微腔对有机发光的影响的研究

利用介质膜反射镜 ,在光泵浦有机小分子薄膜微腔的研究中 ,观察到了谱线窄化、峰值强度增强、方向性集中于腔轴、控制发射波长和荧光寿命的缩短等一系列腔效应。其中用软膜反射镜 ,消除了镀制过程中热辐射对有机发光材料的影响 ,谱线半宽最窄达3.4nm,窄化了 2 5倍 ;峰值强度最大增强了 1 6倍。     

微腔对有机发光的影响的研究

利用介质膜反射镜,在光泵浦有机小分子薄膜微腔的研究中,观察到了谱线窄化、峰值强度增强、方向性集中于腔轴、控制发射波长和荧光寿命的缩短等一系列腔效应.其中用软膜反射镜,消除了镀制过程中热辐射对有机发光材料的影响,谱线半宽最窄达3.4nm,窄化了25倍;峰值强度最大增强了16倍.     

微腔对摩擦副摩擦系数的影响机理研究

将微腔模型引入摩擦副摩擦研究,通过建立微腔的气体-压强模型,分析了摩擦副微腔对摩擦的影响机理.并尝试用所建立的模型解释载荷、摩擦副相对运动速度、环境气压、静止接触时间对摩擦系数的影响.     

有机发光显示器件的研究进展

有机发光显示器件的自主发光、低功耗、宽视角和快响应速度等优点,使之成为新一代平板显示器件的有力竞争者。在阐述有机发光材料和有机显示面板研究进展的基础上,重点介绍了有机显示器件中两种较为成熟的驱动电路及其优缺点,论文同时还对上述核心技术目前存在的问题进行了简要的分析。最后讨论了有机显示实现大规模产业化所面临的机遇和挑战。     

最小的有机发光装置

美国Comell大学的科学家们制造出了只有病毒或最小的细菌大小的世界上最小的“纳米光源”。他们的结果发表在《Nan Letter》上。[第一段]     

首块有源选址有机发光显示器基板

南开大学与香港科技大学合作开发的一项有机发光显示技术成果取得重大突破，近日被教育部专家组鉴定为罕见的“国际首创”水平，与之相关的5项技术达到国际先进水平。     

近红外有机发光材料研究取得进展为设计近红外有机电致发光材料提供了新思路

我国科学家与国外科学家通力合作，在近红外有机电致发光材料方面取得重要进展．相关结果近期陆续发表在国外学术期刊《材料化学》和《先进材料》上。该项工作被认为为将来设计近红外有机电致发光材料提供了新的思路，对有机光电子学和光通讯应用的研究与发展具有重要的指导意义。     

有源选址有机发光显示器基板

南开大学与香港科技大学合作开发的一项有机发光显示技术成果取得重大突破，不久前，通过了教育部专家组鉴定，该成果达到国际先进水平。     

Fiber optic light collection system for scanning-tunneling-microscope-induced light emission

We report a compact light collection scheme suitable for retrofitting a scanning tunneling microscope (STM) for STM-induced light emission experiments. The approach uses a pair of optical fibers with large core diameters and high numerical apertures to maximize light collection efficiency and to moderate the mechanical precision required for alignment. Bench tests indicate that efficiency reduction is almost entirely due to reflective losses at the fiber ends, while losses due to fiber misalignment have virtually been eliminated. Photon-map imaging with nanometer features is demonstrated on a stepped Au(111) surface with signal rates exceeding 10(4) counts/s.     

Near-field effects in single molecule emission

We present the first experimental proof of the influence of a nearby nano-sized metal object on the angular photon emission by a single molecule. A novel angular sensitive detection scheme is implemented in an existing near-field scanning optical microscope (NSOM). The positioning accuracy (∼1 nm) of the NSOM allows a systematic investigation of the intensity ratio between two different half-spaces as a function of the position of the metal–glass interfaces of the probe with respect to the single emitter. The observed effects are shown to be particularly strong for molecules that are excited mainly below the rims of the aperture. An excellent agreement is found between experiments and numerical simulations for these molecules. The observed angular redistribution of the angular emission of a single molecule could explain the alteration of the emission polarization observed for certain molecules in earlier experiments (Veerman et al. (1999) J. Microsc. 194 , 477–482).     

Safe fabrication of sharp gold tips for light emission in scanning tunnelling microscopy

Gold is the optimal tip metal for light emission in scanning tunnelling microscopy (LESTM) under ambient conditions. Sharp Au-tips of 10 nm radius were produced reliably using a safe, two-step etching method in 20% (w/w) CaCl₂ solution. Previous CaCl₂-based methods have tended to produce blunter tips, while other etching techniques that do produce sharp Au-tips, do so with the use of toxic or hazardous electrolytes. The tips are characterised using scanning electron microscopy and their efficacy in LESTM is evidenced by high-resolution, simultaneous topographic and photon mapping of Au(1 1 1)- and polycrystalline Au-surfaces. Spectra of the optical emission exhibit only one or two peaks with etched tips in contrast to the more complex spectra typical of cut tips; this feature, together with the highly symmetric geometry of the tips, facilitates a definitive analysis of the light emission process.     

Calibration and standardization of the emission light path of confocal microscopes

Recently, there has been a large expansion in the usage of optical microscopes for obtaining quantitative information from biological samples in order to determine fundamental biological information such as molecular kinetics and interaction, and heterogeneity within cell populations. Consequently, we built a highly stable, uniform, isotropically emitting and convenient‐to‐use light source, and designed image analysis procedures for calibrating the emission light path of optical microscopes. We used the source and procedures to analyse the quantitative imaging properties of a widely used model of laser scanning confocal microscope. Results showed that the overall performance was as high as could be expected given the inherent limitations of the optical components and photomultiplier tubes. We observed that the photon detection efficiency did not vary with photomultiplier tube gain and that the highest dynamic range was achieved with relatively low gain and 12‐bit digitization. Practical applications of the light source for checking the transmission of optical components in the emission light path are presented.     

室温发光硅基法布里-珀罗微腔的结构设计

提出了一种新型法布里-珀罗(F-P)微腔结构.它采用PECVD方法制备的硅/氮氧化硅结构作为微腔中的布拉格反射器,非晶碳化硅薄膜作为中间光发射层,通过对一维方向光子的限制,使发光层荧光强度增强,谱线变窄.通过调节发光层和反射器膜厚及折射率,可以精确控制发光峰位.因此,该结构可望实现全硅基材料的强室温蓝光发射.     

Noise effects and filtering in controlled light exposure microscopy

Phototoxicity and photobleaching are major limitations of fluorescence live-cell microscopy. A straightforward way to limit phototoxicity and photobleaching is reduction of the excitation light dose, but this causes loss of image quality. In confocal fluorescence microscopy, the field of view is illuminated uniformly whereas in controlled light exposure microscopy, illumination is controlled per pixel on the basis of two illumination strategies. The controlled light exposure microscopy foreground strategy discriminates between bright and weak foreground. Bright foreground pixels are illuminated with a reduced light dose resulting in limited excitation of fluorophores and consequently limited phototoxicity and photobleaching. The controlled light exposure microscopy background strategy discriminates between foreground and background. Pixels that are judged to be background are also illuminated with a reduced light dose. The latter illumination strategy may introduce artefacts due to the stochastic character of photon flow. These artefacts are visible as erratic 'darker pixels' in the foreground with a lower pixel value than the neighbouring pixels. This paper describes a special adaptive image processing filter that detects and corrects most of the 'darker pixels'. It opens the possibility to use controlled light exposure microscopy even in high noise (low signal to noise ratio) imaging to further reduce phototoxicity and photobleaching.     

Investigation of elastic emission machining process: lubrication effects

This paper studies the lubrication effects on the machining rate of the elastic emission machining (EEM) process. Several experiments are conducted to reveal the correlation between the machining rate and lubricating conditions. It is shown that the machining rate is highly affected by the lubricating conditions of slurry at the spot between the tool and the work surface. Particularly, it is shown that the machining rate has a positive relationship with the shear stress of lubrication film under various lubricating conditions. The study postulates that shear stress plays an important role of removing the bound particle and atoms. Thus, when shear stress is large, there may exist a high probability of having a successful removing action, and the machinin rate is high.