稀土/高分子杂化发光材料的研究

用SiO2为无机组份和以与SiO2具有相似折射率和优良力学性能的丙烯酸类如甲基丙烯酸甲酯（MMA）和甲基丙烯酸羟乙酯（HEMA），在交联剂3－（三甲氧基硅）丙基甲基丙烯酸酯（MSMA）存在下，快速制备了两种杂化基质材料SiO2/P(MMA-MSMA)和SiO2/P(HEMA-MSMA)。分别以盐酸和六次甲基四胺作为酸性催化剂和碱性催化剂，建立了快速制备透明凝胶的两步溶胶－凝胶法，大大缩短了溶胶的成胶时间，所得杂化材料具有良好的光学透明性，利用此方法制备了掺杂稀土配合物的多种发光杂化材料。采用组装的方法，得到了稀土配合物与层次化合物α－磷酸氢锆（α－ZrP)及中孔分子筛材料MCM－41的组装体，并对所制备的杂化材料进行了表征。另外，将稀土配合物通过共价键嫁接于无机SiO2基质中，得到了含有稀土配合物的分子杂化材料。     

PMMA/凝胶玻璃复合材料作为非线性有机分子掺杂基质的研究

对分散红1（DR1）掺杂聚甲基丙烯酸甲酯（PMMA）／凝胶玻璃复合材料的光学二阶非线笥及其热稳定性进行了研究。结果表明,PMMA／凝胶玻璃作为一种有机／无机复合材料,是介于胶玻璃和PMMA之间的一种非线性有机分子掺杂基质。随复合材料中凝胶玻璃含量增多,所制备的非线性材料的热稳定性能变好。对非线性和热稳定性的折衷考虑,获得了制备光学二阶非线笥基质材料先体PMMA和正硅酸乙酯（TEOS）的最佳混合比例。     

PPV衍生物的激发态动力学特性研究

利用共振飞秒光学克尔效应研究了C10－PPV溶液的非线性光学响应。实验结果表明，在共振激发条件下，C10－PPV挑学克尔效应信号表现为快速上升和随后的驰豫过程，其驰豫过程由两部分组成，一个200fs的快过程和一个400ps的慢过程。通过比较C10－PPV和掺杂C60后的C10－PPV荧光光谱，400ps的慢过程可归属为聚合物链内单重态激子在不同共轭段间的迁移过程。     

各种烷氧基取代聚对苯乙炔的合成和发光性能研究

利用脱氯缩合聚合法合成了聚（2－甲氧基－5－丁氧基）对苯乙炔（PMOBOPV），聚（2－甲氧基－5－辛氧基）对苯乙炔（PMOCOPV）和聚（2－丁氧基－5－丁氧基）对苯乙炔（PDBOPV），聚（2－辛氧基－5－辛氧基）对苯乙炔（PD－COPV）4种发光材料。对反应体系的浓度，酸碱度，反应温度及时间等工艺条件和路线进行了细致的研究。结果表明：反应物的纯度，含量对合成产物的产率和性能有较大的影响；碱性是影响脱氯缩合反应的关键因素，而反应温度和时间对缩合反应影响则相对较小，在一定温度下当反应时间达到一定阶段后其转化率基本不变，对合成材料的化学结构，物理性能和发光特性进行了表征和检测。结果显示：非对称烷氧基取代PPV具有良好的溶解性，成膜性和稳定性；而对称性烷氧基取代PPV的溶解性和成膜性相对较差。以PMOBOPV为发光材料，采用旋涂工艺制作出单层和双层发光器件，并对器件的电致和光致发光性能进行了研究。     

Cl-离子修饰Ce3+掺杂SiO2材料发光峰的蓝移

采用溶胶凝胶技术通过添加Ce(NO3)3制备了掺杂Ce3 离子的纳米SiO2材料,进行了不同温度的氯化处理。采用电子能谱、吸收光谱以及荧光光谱对Cl-离子修饰Ce3 掺杂SiO2材料的成分及光学性能进行分析、测试,研究Cl-离子修饰对掺杂SiO2材料中Ce3 离子光学性能的影响。测试结果表明,经过氯化处理不仅可以明显提高Ce3 离子掺杂SiO2材料的发光强度,还可以使发光和激发波长产生明显的变化,发光波长由445 nm蓝移至390 nm,激发波长由326 nm蓝移至290 nm左右。这种转化具有可逆性,将经氯化处理的样品重新在空气中处理后,发光强度减弱,发光和激发波长也恢复到氯化处理前的位置。     

若丹明B掺杂的SiO2凝胶的荧光光谱研究

以正硅酸乙酯（TEOS）和有机染料若丹明B（Rhodamine B)为原料，彩溶胶－凝胶方法（the sol-gel method)制备了若丹明B掺杂的SiO2凝胶，研究了SiO2凝胶的荧光光谱。报道了若丹明B在SiO2凝胶中的荧光光谱比在水中的荧光光谱发生红移，尤其在制备过程中的不同阶段，若丹明B掺杂SiO2凝胶的荧光光谱的峰位发生的一系列变化，从而得到了若丹明B在水中及若丹明B在SiO2凝胶制备过程之中，直至SiO2凝胶制备完毕的荧光光谱发生变化的全过程。还报道了在反应中的磁力搅抖阶段，采用回流过程和不采用回流过程两种方法时，对所得若丹明B掺杂SiO2凝胶的荧光光谱的影响。     

烷氧基取代聚对苯乙炔三阶非线性光学性能

通过双醚化反应、氯甲基化反应以及在强碱性条件下进行的脱氯化氢反应制备聚（2-甲氧基-5-丁氧基）对苯乙炔（PMOBOPV）、聚（2-甲氧基-5-己氧基）对苯乙炔（PMOHOPV）、聚（2,5-二丁氧基）对苯乙炔（PDBOPV）和聚（2,5-二己氧基）对苯乙炔（PDHOPV）等四种可溶性聚对苯乙炔（PPV）衍生物，通过紫外-可见吸收光谱对产物分子结构进行表征.结果显示，PMOBOPV、PMOHOPV、PDBOPV和PDHOPV的共轭π电子发生π → π* 跃迁的吸收峰分别位于491 nm、495nm、504nm和510nm处，相应的光学禁带宽度分别为2.23eV、2.18eV、2.12eV和2.07eV.利用简并四波混频技术测量PPV衍生物的三阶非线性光学性能，探讨了分子结构对PPV衍生物三阶非线性极化率（χ(3)）的影响.研究发现，激发波长为532 nm时，PMOBOPV、PMOHOPV、PDBOPV和PDHOPV的共振χ(3)值分别为3.45×10－10、5.13×10－10、7.15×10－10和9.61×10－10 esu；激发波长为1064 nm时，它们的非共振χ(3)值分别为1.09×10－11、1.42×10－11、1.62×10－11和2.14×10－11 esu.     

非晶SiO2薄膜中氧双键缺陷电子及光学特性的第一性原理研究

利用第一性原理对离子溅射沉积的非晶SiO2薄膜微观结构进行了分析、研究,结果表明,氧双键缺陷（SGs）可以作为体缺陷稳定存在于非晶SiO2中,SGs缺陷导致非晶SiO2薄膜材料禁带中引入了新的电子态,减小了禁带宽度;同时采用时相关密度泛函理论（TDDFT）对其光学特性进行了研究,得到非晶SiO2薄膜介电常数与入射光子能量间的关系曲线,从介电常数的虚部发现SGs缺陷在3.6eV处存在一个光学吸收峰。     

一维光子晶体微腔的光放大和耦合腔的滤波特性研究

用传输矩阵法(TMM)研究了由SiO2和TiO2组成的一维光子晶体微腔的放大特性和耦合腔光子晶体的滤波特性.结果表明:在微腔光子晶体的缺陷层中掺杂一定浓度的Er+3,则对中心波长λ0=1.532μm,可以实现光放大;而二耦合腔或三耦合腔光子晶体可以作为二波长或三波长的滤波片.     

溶胶-凝胶法制备Ce3+掺杂纳米SiO2材料光致发光研究

通过溶胶-凝胶技术制备了掺杂Ce^3＋离子的纳米SiO2材料,并经较低温度下煅烧,研究其光致发光（PL）性能。X射线衍射（XRD）及透射电子显微镜（TEM）测试结果表明该纳米材料具有非晶态结构,颗粒尺寸为20～30nm。对其光致发光谱的测定显示：经450℃低温煅烧,未掺杂SiO2样品的光致发光谱明显为多峰的宽带结构,而微量Ce^3＋掺杂的样品在230nm激发下存在着唯一的一个很强的、主峰位于346nm左右的紫外发光峰,与未掺杂SiO2及Cu^2＋掺杂SiO2样品的比较表明该发光峰并非常见的Ce^3＋离子的d-f跃迁产生的特征发光带,而是起源于SiO2中的某种本征缺陷中心。通过不同煅烧温度以及不同Ce^3＋离子掺杂量对346nm发光峰强度的影响,讨论该发光峰起源可能的结构模型。     

A Ftir and Raman Spectral Study of the Preparation of Lead Titanate (PbTiO3) by a Sol-Gel Method

Lead Titanate (FT) materials were prepared by a sol-gel process in an air atmosphere using lead acetate and titanium propoxide in methoxyethanol as the precursor materials. FTIR and Raman spectroscopy were used to characterize the various structural changes that occurred during various stages of the preparation. A new crystalline lead titanate phase was detected by both Raman spectral and X-ray diffraction techniques when heating the gelled material at 430°C. In-situ Raman spectra were measured at high temperatures for the resulting sol-gel prepared PT material to investigate its phase-transition and soft-mode behavior.     

Solar cell performance improvement via photoluminescence conversion of Si nanoparticles

Photoluminescence (PL) conversion of Si nanoparticles by absorbing ultraviolet (UV) lights and emitting visible ones has been used to improve the efficiency of crystalline Si solar cells. Si nanoparticle thin films are prepared by pulverizing porous Si in ethanol and then mixing the suspension with a SiO2 sol-gel (SOG).This SOG is spin-deposited onto the surface of the Si solar cells and dries in air. The short-circuit current as a function of Si nanoparticle concentration is investigated under UV illumination. The maximal increase is found at a Si concentration of 0.1 mg/mL. At such concentration and under the irradiation of an AM0 solar simulator, the photoelectric conversion efficiency of the crystalline Si solar cell is relatively increased by 2.16% because of the PL conversion.     

Synthesis,growth and properties of a novel organic nonlinear optical material: Benzimidazolium perchlorate

Benzimidazolium perchlorate (BDP) a novel organic nonlinear optical material has been grown by slow evaporation technique. Growth parameters such as metastable zone width and induction period were determined. The relative second harmonic generation (SHG) efficiency of the material was investigated for the first time in the literature and was found to be 1.2 times higher than that of KDP. The grown crystals were subjected to X-ray diffraction, absorption spectrum, Fourier transform infrared (FT-IR) spectroscopy, thermal behavior, CHN analysis, and micro hardness studies.     

Eu3+和Tb3+掺杂硅酸钇纳米粉体的合成与表征

采用溶胶-凝胶法合成了Y₂SiO₅∶Eu和Y₂SiO₅∶Tb纳米粉体,使用X射线衍射仪、扫描电镜等对粉体的结构、形貌和发光性能进行了分析,研究了Eu³⁺和Tb³⁺不同浓度掺杂硅酸钇纳米粉体的发光性能。在紫外光激发下,所获得的Y₂SiO₅∶Eu纳米粉体的主发射峰均位于612 nm,对应于Eu³⁺的⁵D₀→⁷F₂跃迁;Y₂SiO₅∶Tb纳米粉体的主发射峰均位于540 nm,对应于Tb³⁺的⁵D₄→⁷F₅跃迁。     

压敏漆基质SiO2溶胶制备及其性能研究

以正硅酸乙酯为前驱体，乙醇为溶剂，盐酸为催化剂，采用溶胶-凝胶法制备了用于压敏漆基质薄膜材料的SiO2溶胶。不同的成膜助剂对SiO2溶胶的涂膜性能影响较大，其中以异丙醇作为添加剂的溶胶涂膜性能最好。吸收光谱测试结果表明SiO2溶胶不吸收激发光，同时发射光谱研究结果表明SiO2溶胶发光波长为415nm左右，不影响压敏漆探针分子的发光。     

溶胶-凝胶法制备光波导薄膜及性质的研究

采用有机改性硅酸盐制备了光敏性溶胶－凝胶,并在凝胶中加入四丙氧基锆作为调节折射率的材料;用该凝胶在硅片上提拉成膜.为了增加薄膜与硅片的粘附性,成膜前先用干氧热氧化法在硅片上生长了一层厚度约为1500的二氧化硅;样品的原子力相片表明薄膜的表面非常平整,在5×5 μm2的范围内最大表面起伏只有0.657 nm.利用波导阵列掩膜版, 对制备的薄膜在紫外光波段下曝光,得到了表面平坦、侧墙光滑、陡直的沟道波导阵列.研究发现:紫外曝光时间和坚膜时的后烘温度都会使薄膜的折射率增大.通过对样品红外吸收谱的分析,从微观机理上解释了折射率随工艺条件变化的原因.     

Fluorescent enhancement effect in heterometallic terbium-lanthanum hybrid molecular materials obtained by functional bridge grafting to silica network

A new monomer, TBBA-APMES, has been synthesized by grafting 3-aminopropyl-methyl-diethoxylsiliane (APMES) to 4-tert-butylbenzoic acid (TBBA) and characterized by H NMR, C NMR and Fourier transform infrared (FT-IR). The monomer acts as a functional ligand for Tb and La ion and as a sol-gel precursor. Luminescent hybrid materials consisting of terbium-lanthanum complex covalently bonded to a silica-based network have been obtained in situ via a sol-gel approach. Through the co-hydrolysis and polycondensation, Tb³⁺ and La³⁺ can be introduced in the same molecular hybrids through the chemical Si-O network and fluorescent enhancement is observed. The luminescent behavior has been studied with the different ratios of Tb³⁺-La³⁺, suggesting that the luminescence intensities of hybrids can be enhanced obviously by the existence of La³⁺. The enhanced fluorescence effect may be due to the strengthening of intramolecular energy transfer efficiency by La³⁺.     

Zn、Cu共掺杂TiO_2∶SiO_2薄膜材料的光学性能研究

用溶胶-凝胶法制得Zn、Cu共掺杂的TiO_2∶SiO_2凝胶,旋转法于玻璃基底涂膜,制得Zn、Cu共掺杂的TiO_2∶SiO_2薄膜,探讨了煅烧温度、煅烧时间及掺杂比例对其结构、形貌和性能的影响。采用XRD、FESEM、FTIR等测试技术对薄膜进行表征,并考察了其对甲基橙的光催化降解性能。XRD测试结果显示:薄膜样品的晶型为锐钛矿型,结晶良好。SEM谱图显示:薄膜微粒粒径小,分布均匀,表面平整、致密且无明显裂痕;紫外-可见光谱(UV-Vis)表明:Zn、Cu共掺杂的TiO_2∶SiO_2薄膜在紫外区和可见光区的吸光度明显增加,提高了对光的利用率;光催化性能测试表明:与纯相TiO_2对比,Zn、Cu共掺杂的TiO_2∶SiO_2薄膜对甲基橙的光催化降解率有较大提高,在600℃下焙烧2h的掺杂的量比为n(Ti)∶n(Si)∶n(Zn)∶n(Cu)=3∶2∶1.5∶4的薄膜样品光催化降解率最高。     

Preparation of TiO2-carbon surface composites with high photoactivity by supercritical pretreatment and sol-gel processing

TiO₂-carbon surface (TCS) composites were prepared by pretreatment of a sealing substrate in supercritical carbon dioxide using paraffin as a plugging agent, and sol-gel processing using tetrabutyl orthotitanate as a precursor. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectrum (XPS), optical absorption spectroscopy and nitrogen absorption. The photoactivity of TCS was checked by monitoring the decomposition of methylene blue (MB) in aqueous solution under UV irradiation. The results indicated that compared with TC prepared only by the sol-gel method, the small nanosize TiO₂ particles are well dispersed on carbon surface with large amount of micropores and high Eg values, meanwhile TCS have high Ti³⁺ concentration due to supercritical pretreatment providing a amount of carbon on the composite surface with interfacial energy effects, which controls the growth of TiO₂ nanoparticles, baffles the agglomeration of TiO₂ nanoparticles and easily produces Ti³⁺ ions. These are reasons why TCS has a higher efficiency of decomposing MB than TiO₂-carbon (TC) composites and pure TiO₂. Additional, it is also attributed to the fact that TCS produce a high concentration of organic compounds near TiO₂ in comparison with TC and pure TiO₂, because their surface area are greater than that of TC and pure TiO₂.     

Influence of transition metal doping on tris(thiourea)zinc(II) sulphate crystals

Optical, thermal and dielectric properties of Ni(II)-doped tris(thiourea)zinc(II) sulphate single crystals grown by slow evaporation solution growth technique has been investigated. The lattice parameters of the as-grown crystals were obtained by single crystal X-ray diffraction analysis. The modes of vibrations of different functional groups present were identified by FT-IR studies. The surface morphological changes are observed in the doped specimen. The structure and the crystallinity of the material were confirmed by powder X-ray diffraction analysis. The UV–vis optical absorption spectrum shows the lower optical cut-off at ∼284 nm and the crystals are transparent in the entire visible region. The relative second harmonic generation efficiency measurements reveal the enhancement of efficiency by doping with small quantities of Ni(II).