硅烷偶联剂表面接枝包覆纳米SiO2的研究

采用硅烷偶联剂γ-（甲基丙烯酰氧）丙基三甲氧基硅烷（MPS）处理纳米SiO2,并用FT-IR、ζ-电势、TG、TEM对纳米SiO2的处理效果进行了表征.结果表明,纳米SiO2的接枝率随偶联剂MPS加入量的增加而增加;当pH值为4,MPS/SiO2为50%,反应温度为110 ℃、时间为90 min时,纳米SiO2表面MPS的接枝包覆率达到35.7%;此时纳米SiO2粒子在乳液中的分散更为均匀.     

纳米TiO2表面包覆致密SiO2膜的试验研究

用液相沉积法对纳米二氧化钛进行了表面改性.用XRD、FT-IR分析手段对其进行了表面结构表征,采用X衍射荧光光谱仪(XRF)测定SiO2包覆量随陈化时间的变化.通过煅烧失重法比较改性前后样品的失重,并用动态法测量样品与水的湿润角.结果表明在TiO2表面存在致密非晶态的硅氧化合物膜,纳米TiO2与水的湿润角增大,并且充分分散后在水中的稳定性却得到了很大提高.     

纳米SiO2氢氧化铝/十二烷基苯磺酸钠的表面包覆改性

通过氢氧化铝和十二烷基苯磺酸钠(SDBS)对纳米SiO2进行表面包覆和改性处理,改善纳米SiO2的表面结构和分散性.使用IR、FESEM、EDS、Malvern Zetasize 3000HSA自动电位粒度仪等表征手段,对表面包覆改性后纳米SiO2的表面结构、形貌及等电点等进行了测试和分析.结果表明,经Al(OH)3表面包覆后,纳米SiO2粉体等电点(IPE)的pH值从1.58变为7.1;经SDBS对表面包覆Al(OH)3的纳米SiO2进行改性后,纳米SiO2粉体团聚现象减少,单个纳米SiO2颗粒的粒径约为30nm.     

8-羟基喹啉铝纳米结构的可控制备

利用简单的物理气相沉积制备了多种纳米结构的8-羟基喹啉铝(AlQ3),主要考察了温度对其微结构的影响.运用傅立叶红外光谱仪、环境扫描电子显微镜、紫外光致发光仪等对其进行了结构、形貌和光致发光特性的研究.结果表明:成功制备了AlQ3纳米链,AlQ3纳米片,AlQ3微米球与纳米线的复合结构.PL谱没有明显的变化,可能是因为AlQ3分子间结合力是较弱的范德华力.     

8-羟基喹啉铝的老化研究

8－羟基喹啉铝（Alq3）是一种非常重要的电致发光材料，无论是从基础理论研究的观点来看，还是就其应用价值而言，均引起人们的极大关注。本文综述了Alq3的老化机理，分析了影响Alq3老化的主要因素，并对防止Alq3老化方法进行了简单介绍。     

用液相沉积法在铝酸锶荧光粉表面包覆SiO2和Al2O3复合膜

铝酸锶是典型的长余辉发光材料,已经广泛应用于日常生活中,但是铝酸锶在水中极易发生水解,抗湿性差,严重限制了其应用。采用化学气相沉积法和物理蒸汽沉积法在长余辉发光材料表面包覆膜,对设备要求高,价格贵,不易推广。因此,采用液相沉积法在长余辉荧光粉铝酸锶表面包覆SiO2膜和A l2O3膜来提高其耐水性能,采用电镜扫描(SEM)、X射线衍射(XRD)表征膜的存在,并对包膜试样进行了耐水性和发光性能的测试。结果表明:铝酸锶荧光粉包覆了致密的复合膜层后,耐水性得到显著的提高,同时,包膜对荧光粉的发光性能影响较小,发射光和激发光强度损失均在10%以下。     

液相法在Gd2O3:Eu表面包覆SiO2的研究

采用液相法成功的在球形Gd2O3Eu荧光粉颗粒表面包覆一层纳米SiO2保护膜.扫描电镜分析可见包覆SiO2后颗粒粒径略微变大说明表面包覆一层纳米级的包覆层.XPS分析表明SiO2包覆层与Gd2O3Eu颗粒表面以Gd(Eu)-O-Si化学键的方式键合在一起的.荧光光谱分析表明包覆后的Gd2O3Eu3+颗粒仍旧是一种很好的发光材料.     

LED用YAG:Ce3+荧光粉包覆SiO2膜的研究

选用热稳定性好、无色透明的SiO2为包覆物,采用溶胶法,以正硅酸乙酯(TEOS)为硅源,对YAG:Ce3+荧光粉的表面进行SiO2膜的包覆研究,以解决LED荧光粉在使用过程中突出的热劣化问题.采用X射线衍射(XRD),扫描电子显微镜(SEM),透射电子显微镜(TEM)和荧光光谱(FS)等对包膜前后的YAG:Ce3+荧光...     

纳米SiO2表面改性及其分散性能研究

采用过氧化氢溶液对纳米二氧化硅(SiO2)粉体进行表面预处理;以γ-(甲基丙烯酰氧)丙基三甲氧基硅烷为改性剂,在水相一油相混合溶液中,对预处理后的纳米SiO2粉体进行表面改性.对改性前后的纳米SiO2粉体采用傅立叶变换红外光谱、紫外一可见光光谱仪、粒径分析等方法进行表征与检测.结果表明:过氧化氢能有效防止纳米Sio2粉体团聚,表面改性后纳米SiO2粉体能均匀分散到有机溶剂中.     

Pentcene/SiO2表面随温度变化的AFM研究

以热氧化硅片为衬底,以溶液溶解和真空蒸镀两种方法,在不同温度下制备有机半导体材料并五苯(pentacene)薄膜.用原子力显微镜(AFM)分析了薄膜的形貌,讨论了影响薄膜质量的各种因素.     

颜料铝粉包覆SiO2的研究

以硅酸钠(Na2SiO3)为原料在颜料铝粉表面包覆SiO2,研究了SiO2/Al质量比(m(SiO2)/m(Al))、温度和pH值对铝粉析氢的影响,研究表明,最佳包覆条件为:m(SiO2)/m(Al)=7.5%,T=75℃,pH=9.5.并运用光学显微镜、SEM、IR和XRD对包覆样品进行了分析与表征.     

Preparation of 8-hydroxyquinoline wires by decomposition of tris(8-hydroxyquinoline) aluminium

We fabricated 8-hydroxyquinoline (HQ) wires by two methods, decomposition of tris(HQ) aluminium at low pressure in a tube furnace and heating of HQ powder at atmospheric pressure. Fabricated wires were crystalline, and exhibited the same optical properties (absorption and photoluminescence) as HQ powder. While the properties of wires prepared by two different methods were the same, it should be noted that synthesis by decomposition of tris(HQ) aluminium required elimination of mechanical vibration of the growth tube. Implications of decomposition of tris(HQ) aluminium during organic vapour phase deposition growth on organic optoelectronic device performance are discussed.     

Mg2SiO4固相合成及其性能研究

以碱式碳酸镁和SiO2为原料,采用固相反应法合成MgzSiO4.结果表明,当Mg/Si比为2∶1.2,在1200℃以上空气气氛中预烧3h,能合成出单相的Mg2SiO4.在1280～1340℃保温2h烧结成瓷后,其1MH2介电常数为7.05±0.05,损耗角正切变化范围在(2～5)×10-4之间,体积密度为(3.1±0.5)g/cm3.     

Organometallic tris(8-hydroxyquinoline)aluminum complexes as buffer layers and dopants in inverted organic solar cells

Tris(8-hydroxyquinoline)aluminum (Alq₃) is a frequently used material for organic light emitting diodes. The electronic properties and solubility can be tuned by chemical tailoring of the quinoline part, which makes it an interesting candidate for organic solar cells. Steady-state absorption and fluorescence, as well as time-resolved fluorescence properties of the parent Alq₃ and a series of complexes consisting of derivatives, such as 4-substituted pyrazol, methylpyrazol, arylvinyl, and pyridinoanthrene moieties, of the quinoline ligand, were studied in solutions and in thin films. Suitability of the complexes as anodic buffer layers or dopants in inverted organic solar cells based on the well known bulk heterojunction of poly(3-hexylthiophene) (P3HT) and phenyl-C₆₁-butyric acid methyl ester (PCBM) was tested. The devices equipped with the derivatives showed higher power conversion efficiency (η) compared to the photocells containing the parent Alq₃. Open circuit voltage (V_oc) was increased when the derivatives were utilized as the anodic buffer layer. Doping of the P3HT:PCBM with a small amount of Alq₃ or its derivative improved short circuit current density, V_oc, fill factor, and η, while the series resistance decreased. In addition, the devices were stable in air over several weeks without encapsulation. Possible mechanisms leading to the improvements in the photovoltaic performance by using the parent Alq₃ or its derivative as buffer layer or dopant are discussed.     

Temperature-independent electron tunneling injection in tris (8-hydroxyquinoline) aluminum thin film from high-work-function gold electrode

We fabricated electron-only tris (8-hydroxyquinoline) aluminum (Alq₃) single-layer devices with a device structure of glass substrate/MgAg anode (100 nm)/Alq₃ layer (100 nm)/metal cathode (100 nm), and systematically varied the work functions (WF) of the metal cathodes from WF = − 1.9 (Cs) to − 2.9 (Ca), − 3.8 (Mg), − 4.4 (Al), − 4.6 (Ag), and − 5.2 eV (Au) to investigate how electron injection barriers at the cathode/Alq₃ interfaces influence their current density–voltage (J–V) characteristics. We found that current densities at a certain driving voltage decrease and the temperature dependence of J–V characteristics of the devices gradually becomes weaker as the work functions of the metal cathodes are decreased. The device with the highest-work-function Au cathode exhibited virtually temperature-independent J–V characteristics, suggesting that a current flow mechanism of this device is mainly controlled by electron tunneling injection at the Au/Alq₃ interface.     

新型闪烁晶体Ln2SiO5的研究进展

作为新型无机闪烁晶体材料,稀土硅酸盐系列晶体Ln2SiO5(Ln-Gd3+,Y3+,Lu3+)近年来受到广泛关注.本文综述了Ln2SiO5系列晶体的结构,Ce3+荧光机制及晶体生长研究的进展,总结了它们的闪烁性能,应用和有待深入研究的问题.     

Improvement of amplified spontaneous emission performance by doping tris(8-hydroxyquinoline) aluminum (Alq3) in dye-doped polymer thin films

A well-known red fluorescent dye 4-(dicy-anomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) was codoped with an electron transport organic molecule tris(8-hydroxyquinoline) aluminum (Alq(3)) in a host matrix of polystyrene (PS), and the amplified spontaneous emission (ASE) was studied by optically pumping. It was found that the ASE performance was significantly improved by the introduction of Alq(3). The Alq(3):DCJTB:PS blending thin films showed a low threshold (2.4 microJ/pulse) and a high net gain coefficient (109.95 cm(-1)) compared with the pure DCJTB:PS system (threshold of 15.2 microJ/pulse and gain of 35.94 cm(-1)). The improvement of the ASE performance was considered to be attributable to the effective F?ster energy transfer from Alq(3) to DCJTB. Our results demonstrate that the Alq(3):DCJTB could be a promising candidate as gain medium for red organic diode lasers.     

溶胶-凝胶法制备透明超疏水性SiO2涂层

用溶胶-凝胶法制备出粒径分别为50nm、180nm的SiO2胶粒,用硅烷偶联荆对这2种胶粒进行表面修饰,使胶粒表面分别带有氨基与环氧基官能团.通过控制工艺,使表面带有不同官能团的SiO2胶粒组装,获得具有两种胶粒复合结构的胶体.采用浸渍提拉法镀膜,并用氟硅烷对涂层进行表面修饰,制备出透明超疏水性涂层.采用扫描电镜、透射电镜、紫外可见分光光度计和接触角测量仪等对涂层进行表征.结果表明,水滴在涂层上的平均接触角达到160°,滚动角接近0°,同时涂层的透光性超过80%.     

SiC/SiO_2包覆Fe-Ni合金纳米粒子的制备及应用

采用电弧放电法,在15%CH4+10%SiH4+75%Ar的混合气氛中制备了SiC/SiO2包覆Fe-Ni合金纳米粒子,并用制备的SiC/SiO2包覆Fe-Ni合金纳米粒子作为磁性粒子,油酸为表面活性剂,机油为基液制备了磁性润滑油。用XRD、TEM、XPS、红外光谱和氧含量分析等手段研究了SiC/SiO2包覆Fe-Ni合金纳米粒子的相结构、形貌、粒度、表面组成和氧化特性。用粘度计和VSM研究了制备的磁性润滑油的粘度和饱和磁化强度。     

SiO2包覆对片状金属磁粉微波介电常数的影响

对片状金属磁性微粉进行表面改性,获得金属磁粉/SiO2核-壳结构复合粒子.用SEM对磁粉表面SiO2纳米粒子膜的形貌进行表征,并研究了共溶剂类型、加料工艺等因数对二氧化硅包覆膜的影响以及正硅酸乙酯(TEOS)用量对金属磁粉/SiO2复合粒子电磁参数的影响.结果表明以异丙醇为共溶剂,采用逐滴滴加TEOS的方式获得的SiO2包覆膜比较致密均匀;SiO2纳米粒子吸附在磁粉表面,形成高电阻率的包覆膜,导致其介电常数下降.