叶绿素及其Cu、Zn衍生物的伪装性能研究

研究了类叶绿素活性颜料在伪装应用中的光谱性能及光稳定性问题。从绿色植被的色素着手,分析了叶绿素的性质及影响其降解的原因,用Cu2+、Zn2+金属离子替代天然叶绿素中的Mg2+,制备了叶绿素衍生物,并通过光谱特性和光稳定性对叶绿素衍生物的特性进行了比较分析。研究结果表明,从光谱性能和稳定性两方面综合考虑,Cu叶绿素更适合作为叶绿素修饰目标来提高颜料的稳定性,从而为新型光学伪装涂料的制备提供材料基础。     

Effect of Natural Deep Eutectic Solvents on trans-Resveratrol Photo-Chemical Induced Isomerization and 2,4,6-Trihydroxyphenanthrene Electro-Cyclic Formation

trans-Resveratrol is a natural bioactive compound with well-recognized health promoting effects. When exposed to UV light, this compound can undergo a photochemically induced trans/cis isomerization and a 6π electrochemical cyclization with the subsequent formation of 2,4,6-trihydroxyphenanthrene (THP). THP is a potentially harmful compound which can exert genotoxic effects. In this work we improved the chromatographic separation and determination of the two resveratrol isomers and of THP by using a non-commercial pentafluorophenyl stationary phase. We assessed the effect of natural deep eutectic solvents (NaDES) as possible photo-protective agents by evaluating cis-resveratrol isomer and THP formation under different UV-light exposure conditions with the aim of enhancing resveratrol photostability and inhibiting THP production. Our results demonstrate a marked photoprotective effect exerted by glycerol-containing NaDES, and in particular by proline/glycerol NaDES, which exerts a strong inhibitory effect on the photochemical isomerization of resveratrol and significantly limits the formation of the toxic derivative THP. Considering the presence of resveratrol in various commercial products, these results are of note in view of the potential genotoxic risk associated with its photochemical degradation products and in view of the need for the development of green, eco-sustainable and biocompatible resveratrol photo-stable formulations.     

两例相同混合配体构筑的Pb(Ⅱ)/Ag(I)配位聚合物及其荧光性质

多齿配体2-咪唑乙酸(Hima)、4,4'-连吡啶分别与金属盐Pb(NO3)2和AgNO3反应,得到[Pb2(4,4'-bipy)(ima)(NO3)3]n(1,3D framework)和[Ag4(4,4'-bipy)3(ima)2(NO3)2(H2O)2]n(2,3D framework)两个配位聚合物.根据配位聚...     

适宜于光聚合过程应用的荧光探针研究

研究了两种探针化合物在安息香醚引发烯类单体光聚合反应中的应用.发现在光聚合反应中,不同的探针化合物有着不同的光谱响应特征和溶致变色行为,显然,这对探针的灵敏度会带来影响.实验结果表明:探针化合物在光聚合反应中能否应用,其光照稳定性起着关键作用.本工作推荐了一种适宜在烯类单体光聚合反应中应用的探针化合物.     

Negative Dielectric Anisotropy Liquid Crystal with Improved Photo-Stability,Anti-Flicker,and Transmittance for 8K Display Applications

Video systems such as 8K displays can provide a strong sense of presence and reality due to their extremely high resolution and wide field of view. However, high-resolution displays generally suffer from reduced transmittance, which requires the use of liquid crystals with high transmittance and high stability. In this study, negative dielectric anisotropy liquid crystal compositions with excellent photo-stability, anti-flicker capability, and high transmittance are developed, showing potential for 8K display applications. The stability of different types of negative dielectric anisotropy liquid crystal compounds is assessed under light, and the high photo-stability compounds are obtained. In addition, it is demonstrated that the flicker can be optimized from −17.6 to −47.0 by removing the compounds with a higher ion content and a larger deformation number and adding the compounds with a smaller deformation number in the negative dielectric anisotropy liquid crystal compositions. Combining with the evaluation of the factors affecting the response time, the negative dielectric anisotropy liquid crystal mixed H is designed with improved stability and flicker; thus, the response time was decreased to 9.5 ms, and the optical transmittance was 5.5% higher than that of MAT-09-1284 (for normal) and 3.1% higher than that of BY19-J01A (for 4K).     

核/壳结构CdSe/CdS纳米晶的制备及其光稳定性

在水溶液中制备了CdSe纳米晶和核/壳结构CdSe/CdS纳米晶,用X射线粉末衍射和X射线光电子能谱对其进行了表征.比较了新制样品与放置30天后样品的吸收光谱和发射光谱,结果表明核/壳结构CdSe/CdS纳米晶具有更好的光学稳定性,可望在光致发光器件和生物荧光标记上得到应用.     

八羟基喹啉铝取代钙作为电子传输层对聚合物太阳电池光稳定性的影响

通过选择高效窄带隙聚合物给体材料PTB7与电子受体材料PC71BM作为聚合物太阳电池的活性层,采用Glass/ITO/poly(ethylenedioxythiophene)∶polystyrene sulphonate(PEDOT∶PSS)/PTB7∶PC71BM/electron extraction layer(EEL)/Al的器件结构研究了不同EEL对器件性能及光稳定性的影响。通过采用小分子有机材料Alq3与低功函数碱金属Ca作为EEL,发现由于Ca的活泼金属特性及不稳定性,以Ca作为EEL的聚合物太阳电池的初始效率在3d之后就下降了60%;而以Alq3作为EEL的器件在空气中放置一个月之后其初始效率仅下降30%。此外,以Alq3作为EEL的器件光伏效率完全比得上传统器件中以Ca作为EEL的光伏器件。研究结果表明,Alq3是一种潜在的长寿命聚合物太阳电池的EEL材料。     

Improved efficiency and photo-stability of methylamine-free perovskite solar cells via cadmium doping

Although perovskite solar cells containing methylamine cation can show high power conversion efficiency, stability is a concern. Here, methylamine-free perovskite material Cs_xFA_1–xPbI₃ was synthesized by a one-step method. In addition, we incorporated smaller cadmium ions into mixed perovskite lattice to partially replace Pb ions to address the excessive internal strain in perovskite structure. We have found that the introduction of Cd can improve the crystallinity and the charge carrier lifetime of perovskite films. Consequently, a power conversion efficiency as high as 20.59% was achieved. More importantly, the devices retained 94% of their initial efficiency under 1200 h of continuous illumination.     

2018年2期电子期刊

光诱导功能退化是胶体量子点在应用中面临的主要挑战之一,本文针对这一问题研究了使用磁控溅射沉积SiO₂薄膜形成钝化层来提高CdSe/ZnS量子点发光稳定性的方法。首先,通过三正辛基膦辅助连续离子层吸附反应方法合成了615 nm发光的红色CdSe/ZnS量子点。然后将量子点旋涂在SiO₂/Si基片上,再通过磁控溅射方法在量子点上沉积了厚度为20 nm的SiO₂薄膜作为钝化层。使用连续波激光光源分别在空气气氛和真空条件下照射样品,研究了经过不同照射时间后钝化和未钝化量子点的稳态光致发光光谱。结果表明,随着照射时间的延长,没有SiO₂钝化的量子点的PL强度显著降低、PL峰值发生蓝移、FWHM不断增大。对比研究发现,由于SiO₂薄膜能够阻挡空气中的水和氧,减缓了量子点表面的光诱导氧化现象,因此显著提高了CdSe/ZnS量子点的稳定性。     

胶乳法氯化天然橡胶的光、热氧稳定性能

胶乳法氯化天然橡胶CNR经紫外光老化、热氧老化实验、化学分析、紫外光谱分析和热分析,结果表明：产品较溶液法光稳定性稍差,加入0．4％(质量百分比)的紫外线吸收剂AUI(二苯甲酮类)、AUII(苯并三唑类)和极少量的抗氧剂,可显著提高抗热氧老化性能。最佳配方为0．2％／0．5％(质量百分比)AOI(酚类抗氧剂)与AOIH(亚磷酸酯类抗氧剂)并用,或加入0．2％(质量百分比)的AOI。