分散染料晶型生成热与晶型热稳定性的研究

本文用燃烧热法鉴别分散染料深蓝H-GL不同晶型的热稳定性。测定了分散染料深蓝H-GL的不同晶型,α-、β-和无定形的生成热,分别为-657±4.3,-638±7.3、-565±5.3千焦/摩尔。确定了它们稳定性的序列:α->β->无定形。     

黑曲霉菌丝球对直接耐晒翠蓝FBL的脱色特性

探讨黑曲霉(Aspergillus niger)菌丝球的生长特性,以及染料种类对其脱色特性的影响.以直接耐晒翠蓝FBL为处理对象,考察染料初始质量浓度、曲霉孢子投加量、pH值、无机盐质量分数、温度、C源和N源对黑曲霉的脱色性能的影响.结果表明,黑曲霉对多种染料有很好的去除效果.对直接耐晒翠蓝FBL的最佳脱色条件是:染料初始质量浓度低于100 mg·L-1、黑曲霉孢子投加量为2.5×104个·mL-1、染料培养基pH值为6、Nacl质量分数低于5%,培养温度在30～40℃之间,并需适量补充C源、N源.     

Transflective BPIII mode with no internal reflector

A transflective device without reflector using room temperature blue phase III (BPIII) material is demonstrated in this study. In this device, the coupling of an induced birefringence and field-induced BP, relating the ordered orientation of the double-helix cylinders, causes the reflection and transmission. Compared with other reported transflective liquid crystal devices, the BPIII device shown here does not need any type of internal reflector. Well-matched voltage-dependent transmittance and reflectance curves can be obtained easily without considering the cell gap and incident wavelength. The total response time is less than 2 ms, which is also independent of the cell gap. The experimental results exhibit a simple way to get a transflective device with good ability based on the electro-optical properties of BPIII.     

Hydrogen bond network-stabilisation of blue phases by addition of a chiral N-(10-hydroxydecyl)succinimide derivative and alkane diols

Blue phases (BPs) obtained by doping a commercially available liquid crystalline compound (4-butyl-N-(4-ethoxybenzylidene)aniline (EBBA)) with (2R,3R)-2,3-bis(4-octyloxyphenylbenzoyloxy)-N-(hydroxydecyl)succinimide (1) were highly stabilised by the addition of a small amount of alkane diols. Especially, addition of only 0.5 mol% of octane-1,8-diol increased the BP–Iso transition temperature by 10 K and widened the BP temperature range up to 35 K. A model stabilisation mechanism based on the construction of a hydrogen bond network in each disclination zone in BPs was proposed.     

Triphenylamine and quinoline-containing polyfluorene for blue light-emitting diodes

A novel blue light-emitting polyfluorene-based copolymer PTHD containing electron-rich triphenylamine and electron-poor phenylquinoline side chains in the C-9 position of fluorene unit is described. By comparison of the solution and thin film photoluminescence (PL) spectra of PTHD, a considerable red-shift of Δλ = 10-15 nm was observed in the thin film PL spectrum. The emission intensity of the shoulder peak appeared in dilute solution was also significantly enhanced in the thin film. In contrast to the reference polymer poly{[9,9-dihexylfluorene]-alt-[9,9-di(2,4-diphenylquinoline)fluorene]}, PTHD exhibits higher HOMO energy level, and higher maximum brightness with the PLED device configuration of ITO/PEDOT:PSS/polymer_70% + PBD_30%/TPBI/LiF/Al.     

聚芴类半导体光谱稳定性

有机半导体的物理和化学性质直接影响其光电器件的性能, 这为物理化学提出了新的研究内容与挑战. 其中, 聚芴类蓝光二极管的光谱稳定性及低能发射带(LEEB)的起源问题是国际上近十年的热点问题之一. 本文系统概述了低能发射带的现象、表征方法以及可能的形成机理, 包括链间作用导致的激基缔合物发射、器件制备或降解过程形成的芴酮缺陷发射、芴酮聚集态发射以及聚芴端羟基界面氧化导致的绿光发射. 本文综述各种物理掺杂和界面调控改善聚芴类二极管蓝光稳定性的策略, 着重论述非平面基团的空间位阻、分子构象与链的拓扑结构以及引入抗氧化受阻胺光稳定剂来提高其光谱稳定性策略.     

有机膨润土负载ZnO/TiO2光降解催化剂的研制及性能

以六水硝酸锌、酞酸丁酯和有机膨润土为原料,采用沉淀法制备ZnO/TiO2膨润土复合光催化材料,用IR和XRD对光催化剂的组织构造和微观结构进行表征,实验了光催化剂对亚甲基蓝废水的降解性能。结果表明：ZnO/TiO2成功负载于膨润土片层表面,ZnO的含量为有机膨润土的8%,反应温度为70℃,焙烧温度为420℃,催化剂用量为12mg/L时,亚甲基蓝废水的降解率可达97%以上。     

Electroluminescence of colloidal ZnSe quantum dots

The article reports a green chemical synthesis of colloidal ZnSe quantum dots at a moderate temperature. The prepared colloid sample is characterised by UV-vis absorption spectroscopy and transmission electron microscopy. UV-vis spectroscopy reveals as-expected blue-shift with strong absorption edge at 400 nm and micrographs show a non-uniform size distribution of ZnSe quantum dots in the range 1-4 nm. Further, photoluminescence and electroluminescence spectroscopies are carried out to study optical emission. Each of the spectroscopies reveals two emission peaks, indicating band-to-band transition and defect related transition. From the luminescence studies, it can be inferred that the recombination of electrons and holes resulting from interband transition causes violet emission and the recombination of a photon generated hole with a charged state of Zn-vacancy gives blue emission. Meanwhile electroluminescence study suggests the application of ZnSe quantum dots as an efficient light emitting device with the advantage of colour tuning (violet-blue-violet).     

High power efficiency in single layer blue phosphorescent organic light-emitting diodes

High efficiency single layer blue phosphorescent organic light-emitting diodes (PHOLEDs) without any charge transport layer were developed. A mixed host of spirobifluorene based phosphine oxide (SPPO13) and 1, 1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) was used as the host in the emitting layer. A high maximum external quantum efficiency of 15.8% and a quantum efficiency of 8.6% at 1000 cd/m² were achieved in the single-layer blue PHOLEDs without any charge transport layer. The maximum power efficiency and power efficiency at 1000 cd/m² were 31.4 and 16.9 lm/W, respectively.     

Luminescence efficiencies of self- and Tm activated CaWO4 under vacuum ultraviolet radiation excitation

Luminescence efficiency of self-activated CaWO₄ under 147 nm vacuum ultraviolet (VUV) radiation excitation is about 90% of that of BaMgAl₁₀O₁₇:Eu²⁺ (BAM), the commercial blue plasma display panel (PDP) phosphor. However, the color purity and the particle size of the former needs substantial modification before it can be considered for application in PDP. CaWO₄:Tm exhibits Tm³⁺ emission peaks in the blue region due to energy transfer from WO₄ to Tm³⁺ ions but the overall emission intensity under 147 nm excitation is reduced when compared to that of CaWO₄.