透明β-NaYF4：Yb,Tm/PMMA 纳米复合材料的制备及其光学性能

采用高温溶剂热法制备了一系列不同Yb³⁺掺杂浓度的上转换发光纳米粒子β-NaYF₄：Yb,Tm和核壳结构的β-NaYF₄：Yb,Tm@β-NaYF₄：Yb纳米粒子。采用X射线衍射（XRD）、场发射扫描电镜（FESEM）、光致发光（PL）谱对材料的物相结构、形貌特征和发光性质进行了表征和研究,并特别研究了温度对材料发光性能的影响。结果表明：保持Tm³⁺浓度不变,随着Yb³⁺掺杂浓度的增加,β-NaYF₄：Yb,Tm的发光强度先增大后减小。当Yb³⁺掺杂摩尔分数为30%时,474 nm和645 nm处的发光强度达到最大值;当Yb³⁺掺杂摩尔分数为50%时,450 nm和692 nm处的发光强度达到最大值。在β-NaYF₄：Yb（30%）,Tm上包裹一层β-NaYF₄：Yb壳层后,其发光显著增强,随壳层Yb³⁺摩尔分数的增加,发光强度也是先增大后减小。当壳层Yb³⁺摩尔分数为10%时,核壳结构纳米粒子的发光强度达到最大值;当壳层Yb³⁺摩尔分数达到40%时,核壳结构纳米粒子的发光强度已经低于未包裹时。将样品进行热处理后,荧光增强。样品的发光强度随环境温度的升高,红光变弱,蓝光增强。采用原位聚合法将β-NaYF₄：Yb,Tm纳米粒子与PMMA制成复合材料后,仍能保持较好的透明度和发光强度。     

光谱稳定的互补色双发光层高效混合白光OLED

利用两种颜色的发光层制备了光谱稳定的高效混合WOLED。其中蓝光发光层用14%质量分数的BNE掺杂在BePP₂中,橙光发光层用1%质量分数的Ir（bt）₂（acac）掺杂在49.5%质量分数的NPB和49.5%质量分数的BePP₂组成的混合主体中。在不利用任何光耦合技术的条件下,器件在亮度为100 cd/m²时,功率效率可以达到39 lm/W;当亮度提高到1 000 cd/m²时,效率仅发生轻微滚降至27.5 lm/W。器件的光谱稳定,亮度在1 000 cd/m²和10 000 cd/m²时,CIE坐标分别为（0.37,0.48）和（0.37,0.47）。良好的光谱稳定性归结于设计的双极性中间层平衡了其两侧激子的产生。     

高压对纳米ZnO和ZnO/SnO2复合材料的结构和发光性能的影响

 利用溶胶-凝胶法制备出了纳米晶ZnO与含有3%摩尔分数SnO₂的ZnO/SnO₂复合材料,在六面顶压机上对制备出的两种样品进行了室温下、6GPa的高压处理。采用X射线衍射（XRD）、透射电子显微镜（TEM）和光致荧光谱（PL）等方法,对高压处理前后样品的结构和发光性质进行了表征。结果表明：高压处理后回收到的纳米晶ZnO和ZnO/SnO₂复合材料的平均粒径分别减小5.9%和26.3%;高压处理后ZnO和ZnO/SnO₂复合材料光致发光谱的发光带强度都有所降低,但ZnO/SnO₂复合材料发光带强度降低幅度比纯ZnO小,对产生这些现象的原因进行了讨论。     

Fe、Ni共掺杂ZnO基稀磁半导体光学性能与铁磁性研究

采用水热法成功制备了不同掺杂浓度的Zn_1-2xFe_xNi_xO（x=0,0.025,0.05,0.1）稀磁半导体材料,利用X射线衍射（XRD）、透射电子显微镜（TEM）和X射线能量色散分析仪（XEDS）对样品进行表征,并结合拉曼（Raman）光谱、光致发光光谱（PL）和振动样品磁强计（VSM）研究样品的光学性能和磁学性能。结果表明,水热法制备的样品具有结晶性良好的纤锌矿结构,没有杂峰出现,形貌为纳米棒状结构,分散性良好。Fe²⁺、Ni²⁺是以替代的形式进入ZnO晶格中,Fe和Ni的掺杂使得晶体中的缺陷和应力增加,拉曼光谱峰位发生红移,光致发光光谱发生猝灭现象。另外,共掺杂样品在室温条件下存在明显的铁磁性,饱和磁化强度随着掺杂量的增加而增强。     

Fe3O4纳米粒子对P3HT:PCBM电池的影响

为了提高太阳能电池的性能,研究磁性纳米粒子在外加磁场的作用下对聚合物太阳能电池有源层P3HT:PCBM成膜及太阳能电池性能的影响。本文采用热分解法制备了磁性Fe₃O₄纳米粒子,将不同质量分数的Fe₃O₄纳米粒子掺入到P3HT:PCBM溶液中,旋涂后在外加磁场的作用下自组成膜。通过TEM、XRD对制备的Fe₃O₄纳米粒子进行表征,并利用偏光显微镜、原子力显微镜对成膜质量进行探究。结果表明,采用热分解法制备的Fe₃O₄纳米粒子直径在10 nm左右,在外加磁场作用下,Fe₃O₄纳米粒子对成膜有一定的调控作用。当Fe₃O₄纳米粒子掺杂质量分数为1%时,太阳能电池器件的开路电压增加3.77%,短路电流增加24.93%,光电转换效率提高7.82%。     

发光二极管用SrWO4:Eu3+红光荧光粉激发谱强度的调控

采用化学共沉淀法制备了Eu³⁺掺杂摩尔分数不同、煅烧温度不同的SrWO₄:Eu³⁺系列发光粉体, 所制备的粉体均具有Eu³⁺特征的强室温红光荧光发射. 通过调节煅烧温度和掺杂摩尔分数来调控近紫外和蓝光吸收强度, 进而调控用395 nm的近紫外光和465 nm的蓝光激发样品所得红光发光强度. 研究结果表明, 所制备的SrWO₄:Eu³⁺红光荧光粉可以被紫外和蓝光发光二极管有效激 关键词： 稀土掺杂 4:Eu³⁺')" href="#">SrWO₄:Eu³⁺ 光致发光 白光发光二极管     

催化剂对热蒸发法生长SnO2纳米晶体质量的影响及其发光光谱研究

用热蒸发法制备了SnO₂纳米结构，并用光致发光方法研究了其光谱特性.发现有催化剂条件下制备的SnO₂纳米带的发光主峰为3.68 eV, 正对应SnO₂纳米晶体的带隙能量; 而无催化条件下制备的SnO₂纳米晶体的发光则以氧空位、悬键和表面态发光为主.并且前者的发光效率比后者提高近两个数量级，这些实验结果说明在有催化条件下制备了高质量的SnO₂纳米带.另外,对其发光光谱进行了Gauss拟合, 从拟合结果发现了(101)和(101)_T孪生晶面的表面态的发光峰. 关键词： 光致发光光谱 半导体纳米晶体 催化剂 2')" href="#">SnO₂     

强磁场下NH4Cl水溶液结构的拉曼光谱研究

迄今为止,国内外存在很多关于强磁场处理对水溶液结构影响的争议,并且关于强磁场对无机盐水溶液结构的研究也相对较少。运用拉曼光谱法,测定了在外加强磁场1.8 T强度下,高纯水与质量分数分别为1%,5%,10%,20%和28%的NH₄Cl水溶液在不同磁化时间下的拉曼散射数据,为拉曼光谱法探究强磁场对水溶液结构的影响提供了一个新的可行方式,丰富了拉曼光谱的研究领域。由实验结果可知,随着磁化时间的增加,水分子中氢键的伸缩振动峰值逐渐升高,经过一定的磁化时间后可以达到饱和。高纯水与不同质量分数的NH₄Cl水溶液的饱和效应时间均不同。高纯水与质量分数为1%,5%,10%,20%和28%的NH₄Cl水溶液峰值饱和时间分别为150,120,120,100,80和80 min。随着NH₄Cl水溶液质量分数的增加,达到磁效应饱和的时间呈现减少的趋势。磁场移除后,测定高纯水与不同质量分数NH₄Cl水溶液的去磁记忆时间。高纯水与质量分数为1%,5%,10%,20%和28%的NH₄Cl水溶液的去磁记忆时间分别为30,40,50,60,80和80 min。随着NH₄Cl水溶液质量分数的增加,去磁记忆时间呈现增加的趋势。利用去卷积拟合的方法对磁化2 h后不同质量分数的NH₄Cl水溶液进行处理。由去卷积拟合结果可知,质量分数为20%的NH₄Cl水溶液比质量分数为10%的NH₄Cl水溶液增加了一个N-H峰,该信号峰随着NH₄Cl水溶液质量分数的增大逐渐增强。DDAA型氢键结构整体上随磁化时间增加而减少,磁化时间的增加对四面体水结构具有破坏作用。当达到饱和磁化时间后,DDAA型氢键不再发生变化。实验结果表明,通过拉曼光谱法可以得到1.8 T强磁场对NH₄Cl水溶液结构的影响规律,为外加强磁场条件下其他无机盐水溶液的研究提供了一定的理论基础。     

氮化硅薄膜中纳米非晶硅颗粒的键合结构及光致发光

采用螺旋波等离子体化学气相沉积技术以N₂/SiH₄/H₂为反应气体制备了镶嵌有纳米非晶硅颗粒的氢化氮化硅薄膜,通过改变N₂流量实现了薄膜从红到蓝绿的可调谐光致发光.傅里叶红外透射和紫外-可见光吸收特性分析表明,所生长薄膜具有较高的氢含量,N₂流量增加使氢的键合结构发生变化,非晶硅颗粒尺寸减小,所对应的薄膜的光学带隙逐渐增加和微观结构有序度减小.可调光致发光(PL)主要来源于纳米硅颗粒的量子限制效应发光,随N₂流量增加,PL的谱线展宽并逐渐增强. 关键词： 傅里叶红外透射谱 光吸收谱 纳米硅粒子镶嵌薄膜 光致发光     

三水合醋酸钠纳米成核剂的性能研究

三水合醋酸钠是一种具有较高的储能密度和热导率的储热相变材料,但是在凝固过程中的过冷和相分离现象限制了它的应用,需要寻求有效的成核剂和增稠剂来克服过冷和相分离的问题。本文实验分析了几种纳米材料（AIN、Si₃N₄、ZrB₂、SiO₂、BC₄、SiB₆）的成核效果,结果表明质量分数5%或4%的Si₃N₄、10%ZrB₂、5%AlN在自然分散下就能够消除三水合醋酸钠过冷度,质量分数2%的SiO₂在熔化的三水合醋酸钠中经磁力搅拌和超声分散后能够消除其过冷度。结合纳米材料的粒度分析结果,表明粒度分布在几十纳米到300纳米左右的纳米材料有较好的成核效果。     

Stably dispersible P3HT/ZnO nanocomposites with tunable luminescence by in-situ hydrolysis and copolymerization of zinc methacrylate

In this paper, the copolymer shell with the internal hydrophobic polymethacrylate layer and the external hydrophilic poly(ethylene glycol) methyl ether groups was successfully bonded on the surface of ZnO nanocrystals through a simple sol–gel method, i.e., radical polymerization of zinc methacrylate (Zn(MA)₂) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) and hydrolysis. The prepared ZnO@poly(methacrylate-co-poly(ethylene glycol) methyl ether methacrylate) (ZnO@PPEGMA) nanocrystals showed good dispersion and smaller particle size, due to the presence of copolymer shell. The optical properties of ZnO@PPEGMA nanocrystals were characterized by ultraviolet–visible (UV–vis) spectroscopy and photoluminescence (PL) spectroscopy. The results indicated that the absorption edge and PL emission in the UV region of ZnO@PPEGMA nanocrystals appeared obvious blue-shift, due to the smaller particle size. Incorporation of ZnO@PPEGMA nanocrystals into poly(3-hexylthiophene) (P3HT) matrix, the dispersion of P3HT/ZnO@PPEGMA nanocomposites was greatly improved and the nanocomposites possessed excellent photoluminescence stability. Meanwhile, it was observed that the PL emission of P3HT/ZnO@PPEGMA nanocomposites was enhanced significantly, due to the presence of copolymer shell and the improvement of compatibility of ZnO@PPEGMA in the P3HT matrix. The results showed that the P3HT/ZnO@PPEGMA nanocomposites could be potential candidates for optical applications.     

石英衬底上Au缓冲层对ZnO薄膜微结构的影响

采用单源化学气相沉积(SSCVD)法,在石英衬底上以Au为缓冲层,Zn4(OH)2(O2CCH3)6.2H2O为固相源制备ZnO薄膜。SEM和XRD测试ZnO薄膜的微结构,结果表明:相对于SiO2衬底上生长的ZnO薄膜,Au/SiO2衬底上生长的ZnO薄膜具有较好的结晶质量和表面平整度;对制备ZnO薄膜的衬底温度进行了工艺优化,结果表明:500℃时制备的ZnO薄膜颗粒大小均匀,结晶质量较好;通过荧光光谱仪对Au/SiO2衬底上的ZnO薄膜进行光致发光(PL)谱测试,ZnO薄膜在400nm出现紫光发射峰,而没有出现与缺陷相关的深能级发射峰,表明ZnO薄膜具有较好的结晶质量。     

Luminescence of ZnO nanocrystals capped with an organic dye

ZnO nanocrystals capped with an organic dye Rhodamine 6G (Rh6G) were investigated by photoluminescence (PL) and cathodoluminescence (CL) techniques. PL and CL spectra showed a remarkable decrease in visible emission intensity after ZnO nanocrystals were capped with Rh6G, indicating that dangling bonds and defect states existing at the surface of ZnO nanocrystals were significantly passivated. Rh6G on the ZnO surface exhibited a monomer-like emission, and the intensity and the position of the emission were dependent on the dye concentration.     

The luminescence properties of the ZnO@ZnWO4:Eu core–shell composites

The ZnO@ZnWO₄:Eu³⁺ core–shell composites were prepared by a two-step hydrothermal method and the photoluminescence properties of the composites were studied in contrast to the corresponding hexagonal ZnO and monoclinic ZnWO₄: Eu³⁺ nanocrystals prepared by the one-step hydrothermal method. The results demonstrate that in the nanocomposites the Eu³⁺ ions in the ZnWO₄ phase occupy two symmetry sites, one a well-crystalline inner site and one a disordered surface site; while in the ZnWO₄: Eu³⁺ nanocrystals, the local environments surrounding Eu³⁺ ions are relatively disordered for both the inner and the surface sites. This indicates that in the composites, the crystallinity of the ZnWO₄ becomes better, which have positive influence on the improvement of photoluminescence. The temperature stabilities for both the emissions of ZnO and Eu³⁺ ions are improved in contrast to the pure ZnO or ZnWO₄:Eu³⁺ nanocrystals.     

ZnO filled opal arrays: Photo and cathodoluminescence studies

The photo and cathodoluminescence of zinc oxide (ZnO) filled opal arrays, as well as ZnO nanocrystals prepared by a chemical deposition method were investigated. The photoluminescence (PL) from the arrays was studied using angular resolution. The PL spectra of the filled opal exhibited a dip corresponding to the array’s photonic band gap. ZnO nanocrystals embedded in the opal matrix demonstrated quenched excitonic emission while the opal matrix showed enhanced emission. This effect is explained by an energy transfer from ZnO nanocrystals to the opal matrix.     

紫外发光增强的石墨烯-氧化锌纳米复合物

采用溶剂热法在相同条件下分别制备了纯ZnO和石墨烯-氧化锌纳米复合物,通过SEM、TEM、拉曼和红外光谱等手段,对纳米复合物样品进行了形貌和结构表征。实验结果显示ZnO纳米颗粒成功地分散在少层石墨烯上。通过对比纯ZnO与复合物的形貌和光致发光谱,发现在没有石墨烯时,ZnO能够择优取向生长成六方棱柱,紫外发光峰弱且宽;在有石墨烯时,ZnO聚集成表面不规则的球形颗粒,紫外发光峰强且窄。上述结果表明ZnO形貌的变化和石墨烯的等离子体效应共同影响了ZnO的紫外发光,但石墨烯的表面等离子体效应起主导作用。     

水热合成ZnO:Cd纳米棒的微结构及光致发光特性

采用水热法制备了ZnO和不同掺杂浓度的ZnO:Cd纳米棒,通过SEM,XRD、拉曼光谱等的分析,研究了ZnO和ZnO:Cd的微结构并测试分析了其光致发光特性.结果表明,ZnO和ZnO:Cd纳米棒呈六角纤锌矿结构,Cd掺杂使得纳米棒体积更小.由于内部张应力的影响,Cd掺杂使得材料光学带隙减少.当掺杂浓度为2%时,合成的材料光致发光谱中出现了位于2.67 eV处,由导带底和Zn空位(VZn)缺陷能级跃迁造成的蓝光发射峰,并且Cd的掺入使得位于2.90 eV附近的紫光发射峰强度增强,对于研究ZnO蓝紫发光器件具有重要的意义.     

Synthesis and properties of CdSe Quantum Dot sensitized ZnO nanocomposites

In this work, zinc oxide nanocrystals with an average particle size of 13–22 nm are readily synthesized in aqueous medium by the wet synthesis method. Different sized nanocrystals obtained with change in calcination temperature are characterized by PL photoluminescence (PL) and UV–vis absorption spectroscopies, X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The average crystal size of the as prepared ZnO nanopowder is determined by XRD and was found to be in good agreement with the UV–vis absorption analysis. The quality of different ZnO nanopowders is confirmed by XRD spectra. On the basis of different characterizations, ZnO calcined for 1 h (due to its large size and less agglomeration) is chosen for synthesis of ZnO–CdSe nanocomposites with variable sized CdSe QD's (Quantum Dots). Nano-composites are synthesized using bifunctional linker molecule Mercaptopropionic Acid (MPA), and by directly adsorbing CdSe QD's over the surface of ZnO nanocrystals. The difference in charge transfer mechanism in ZnO–CdSe nanocomposites due to different crystallite size of CdSe QD's is studied. Higher crystallinity of ZnO–CdSe nanocomposites can be determined from XRD characterization. Size and mode of attachment in various ZnO–CdSe nanocomposites are determined by SEM studies.     

金属离子修饰的ZnS/PAMAM纳米复合材料的荧光性能研究

用荧光分光光度法研究了Zn2+,Mn2+,Cd2+,Na+,K+,Ag+,Cu2+和Pb2+等金属离子修饰的ZnS/PAMAM树形分子纳米复合材料的荧光发射性能。结果表明：不同金属离子修饰效果不同。Zn2+,Mn2+和Cd2+修饰后,ZnS/PAMAM树形分子纳米复合材料的荧光发射强度有不同程度提高;Ag+,Cu2+和Pb2+的修饰对荧光有不同程度的猝灭作用;而Na+和K+的修饰对荧光发射无明显影响。与修饰前相比,Cd2+离子修饰的ZnS/PAMAM树形分子纳米复合材料标记的潜指纹发射的蓝色荧光更加明亮,与背景反差更加明显。这对提高潜指纹的显现精度和准确率有很好的借鉴价值。     

In situ preparation and fluorescence quenching properties of polythiophene/ZnO nanocrystals hybrids through atom-transfer radical polymerization and hydrolysis

In this paper, a new approach for in situ preparing nanocomposites of conjugated polymers (CPs) and semiconductor nanocrystals was developed. Polythiophene grafted poly(zinc methacrylate) (PTh-g-PZMA) copolymer was synthesized by atom-transfer radical polymerization (ATRP) of zinc methacrylate (ZMA) initiated from the macroinitiator poly(2,5-(3-(bromoisopropyl-carbonyl-oxymethylene) thiophene)) (PTh-Br) with pendant initiator groups. Subsequently, the polythiophene grafted poly(methacrylate)/ZnO (PTh-g-PMA/ZnO) hybrid heterojunction nanocomposites were successfully prepared by in situ hydrolysis of PTh-g-PZMA casting films in alkaline aqueous solution. The structures of PTh-Br, PTh-g-PZMA and PTh-g-PMA/ZnO were confirmed by the proton nuclear magnetic resonance (¹H NMR) spectra, Fourier transform infrared (FTIR) spectra and X-ray photoelectron spectroscopy (XPS). The morphologies of PTh-g-PMA/ZnO films prepared for different hydrolysis time were observed in the cross-sections by scanning electron microscope (SEM). The SEM images revealed that ZnO nanocrystals were uniformly dispersed in polymers without any aggregation and the appearances of ZnO nanocrystals changed from nanoparticles to nanorods with the hydrolysis treatment time increasing. The optical properties of these nanocomposites were studied by ultraviolet-visible (UV-vis) absorption and fluorescence spectroscopy. UV-vis absorption spectroscopy showed that the adsorption band of PTh-g-PMA/ZnO hybrids was broader than that of PTh-Br, implying that the existence of ZnO nanocrystals increased the optical absorption region of hybrids. The photoluminescence (PL) spectra of the hybrids showed that fluorescence quenching occurred in PTh-g-PMA/ZnO blends and a maximum of 85% of the fluorescence intensity quenched in the PTh-g-PMA/ZnO obtained from treatment in NaOH aqueous solution for 2 h, which revealed the existence of photo-induced charge transfer between the polythiophene chains and ZnO. These results indicated that the hybrid heterojunction nanocomposites could be promising candidates for photovoltaic applications.