晶硅太阳电池原位光老化及热致输运机理

为研究晶体硅太阳电池在标准模拟光条件下的输出特性变化规律和电池内部载流子输运特性,采用原位光老化技术对被测电池进行光照处理,按标准测试实验流程测量电池的伏安特性及光谱响应等参量,发现原位光老化后太阳电池伏安特性各项参量衰减,导致电池效率降低;短波段光谱响应微量下降,是由于原位光老化过程中电池表面产生极微量的面缺陷导致经过硅表面的微量载流子被复合;而长波段响应明显降低,是由于晶硅内大量体缺陷被激活导致长波载流子在经过硅材料内部时被复合.随后将光老化后电池退火并测量比对电池各项特性参量,结果表明,退火对光老化后电池内部深层体缺陷具有较好的修复功能,但对浅层面缺陷没有修复功能,最终造成电池伏安特性参量和光谱响应只得到部分恢复.     

Nanoporous gold thin films synthesised via de-alloying of Au-based nanoglass for highly active SERS substrates

Nanoporous gold thin films have been fabricated through chemical de-alloying of Au-based nanoglass with a nanocolumnar structure, with composition Au₄₀Cu₂₈Ag₇Pd₅Si₂₀ (at.%), that had previously been deposited by magnetron sputtering. By varying the de-alloying conditions, gold ligaments ranging from 20 to 100?nm were obtained. The microstructure and chemical composition of the as-prepared films were characterised by various techniques. Surface-enhanced Raman scattering (SERS) of thin films was investigated using rhodamine 6G. The results indicate that the main microstructural features with interconnected ligaments and defects of nanoporous gold result in significant SERS enhancement.     

Au纳米粒子增强丙酮受激拉曼散射研究

受激拉曼散射(stimulated Raman scattering,SRS)具有激光的特性,并且容易获取不同波长的激光,从而成为调谐激光频率的重要途径之一。然而,由于其转化效率低,限制了它的实际应用。金属纳米粒子具有很强的表面增强效应,曾被广泛地用于增强拉曼散射而获得良好的效果。本文提出将金属纳米粒子的这种性质用于增强SRS。把Au纳米粒子混合于拉曼介质丙酮中,以532nm的纳秒脉冲激光作为激发光,研究了Au纳米粒子在丙酮中的浓度对丙酮SRS一阶Stokes光强的影响,并通过仿真计算对实验结果进行了解释和分析。     

Syntheses and crystal structures of polymeric ionic triorganotin esters of 3,5-pyridinedicarboxylic acid and 5-nitroisophthalic acid

The triethylammonium dicarboxylatotriorganostannates, [(C₂H₅)₃NH][R₃Sn(3,5-pdc)]?·?mH₂O (3,5-pdc?=?3,5-pyridinedicarboxylate) (m?=?1, R?=?Me 1; m?=?0, R?=?Ph 2, PhCH₂ 3, n-Bu 4), [(C₂H₅)₃NH][R₃Sn(5-nip)] (5-nip?=?5-nitroisophthalate) (R?=?Me 5, Ph 6, PhCH₂ 7, n-Bu 8) have been prepared from triethylamine, 3,5-pyridinedicarboxylic acid, 5-nitroisophthalic acid and triorganotin chloride. Complexes 1–8 have been characterized by elemental, IR, ¹H, ¹³C and ¹¹⁹Sn NMR analyses. Complexes 1, 2, 5 and 6 are also determined by single crystal X-ray diffraction. For 1, 2, 5 and 6, each carboxylate moiety is involved in coordination to a tin center via only one O atom showing that the Sn atoms are five-coordinate and exist in trigonal bipyramidal geometries. Moreover, for 2, 5 and 6, the nitrogen atoms of ammonium are hydrogen bonded to the pendant carboxyl oxygen. In 1, adjacent polymeric chains and triethylammonium are linked by hydrogen bonds through the co-crystallized water molecule, thus a 2D network is formed.     

Size control of phase‐separated liquid crystal droplets in a polymer matrix based on the phase diagram

When a mixture of liquid crystal (LC) and photo reactive monomer is irradiated by UV light, polymerization occurs and LC droplets form through phase separation, producing polymer dispersed LCs (PDLCs). Although size control of LC droplets and reduced amounts of LC in PDLC films are important in applications, precise size control of LC droplets at a low LC fraction has not yet been accomplished. In this study, the phase diagrams of the LC/initial monomer and the LC/polymer during polymerization were used to control LC droplet size at various LC fractions. Both the relative position of the sample in the initial phase diagram and the shift of the phase separation line during polymerization were shown to be important in determining the size of LC droplets. Our results are expected to provide a new strategy for precise size control of LC droplets especially at a low LC fraction range, which would be a great help for PDLC applications. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Preliminary communication Liquid crystalline cardanyl β-D-glucopyranosides

Two novel aryl glycosides were synthesized, which varied in the extent of unsaturation in the lipophilic part, from plant/crop-based renewable resource materials. Their liquid crystalline properties were characterized by optical polarizing microscopy, differential scanning calorimetry and X-ray diffraction. All the mesophases are identified as lamellar in structure.     

Crystal structure,spectroscopic properties,and DFT studies of 2-(2-hydroxyphenyl)benzo[d]oxazole-6-carbaldehyde

The title compound 2-(2-hydroxyphenyl)benzo[d]oxazole-6-carbaldehyde (1a) was synthesized and characterized by single-crystal X-ray diffraction. Compound 1a possesses intramolecular C–H···O and O–H···N hydrogen bonds, which generate S(5) and S(6) rings, respectively. Intermolecular π–π stacking is observed in the crystal structure, which links a pair of molecules into a cyclic centrosymmetric dimer. The crystal structure is further stabilized by three different intermolecular C–H···O hydrogen bonds, which link the molecules into a continuous three-dimensional framework. Its spectroscopic properties and complementary density functional theory (DFT) calculations are also reported.     

Synthesis and mesomorphism of ionic self-assembled complexes of anthraquinones

Anthraquinones are known to exhibit mesomorphism upon appropriate substitutions. In this report, the concept of ionic self-assembly has been applied to design and synthesise new anthraquinone-based liquid crystals. Four different anthraquinones were used as polyelectrolytes which form ionic complexes with double-tail ammonium surfactants. The chemical structures were characterised by spectral techniques and elemental analysis. The thermal behaviour of the complexes was investigated by polarising optical microscopy, differential scanning calorimetry, thermogravimetric analysis and X-ray diffraction studies. All these complexes display lamellar mesomorphism. The amphotropic nature of the complexes has also been studied.