场发射(FED)用荧光粉的研制与改性

场发射平板显示器（Field Emission Displays, FED）是一种新发展起来的平板显示器，由于其在亮度、视角、响应时间、工作温度范围、能耗等方面具有优良的特性，成为近年新型显示器研究的热点之一。为实现高效的FED红、绿、蓝全色显示，荧光粉在其中起着十分重要的作用。制备性能优良的场发射用彩色荧光粉是决定将来FED技术成功与否的关键因素之一。 本论文研究的内容包括场发射(FED)用荧光粉的研制和改性工作。在场发射(FED)用荧光粉研制方面，采用溶胶-凝胶方法，制备了一系列新型场发射(FED)用荧光粉，包括稀土离子激活的镓酸镧 [(LaGaO3: Re3+ (Re = Eu, Tb, Dy, Tm, Sm)]体系、铟酸钙[(CaIn2O4: Re3+ (Re = Eu, Pr, Tb, Dy,)]体系、铟酸锶[(SrIn2O4: Re3+ (Re = Pr, Tb, Dy)]体系、镓酸镥[Lu3Ga5O12:Re3+ (Re = Eu, Tb，Pr)]体系，并研究了Pr, Sm, Eu, Tb, Dy, Tm等稀土离子在这些基质中的光致发光、低压阴极射线发光性质和能量传递等性质。在荧光粉的改性方面，采用喷雾热解法制备了Sr2CeO4球形场发射用荧光粉，研究了喷雾前驱体溶液中，聚乙二醇浓度、金属离子浓度、烧结温度对形貌及发光性能的影响；采用溶胶－凝胶方法成功将SiO2表明包覆一层CaTiO3:Pr3+, Y3Al5O12:Ce3+/Tb3+荧光粉，得到单分散，球形形貌，分布均匀，具有核/壳结构的球形荧光粉；另外研究了不同的制备方法对Ga2O3:Dy3+荧光粉的发光性能的影响。所得样品用XRD、FTIR、SEM、TEM、漫反射光谱、光致发光(PL)光谱、荧光寿命曲线、低压阴极射线(CL)光谱等进行表征。 在紫外光激发下，稀土离子激活的镓酸镧彩色荧光粉有基质(LaGaO3)的发射和稀土离子(Eu3+, Tb3+, Dy3+, Tm3+, Sm3+)的特征发射，研究表明在基质和稀土离子之间存在能量传递，其能量传递效率因离子而异。在阴极射线激发下，样品仅有稀土离子(Eu3+, Tb3+, Dy3+, Tm3+, Sm3+)的特征发射。如：LaGaO3: Eu3+发红光，LaGaO3: Dy3+发白光，LaGaO3: Tm3+发蓝光，LaGaO3: Sm3+发黄光，LaGaO3: Sm3+,Tb3+发白光。LaGaO3: Tb3+的发光颜色可通过不同Tb3+的掺杂浓度从蓝光到绿光进行调控。在相同的激发条件下，所制备的蓝光发射的LaGaO3: Tb3+和LaGaO3: Tm3+荧光粉与商业FED用蓝粉(Y2SiO5: Ce3+，日亚化学工业株式会社，NP-1047)相比具有更好的色纯度和更高的发光效率；所制备的黄光发射的LaGaO3: Sm3+荧光粉与商业低压黄色荧光粉((Zn,Cd)S: Ag，日亚化学工业株式会社，NP-1020)相比，色纯度接近，但具有更高的发光效率。并首次实现了单一基质中白光发射(LaGaO3: Sm3+,Tb3+), 所制备的稀土离子激活的镓酸镧彩色荧光粉[(LaGaO3: Re3+ (Re = Eu, Tb, Dy, Tm, Sm )]在场发射器件有潜在的应用。 在稀土离子掺杂的Sr/CaIn2O4荧光粉体系中，在基质Sr/CaIn2O4和掺杂离子Pr3+/Tb3+/Dy3+存在高效能量传递。基质Sr/CaIn2O4吸收能量向激活离子Pr3+/ Tb3+/Dy3+传递，发射为稀土离子Pr3+/Tb3+/Dy3+的特征发射，发光强度、荧光寿命等符合应用要求，在低压电子束激发下，Sr/CaIn2O4: Pr3+/Tb3+/Dy3+荧光粉为稀土离子的特征发射，其低压阴极射线发光(CL)光谱与光致发光(PL)发射光谱一致，CL强度随激发电压，电流密度增加而增强。 对于CaIn2O4:Eu3+荧光粉，进一步研究表明CaIn2O4:Eu3+荧光粉的光致发光和阴极射线发光颜色可以通过掺杂不同浓度的Eu3+从白光，黄光，到红光进行调控。低浓度掺杂发白光，高浓度掺杂发红光，适当的浓度发黄光。 在Lu3Ga5O12:Re3+ (Re = Eu, Tb，Pr)荧光粉体系中，在紫外（UV）和低压阴极射线激发下，所制备的荧光粉Lu3Ga5O12: Eu3+, Lu3Ga5O12: Pr3+为稀土离子Eu3+, Pr3+的特征发射，分别发黄光和绿光。Lu3Ga5O12:Tb3+的发光颜色因Tb3+掺杂浓度不同而不同，低浓度掺杂发蓝光，高浓度发绿光。 Sr2CeO4荧光粉在UV及低压阴极射线激发下发出强烈蓝光，源于配体到金属离子电荷迁移带跃迁(Ce4+-O2-)。其阴极射线发光强度与电压及灯丝电流呈良好的线性关系。 采用溶胶－凝胶方法的核壳结构的SiO2@CaTiO3:Pr3+和SiO2@Y3Al5O12: Ce3+/Tb3+荧光粉, FESEM和TEM结果表明这种核壳结构的发光材料表面致密，厚度均匀，保持了单分散SiO2微球的形貌特征。在UV及低压阴极射线激发下，SiO2@CaTiO3:Pr3+呈强红色发射，源于Pr3+ 的1D2—3H4 (612 nm)跃迁；SiO2@Y3Al5O12:Ce3+和SiO2@Y3Al5O12:Tb3+ 分别发黄绿光和绿光，源于Ce3+的5d-4f和Tb3+的5D4-7FJ (J = 6, 5, 4, 3)跃迁。PL强度可以通过包覆次数调控，CL强度随激发电压及灯丝电流增加而增强。 在Ga2O3:Dy3+荧光粉体系中，采用了溶胶-凝胶，氨水共沉淀，和高温固相法制备了Ga2O3:Dy3+荧光粉并比较了他们的结晶行为，形貌，光致发光和低压阴极射线发光性能。溶胶-凝胶法制备由于原料在分子层次上混合，可以得到纯相，氨水共沉淀和高温固相法原料不如溶胶凝胶法混合均匀，很难得到纯相。溶胶-凝胶和氨水共沉淀所得荧光粉为纳米级别大小，分别呈球形和玉米棒形状；高温固相法微米级别且呈不规则形状。Ga2O3向Dy3+传递能量效率依次按溶胶-凝胶，氨水共沉淀，和高温固相法逐渐降低。在紫外光激发下，分别发白光，蓝白光，蓝光。其低压阴极射线发光与光致发光类似。相比之下，溶胶-凝胶法制备Ga2O3:Dy3+荧光粉比氨水共沉淀和高温固相法制备要好。

SEBS、POE与异氰酸酯的接枝反应及其对PA6、PBT的增韧研究

本工作采用熔融反应接枝的方法将(3-异氰酸酯基-4-甲基)苯氨基甲酸-2-丙烯酯(TAI)引入到聚苯乙烯-b-聚(乙烯-co-丁烯)-b-聚苯乙烯三嵌段共聚物(SEBS)上，以实现SEBS的功能化。红外光谱表明TAI已经成功接枝到SEBS上。GPC测试表明接枝后SEBS具有高的分子量与宽的分子量分布。DMA分析证明，接枝后聚(乙烯-co-丁烯) (PEB)段的玻璃化转变提高。对未参与接枝的单体的分析表明，单体TAI是个不容易自聚的单体，并对接枝过程的机理进行了研究。 为了提高TAI的存储稳定性和解决反应过程中的毒性大的问题，采用己内酰胺为封端剂对TAI中的异氰酸酯进行了封端。红外光谱和核磁共振结果表明，己内酰胺封端的TAI（BTAI）中含有双键和封闭型异氰酸酯结构，不存在着活泼的异氰酸酯。红外光谱结果表明，在高温下BTAI可以重新产生活泼的异氰酸酯基团。DSC与TG/DTA研究证明，BTAI的初始解离温度大约为135 C。采用熔融反应接枝的方法将BTAI接枝到SEBS和乙烯-辛烯共聚物（POE）分子上。研究表明，接枝率随着单体含量或引发剂含量的增加而增加。接枝以后的SEBS与POE的剪切变稀行为都比未接枝的SEBS与POE要明显。 利用BTAI功能化的SEBS和POE两种弹性体，通过熔融反应共混方法制备了PA6合金。两种弹性体与PA6共混物的红外光谱和流变行为的研究表明，在反应共混中形成了新的接枝共聚物。共混物的脆断面的场发射扫描电镜照片表明，共混物形成一种海-岛结构，而反应共混物的具有更均匀的粒子分散性，更小的粒子尺寸。PA6/SEBS-g-BTAI共混的透射电镜照片说明，共混物中形成了一种以PS为核-PEB为壳的核壳结构。与相应的物理共混物相比，通过反应共混制备的PA6合金（PA6/SEBS-g-BTAI合金和PA6/POE-g-BTAI合金）的拉伸强度、杨氏模量得到了提高。两种反应共混物的缺口冲击强度得到了非常明显的提高，合金材料的缺口冲击强度可以达到1000 J/m 以上。共混物中弹性体对PA6的结晶起到了成核的作用，结晶温度提高。形成的共聚物阻碍了PA6的分子链的运动，使得PA6的结晶温度下降。 本工作还利用上述制备的POE-g-BTAI和SEBS-g-BTAI两种功能化的弹性体与聚对苯二甲酸丁二醇酯（PBT）进行共混。研究表明，在反应共混过程中PBT中的反应基团与释放出的异氰酸酯发生反应，生成了新的共聚物。通过共混物的脆断面的FESEM图片可以看到，POE与PBT的共混物中，POE以球状粒子分散在PBT中，并且反应共混物的粒子分散均匀，粒子尺寸变小。与POE/PBT共混不同的是，在PBT与SEBS共混过程中，二者形成了交错结构，而反应共混在较低含量就形成了交错结构。POE与PBT反应共混物的缺口冲击强度得到了很大的提高，冲击强度可以达到1100 J/m以上，而PBT与SEBS的反应共混物的冲击强度改变不大。相对于物理共混物，两种弹性体与PBT的反应共混物的拉伸强度与拉伸模量都得到了提高。弹性体的加入提高了PBT的结晶温度，反应共混物的结晶温度低于物理共混物的结晶温度，说明弹性体的加入起到了PBT的成核剂的作用，生成的共聚物亦阻碍了PBT的分子链的移动。 关键词：聚苯乙烯-b-聚(乙烯-co-丁烯)-b-聚苯乙烯三嵌段共聚物；乙烯-辛烯共聚物；封闭型异氰酸酯；反应加工；聚酰胺6；聚对苯二甲酸丁二醇酯

纳米／微米结构氧化物材料的水热合成、形貌与发光性质研究

采用水热法结合后续热处理制备了一系列纯的和稀土离子（Eu3＋，Dy3＋）掺杂的黔具有纳米／微米结构的无机氧化物材料，包括YB03、姚03、Ga203和硅基MCM一攀41介孔分子筛体系。研究了这些体系的水热产物的晶体形貌、结构以及它们的生乖～一＿长机理，并通过进一步热处理得到了保持水热产物纳米／微米结构形貌的发光材料，报道了以上各个体系材料的光致发光性能。一把姚03和Eu203粉末直接加入H3Bo3水溶液中，调节pH一1一4，在180一270夸＿少℃水热处理得到了具有vaterite结构的YBo3：Eu3＋晶体。xRD和FEsEM结果证明一扭03：E矿"晶体是由厚度小于50nm的纳米晶片构成的花状和猴头菇状的微米级晶丫体。水热温度提高时纳米晶片的厚度没有增加，形貌也不变，但是结晶度和发光一强度有所提高。pH值对纳米晶片之间的距离、角度和晶片数量有影响。pH低时，纳米晶片更多且包裹得更紧，形成了猴头菇状；而pH高时，晶片分得更开一些呈花朵状。这与pH值低时结晶成核较快较多有关。YB03：E矿＋水热和固相法样品在24Onm激发下的发光谱峰位相同。但水热样品比固相法样品具有较高的红橙比［Eu3＋：I（，D。一7F2）／I（SD。一7FI）］，增加了12一37％。在24oC下制备的花03：Eu3＋水热样品具有最大的结晶度和发光强度。报道了三种晶形调节剂对水热晶体形貌的影响结果。硝酸钻水溶液用氨水调节至pH一8一n，200oC下水热处理24小时，产物经xRD确定是单斜晶系的碱式硝酸盐叽O（0H）9困03）。FEsEM观察发现产物是一种具有几＿三叶形截面的棱柱。改变合成条件可以调节三叶形棱柱的尺寸。增加氨水量时，PH从8调到n后，棱柱直径可从微米级调节到亚微米级，即从3一5林m左右下降到200一300纳米，同时长径比也有所增加，从pH一8的5增加到pH＝n的10。调节机制可解释为较高的pH条件下结晶成核作用进行较快，形成了更多的晶核。三叶形棱柱的生长机理是、O（OH）9困03）的晶核依靠内在的趋势长成棒状纳米粒子；并通过一种直接的聚集生长，这些起始的纳米棒沿着它们横截面的径向方向快速自堆积成一种Y型结构的棒束；然后沿着棱柱轴向和平行于棱柱叶片方向的晶面同时优先生长，而垂直于叶片方向上的晶面生长得相对缓慢，导致三叶形棱I、－纳米／微米结构氧化物材料的水热合成、形貌与发光性质研究柱的形成。、经过高温相转变得到了姚03三叶形棱柱。采用同样方法可以制得姚03：E矿＋的三叶形棱柱发光粉，其光谱与固相法样品的一致。将Gacl3一HZO一NaOH体系在pH＝6一8时于180℃下水热处理得到了正交晶系的Gao0H晶体，其形貌分别是宽度在200一30Onm之间长径比约1：7的四方棱柱（pH＝6）和长径比约1：3纺锤状的纳米棒束（pH＝8）。使用HZO／DEG混合溶剂可以增加棱柱的长径比，1：Ivol时增加到1：15；1：Zvol时获得的是长达几十微米的四方棱柱纳米线6Go0OH纳米棒是从最初的胶状沉淀中成核后沿着c轴优先生长而成的。pH值的高低可导致Ga0OH晶体从四方棱柱到纳米棒束的不同形貌。DEG的存在对晶体的生长可能有两点作用：一是抑制晶核形成；二是降低晶体沿着横截面晶面的生长速度。经过高温锻烧的产物是保持着前驱体形貌的p一GaZO3晶体。254nm激发下p一GaZO3纳米棒的发射谱是从300nm到600nln的宽峰，最大值在455nln。发光的平均寿命是64ns。其蓝光发射起源于氧空位给体提供的电子和来自受体嫁空位或者嫁氧空位对的空穴之间的复合。采用相似方法制备了p一GaZO3：Dy纳米棒束，并与固相法样品对比了光谱性质的异同。将三种5102基材料：MCM一41型分子筛（直接分子筛CMS和萃取分子筛EMS）、无规颗粒（ASP）和干凝胶（SG）进行从室温到1000℃的不同温度不同时间热处理。254nm激发下，MCM一41没有发光现象。而ASP和SG系列样品随着热处理温度不同而显示不同的PL。说明ASP和SG与MCM一41有着不同的发光机理。排除了ASP和SG样品的发光中心是来自5102网络本身的结构缺陷，认为是其中所含有机物在热处理中产生的碳杂质引起。结果也表明MCM41中模板剂在热处理的碳化产物并没有引起MCM一41的PL。在365nm激发下，MCM一41与ASP、SG的PL现象大致相同。表明所有系列的样品的发光机理相同。CMS和EMS两个系列在300℃以上处理的样品的PL相似，说明模板剂的存在及其碳化并没有影响MCM一41的PL。所有系列样品在365nm激发下的PL认为是起源于5102网络中与氧相关的结构缺陷三Si一0．，而不是碳掺杂作用引起的。

改进的SILAR法制备ZnO薄膜及其表征

A modified solution method, successive ionic layer adsorption and reaction(SILAR), was applied to prepare transparent zinc oxide(ZnO) film on glass substrate at (125±5) ℃ in mixed ion precursor solution. The surface morphology and crystallizations of films were analyzed by field emission scanning microscopy(FESEM) and X-ray diffraction(XRD), respectively. The optical properties of the films were studied by ultraviolet visible(UV-Vis)spectroscopy. The results show that the obtained samples are polycrystallin...中文文摘：采用一种改进的液相成膜技术——连续离子层吸附与反应(SILAR)法,用锌氨络离子[Zn(NH3)4]2+溶液作为独立的前驱体溶液,以载玻片为衬底,在(125±5)℃的温度下沉积出致密、透明的ZnO薄膜。分别用冷场发射型扫描电镜(FESEM)和X射线衍射(XRD)分析了薄膜样品的表面形貌和结晶状态,用紫外-可见分光光度计(UV-Vis spectroscopy)研究了薄膜样品的发光性能。结果表明:获得样品为六角纤锌矿结构的多晶薄膜材料沿[002]方向择优生长;样品表面均匀、致密,厚度约为550nm;在可见光波段具有高的透射率(>80%)。

改进的SILAR法制备ZnO薄膜及其表征

采用一种改进的液相成膜技术——连续离子层吸附与反应(SILAR)法,用锌氨络离子[Zn(NH3)4]2+溶液作为独立的前驱体溶液,以载玻片为衬底,在(125±5)℃的温度下沉积出致密、透明的ZnO薄膜。分别用冷场发射型扫描电镜(FESEM)和X射线衍射(XRD)分析了薄膜样品的表面形貌和结晶状态,用紫外-可见分光光度计(UV-Vis spectroscopy)研究了薄膜样品的发光性能。结果表明:获得样品为六角纤锌矿结构的多晶薄膜材料沿[002]方向择优生长;样品表面均匀、致密,厚度约为550nm;在可见光波段具有高的透射率(>80%)。

重离子径迹模板法电化学制备聚吡咯纳米线

采用蚀刻的聚碳酸酯(PC)离子径迹膜为模板,结合电化学沉积技术,制备出了直径为100~320 nm、长度从几μm到30μm的聚吡咯纳米线。利用场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)对纳米线的形貌进行了表征。结果表明,所制备出的聚吡咯纳米线均呈圆柱形,且表面光滑、粗细一致。聚吡咯纳米线的紫外-可见(UV-Vis)光谱分析表明,随着聚吡咯纳米线直径增加,聚吡咯纳米线吸收峰展宽,且峰位向长波方向移动。

Modification of ZnO films under high energy Xe-ion irradiations

ZnO films were deposited on (100) Si substrate by radio frequency magnetron sputtering. These films were irradiated at room temperature with 308 MeV Xe-ions to a fluence of 1.0 x 10(12), 1.0 x 10(13) or 1.0 x 10(14) Xe/cm(2). Then the samples were investigated using RBS, XRD, FESEM and PL analyses. The obtained experimental results showed that the deposited ZnO films were highly c-axis orientated and of high purity, 308 MeV Xe-ion irradiations could not change the c-axis oriented. The topography and PL properties of the ZnO films varied with increasing the Xe-ion irradiation fluence. For 1.0 x 10(13) or 1.0 x 10(14) Xe/cm(2) irradiated samples, surface cracks were observed. Furthermore, it was found that the 1.0 x 10(14) Xe/cm(2) irradiated sample exhibiting the strongest PL ability. The modification of structure and PL properties induced by 308 MeV Xe-ion irradiations were briefly discussed. (C) 2008 Elsevier B.V. All rights reserved.

Electrochemical polymerization and characterization of polypyrrole nanowires and nanotubules

Polypyrrole nanostructure arrays, including simultaneously large quantities of nanowires and small quantities of partially filled nanotubules have been electrochemically synthesized in home-made etched ion-track polycarbonate (PC) templates. Diameter of the prepared nanostructures varies from 45 to 320 nm with their lengths up to 30 microns. Morphological studies of these nanostructures were performed by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. While optical absorption properties were studied by ultraviolet-visible-near infrared spectrophotometry (UV-vis-NIR). It has been observed that the absorption maximum of polypyrrole shifts to the longer wavelength side as the diameter of these nanostructures (nanowires and nanotubules) increases. (C) 2010 Elsevier B.V. All rights reserved.

Controllable synthesis of metal hydroxide and oxide nanostructures by ionic liquids assisted electrochemical corrosion method

Cu(OH)(2) nanowires have been synthesized by anodic oxidation of copper through a simple electrolysis process employing ionic liquid as an electrolyte. Controlling the electrochemical conditions can qualitatively modulate the lengths, amounts, and shapes of Cu(OH)(2) nanostructures. A rational mechanism based on coordination self-assembly and oriented attachment is proposed for the selective formation of the polycrystalline Cu(OH)(2) nanowires. In addition, the FeOOH nanoribbons, Ni(OH)(2) nanosheets, and ZnO nanospheres were also synthesized by this route, indicative of the universality of the electrochemical route presented herein. The morphologies and structures of the synthesized nanostructures have been characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), powder X-ray diffraction (XRD). Fourier transform infrared spectra (FT-IR), and thermogravimetric (TG). (C) 2007 Elsevier Masson SAS. All rights reserved

Structure and electrochemical characteristics of melted composite Ti0.10Zr0.15V0.35Cr0.10Ni0.30-LaNi5 hydrogen storage alloys

The structure and electrochemical characteristics of melted composite Ti0.10Zr0.15V0.35Cr0.10Ni0.30+x% LaNi5 (x=0, 1, 5 and 10) hydrogen storage alloys have been investigated systematically. XRD shows that the matrix phase structure of V-based solid solution phase with a BCC structure and C14 Laves phase with hexagonal structure is not changed after adding LaNi5 alloy. However, the amount of the secondary phase increases with increasing LaNi5 content. Field emission scanning electron microscopy-energy dispersive spectroscopy (FESEM-EDS) shows that the C14 Laves phase contains more Zr and the white lard phase has a composition close to (Zr, Ti)(V, Cr, Ni, La)(2).

Microemulsion-mediated solvothermal synthesis and photoluminescent property of 3D flowerlike MnWO4 micro/nanocomposite structure

Novel three-dimensional (3D) flowerlike MnWO4 micro/nanocomposite structure has been successfully synthesized for the first time. The synthesized products were systematically studied by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) and photoluminescence (PL) spectra. It is found that both reaction time and temperature have significant effects on the morphology of the products.

Preparation and characterization of polyimide/Al2O3 hybrid films by sol-gel process

A sol-gel process has been developed to prepare polyimide (PI)/Al2O3 hybrid films with different contents of Al2O3 based on pyromellitic dianhydride (PMDA) and 4,4'-oxydianiline (ODA) as monomers. FESEM and TEM images indicated that Al2O3 particles are relatively well dispersed in the polyimide matrix after ultrasonic treatment of the sol from aluminum isopropoxide and thermal imidization of the gel film. The dimensional stability, thermal stability, mechanical properties of hybrid PI films were improved obviously by an addition of adequate Al2O3 content, whereas, dielectric property and the elongation at break decreased with the increase of Al2O3 content. Surprisingly, the corona-resistance property of hybrid film was improved greatly with increasing Al2O3 content within certain range as compared with pure PI film.

Fabrication of Superhydrophobic Cellulose-Based Materials through a Solution-Immersion Process

An industrial waterproof reagent [(potassium methyl siliconate) (PMS)] was used for fabricating a superhydrophobic surface on a cellulose-based material (cotton fabric or paper) through a solution-immersion method. This method involves a hydrogen bond assembly and a polycondensation process. The silanol, which was formed by a reaction of PMS aqueous solution with CO2, Was assembled on the cellulose molecule surface via hydrogen bond interactions. The polymethylsilsesquioxane coatings were prepared by a polycondensation reaction of the hydroxyl between cellulose and silatiol. The superhydrophobic cellulose materials were characterized by FTIR spectroscopy, thermogravimetry, and surface analysis (XPS, FESEM, AFM, and contact angle measurements).

Bluish-white emission from radical carbonyl impurities in amorphous Al2O3 prepared via the Pechini-type sol-gel process

Many efforts have been devoted to exploring novel luminescent materials that do not contain expensive or toxic elements, or do not need mercury vapor plasma as the excitation source. In this paper, amorphous Al2O3 powder samples were prepared via the Pechini-type sol-gel process. The resulting samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), photoluminescence (PL) excitation and emission spectra, kinetic decay, and electron paramagnetic resonance (EPR).

Polyol-Mediated Synthesis of PbS Crystals: Shape Evolution and Growth Mechanism

An interesting shape evolution of. PbS crystals, that is, from cubes to (truncated) octahedra and finally to stable star-shaped multipods with six arms along the < 100 > directions is first realized via a facile polyol-mediated reaction between lead acetate and sulfur powder in the absence of surfactants. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) techniques were employed to characterize the samples. We elucidate the important parameters (including reaction temperature and sulfur sources) responsible for the shape-controlled synthesis of PbS crystals.