光折变聚合物材料研究进展

综述了光致折变聚合物材料的分类方法和近年来光折变聚合物材料的发展状况，认为液晶光折变聚合物材料将有巨大的应用前景。     

掺铜铌酸钾锂晶体光折变效应的研究

在铌酸钾锂晶体中掺进ＣｕＯ,采用Ｃｚｏｃｈｒａｌｓｋｉ法生长Ｃｕ：ＫＬＮ晶体。测试Ｃｕ：ＫＬＮ晶体红外透射谱,研究ＯＨ＾－吸收峰发生红移的原因。以二波耦合光路测量Ｃｕ：ＣＬＮ晶体的光折变擦除曲线,计算擦除时间和光电导,研究Ｃｕ：ＫＬＮ晶体的光折变性能。     

有机光折变聚合物的设计制备研究进展

有机/聚合物光折变材料是一类在信息传输、存储及信息处理等方面有着很大发展潜力的非线性光学材料,文中介绍了有机光折变材料的几种典型应用,综述了目前研究较为深入的几类有机光折变聚合物材料的组成特征和性能特点,并对其近年来材料的设计思想和制备研究进展进行分类表述,分析了材料体系中存在的亟待解决的瓶颈问题。最后对有机光折变聚合物材料的实用性及发展方向进行了展望。     

有机-无机纳米复合光折变材料的研究与进展

在聚合物中掺杂无机半导体纳米粒子作为光敏剂制备的有机-无机纳米复合光折变材料是一种新型的光折变材料.详细介绍了有机-无机纳米复合光折变材料的制备方法、光折变性能及其存在的问题,展望了这类新型材料的潜在优势和发展前景.     

光折变聚合物材料的研究进展

与无机光折变晶体相比,光折变聚合物材料具有非线性光学系数大,响应时间快,成本低廉,制备灵活等优点,成为近代研究的热点。综述了光折变聚合物材料的发展状况,并分析了当前工作所面临的问题及发展前景。     

一种具有荧光猝灭作用的光折变聚合物的合成及表征

采用后重氮偶合反应,得到一种具有荧光猝灭作用的光折变聚合物。采用核磁共振(31P-NMR和1H-NMR)、红外(IR)光谱、凝胶渗透色谱(GPC)、热重分析(TG)和差示扫描量热(DSC)对该聚合物进行表征和分析,以325nm的激发波长对该聚合物进行固体瞬态荧光发射光谱测试。结果表明,该聚合物具有良好的热稳定性,在290℃开始分解,450℃时基本分解完全。聚合物较低的分子量(-Mw=5.36×103g/mol)赋予其较低的玻璃化转变温度(Tg=39℃)。光折变聚合物在分子间形成若干大闭合环路结构,形成的自旋-轨道耦合增加了"系间窜越"的速率,使得聚合物产生迟滞荧光,并且产生荧光猝灭作用。     

掺铜铌酸钾锂晶体光析变效应的研究

在铌酸钾锂 (KLN)晶体中掺进CuO ,采用Czochralski法生长Cu∶KLN晶体。测试Cu∶KLN晶体红外透射谱 ,研究OH- 吸收峰发生红移的原因。以二波耦合光路测量Cu∶KLN晶体的光析变擦除曲线 ,计算擦除时间和光电导 ,研究Cu∶KLN晶体的光折变性能     

PVK／TNF／DR1光折变有机薄膜的真空制备方法

用真空热压、真空“饱和蒸汽溶入”法相结合的方法成功地制备了均匀性及透光性良好的光折变高分子薄膜。由于在真空环境中制备并不使用有机溶剂，所以样品中不存在残留溶剂和微气泡，大大改善了均匀性和耐电压特性，在双光束耦合测试中观察到了明显的光折变效应，且具有很强的电场响应特性，可得到较高的衍射效率，本方法在光学有机薄膜的制备方面有广泛的应用前景。     

Fe2O3的掺杂对TSSG法生长Zn:Fe:LiNbO3 晶体的结构和光折变性能的影响

本文利用TSSG方法生长了不同掺Fe2O3浓度的Zn∶Fe∶LiNbO3晶体,并对晶体进行了红外光谱、紫外光谱、晶格常数和居里温度的测试和分析.利用二波耦合实验测得的写入和擦除曲线,计算了晶体的写入时间常数、擦除时间常数和最大衍射效率.并讨论了Fe2O3的掺杂对材料结构和光折变性能的影响机制.     

Photorefractivity in polymer dissolved liquid crystal composites composed of low-molecular-weight nematic liquid crystals and copolymer comprising mesogenic side groups

This paper describes the photorefractive effect of the liquid crystalline composite materials comprising low-molecular-weight nematic liquid crystals (L-LC), copolymer with mesogenic side groups and a small amount of photosensitizer. Copolymers with four kinds of mesogenic side groups were investigated with respect to the compatibility between the L-LC and the copolymer and the photorefractivity of the composites. Two of them could be miscible with L-LC and the composite exhibited LC phase even though the copolymer itself did not show a LC phase. High gain coefficients (> cm^K1) under the low applied dc electric field (<1V/mm) was observed when the composites showed a mesophase without any macroscopic phase separation.     

Photorefractive effect in triphenylamine-based monolithic molecular glasses with low Tg

A novel series of triphenylamine-based photorefractive molecules M1–M5 with the different push-pull structures were designed and prepared. These molecules can form stable glasses with low glass transition temperature and their optical absorptions as well as photoconductivities at 633 nm increase systematically with increasing acceptor strength and conjugation length. As an unambiguous evidence, the two-beam-coupling experiment was performed to prove the photorefractive effect in each compound with or without an additional sensitizer. Obvious two-beam-coupling effects were obtained for the molecules with good film-forming ability and long-term stability, and among them single-component M1 which has a highly asymmetric structure using both a nitrobenzene and a cyano group as the acceptor showed the best PR performance with a gain coefficient of 52 cm⁻¹ at 0 V μm⁻¹ and 165 cm⁻¹ at 40 V μm⁻¹. Fast response time of 0.025–0.23 s were also obtained at low electric field for these glasses. The correlation of the molecular structure with the PR property was discussed, and a possible explanation for the unique energy transfer observed in M1 and M2 under zero field was proposed.     

氧化还原处理对Fe:LiNbO3晶体光折变性能及热固定效果的影响

在LiNbO3中掺进Fe2O3生长了Fe:LiNbO3晶体,并对晶体进行氧化、还原处理。利用二波耦合的方法,测试了不同还原处理的Fe:LiNbO3,晶体的指数增益系数、衍射效率及响应时间。测试了三种不同处理本热固定后的显影效率,记录了全息先栅的记录、热补偿及离子衰减过程。发现不同氧化还原处理的晶体在光折变性能和热固定效果上有不同的表现。     

Flexible Temperature-Invariant Polymer Dielectrics with Large Bandgap

Flexible dielectrics operable under simultaneous electric and thermal extremes are critical to advanced electronics for ultrahigh densities and/or harsh conditions. However, conventional high-performance polymer dielectrics generally have conjugated aromatic backbones, leading to limited bandgaps and hence high conduction loss and poor energy densities, especially at elevated temperatures. A polyoxafluoronorbornene is reported, which has a key design feature in that it is a polyolefin consisting of repeating units of fairly rigid fused bicyclic structures and alkenes separated by freely rotating single bonds, endowing it with a large bandgap of ≈5 eV and flexibility, while being temperature-invariantly stable over −160 to 160 °C. At 150 °C, the polyoxafluoronorbornene exhibits an electrical conductivity two orders of magnitude lower than the best commercial high-temperature polymers, and features an unprecedented discharged energy density of 5.7 J cm⁻³ far outperforming the best reported flexible dielectrics. The design strategy uncovered in this work reveals a hitherto unexplored space for the design of scalable and efficient polymer dielectrics for electrical power and electronic systems under concurrent harsh electrical and thermal conditions.