2+)荧光粉,可以达到LED正白光段显色指数R_1~R_(15)大于90的全光谱目的。该方案解决了之前LED光源制作高显色方案中显色指数R_(12)偏低的现象,补充了白光LED缺失深蓝色的部分,对LED的推广有着重要的意义。