Nanocrystallized Organic Thin Films as Effective Light Outcoupling Layers for Organic Light-Emitting Diodes

Light outcoupling from organic light-emitting diodes (OLEDs) is essential for developing energy-saving displays and efficient lighting sources. Nanocrystallized organic thin films exhibiting scattering features have been considered as effective light extractors for OLEDs. This paper reviews recent advancements in nanocrystallized thin films and their applications in OLEDs. Due to the advantages of easy preparation and OLED compatibility, nanocrystallized organic thin films can integrate with OLEDs as external or internal light extractors easily. Significant light enhancement has been achieved. The fabrication methods and mechanisms of light enhancement are discussed.     

Monitoring the Microscopic Molecular Mechanisms of Proton Transfer in Acid-base Reactions in Aqueous Solutions

This article provides a review of the authors’ collaborative work on acid-base reactions under conditions allowing direct observation of mechanistic details of the proton transfer within reactive complexes of OH groups and the bases RCOO⁻ (R=organic residues) in diffusion-assisted neutralization reactions by using time-resolved UV/Vis emission and IR absorption spectroscopy. We discuss the considerable insight gained by these experiments and outline the current status of the field.     

香豆素晶体的光二聚——基态非局部化学控制反应的首例

香豆素及其衍生物有重要的生理活性,对此早期已开展了详尽的研究,对它的光化学性能也有些报道。随着实验手段及检测仪器的进步,不断发现有关香豆素光化学的一些新现象和实验结果,并不断修正过去的报道。Hammond等报道香豆素在极性溶剂中(乙醇等),直接光解,生成syn-cis二聚体,在非极性溶剂中,未发现二聚体。但在非极     

激光-分子束-表面散射装置的研制

介绍了自行设计和加工的激光-分子束-表面散射装置，并对超高真空转动密封结构作了详细描述。差分泵浦的超音速分子束对准样品中心，射入超高真空主室。样品架安放在主室中央，四极质谱检测器可绕样品转动，用来测量表面散射分子的平动能及角分布。三个石英窗口作为激光窗口，可用LIF或MPI方法来测量表面散射分子的内能态分布，也可用于研究表面光化学。最后给出了分子束发散角及室温时CH2I2在Ag（110）表面用308um激光光解碎片碘的TOF谱的测量结果。     

Reconfigurable Surfaces Based on Photocontrolled Dynamic Bonds

Photocontrolled surfaces have attracted increasing interest because of their potential applications in lithography, photopatterning, biointerfaces, and microfluidics. Light provides high spatiotemporal resolution to control functions of such surfaces without getting into direct contact. However, conventional photocontrolled surfaces can only be switched between two states (on and off). The development of photocontrolled reconfigurable surfaces that can be switched among multiple states is highly desirable because these surfaces can adapt to rapid environmental changes or different applications. Herein, recent developments of photocontrolled reconfigurable surfaces are reviewed. Specially, reconfigurable surfaces based on photocontrolled reversible reactions including thiol‐quinone methide, disulfide exchange, thiol‐disulfide interconversion, diselenide exchange, and photosubstitution of Ru complexes are highlighted. As a perspective, other photocontrolled dynamic bonds that can be used to construct reconfigurable surfaces are summarized. Remaining challenges in this field are discussed.     

Wavelength‐Dependent Stiffening of Hydrogel Matrices via Redshifted [2+2] Photocycloadditions

Hydrogels with on‐demand tunable mechanical properties within sensitive biological environments are of critical importance for examining cellular responses to cell culture platforms. Herein, the first bio‐orthogonal hydrogel that can be formed and subsequently tuned in its mechanical properties by simply switching different wavelengths of visible light (i.e., 455 and 420 nm) is reported. Specifically, both the initial hydrogelation and the tuning of the mechanical properties can be fully decoupled and selectively initiated by different colors of light. Sparing the need for any catalysts, the development of such a dual wavelength selective hydrogel for biological applications spans four levels: First, the development of the until today most redshifted photocycloaddition to allow for the selective initiation of only one photoreaction; second, the investigation of its wavelength‐dependent ligation efficiency; third, translation of the ligation chemistry into a hydrogelator, and fourth, establishing a biocompatible hydrogel platform for applications in biomaterials engineering including detachment of fibroblasts from 2D culture areas or primary 3D culture of human mesenchymal stem cells. The introduced platform technology enables the fabrication of a hydrogel of predefined mechanical properties exclusively with visible light.     

Comparison of two approaches to grafting hydrophilic polymer chains onto polysulfone films

To reduce the surface protein adsorption of polysulfone (PSf) film, we improved the hydrophilicity of this film by photochemical grafting of methoxypoly (ethylene glycol) (MPEG) derivatives on its surface. Grafting was achieved with both the simultaneous method and the sequential method. Surface analysis of the grafted film by X‐ray photoelectron spectroscopy (XPS) revealed that the PEG chains had successfully grafted onto the surface of the film. The grafting efficiencies by simultaneous and sequential methods were 20.8% and 10.2%, respectively. With an atomic force microscope (AFM), the surface topography of PEG‐grafted films by these two methods was compared. Static water contact angle measurement indicated that the surface hydrophilicity of the film had been improved. Protein adsorption measurement showed that the surface protein adsorption of the modified film was significantly reduced compared with that of the unmodified PSf film. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3818–3826, 2007     

碳掺杂ZnO薄膜及可见光催化氮合成氨

采用磁控溅射双靶共溅射方法，在玻璃表面成功制备了高催化活性的碳掺杂ZnO薄膜。通过X射线衍射仪、高倍透射电镜、X射线光电子能谱仪等表征了碳掺杂ZnO薄膜，并在可见光催化氮合成氨实验中评价了薄膜的催化剂性能。结果表明碳掺杂的ZnO薄膜中存在碳量子点，尺寸为4nm，晶面间距0.21nm，薄膜可以吸收可见光。同时ZnO晶格中的碳提高了ZnO导带的位置，增强了激发电子的还原能力。当碳掺杂量为1.03%时，氨氮产量为5.15×10^–4mol/(h·cm²)。利用反胶束蚀刻法又成功地在玻璃表面蚀刻出了微米坑，坑口径为0.5～2μm，坑深为100～500nm。与平面玻璃表面上的薄膜比较，在光催化氮合成氨实验中微米坑玻璃表面上薄膜的氨氮产量提高了约1.4倍，膜基结合力提高了2倍多。结合薄膜的能带结构图讨论了碳掺杂ZnO薄膜的光催化机理。