Judicious Choice of N-Heterocycles for the Realization of Sky-Blue- to Green-Emitting Carbazolylgold(III) C^C^N Complexes and Their Applications for Organic Light-Emitting Devices

A new class of sky-blue- to green-emitting carbazolylgold(III) C^C^N complexes containing pyrazole or benzimidazole moieties has been successfully designed and synthesized. Through the judicious choice of the N-heterocycles in the cyclometalating ligand and the tailor-made carbazole moieties, maximum photoluminescence quantum yields of 0.52 and 0.39 have been realized in the green- and sky-blue-emitting complexes, respectively. Solution-processed and vacuum-deposited organic light-emitting devices (OLEDs) based on the benzimidazole-containing complexes have been prepared. The sky-blue-emitting device shows an emission peaking at 484 nm with a narrow full-width at half-maximum of 57 nm (2244 cm⁻¹), demonstrating the potential of this class of complexes in the application of OLEDs with high color purity. In addition, high maximum external quantum efficiencies of 12.3 % and a long operational half-lifetime of over 5300 h at 100 cd m⁻² have been achieved in the vacuum-deposited green-emitting devices.     

Synthesis and properties of monodisperse multi‐triarylamine‐substituted oligothiophenes and 4,7‐bis(2′‐oligothienyl)‐2,1,3‐benzothiadiazoles for organic solar cell applications

Two novel series of monodisperse multi‐triarylamine‐substituted oligothiophenes, G ₂ ‐ OT ( n )‐ G ₂ with thiophene unit (n) varying from 6 to 8, and 4,7‐bis(2′‐oligothienyl)‐2,1,3‐benzothiadiazoles G ₂ ‐ OT ( n ) BTD ‐ G ₂ (n = 2, 4, 6) have been synthesized by the Suzuki coupling reactions. With an elongation of alkyl‐substituted oligothiophene core or an incorporation of benzothiadiazole into the central core, the absorption and emission spectra of G ₂ ‐ OT ( n )‐ G ₂ and G ₂ ‐ OT ( n ) BTD ‐ G ₂ series red‐shift substantially with the optical gap reducing to 1.95 eV for G ₂ ‐ OT ( 6 ) BTD ‐ G ₂ . Alkyl‐substitution onto oligothiophene backbone not only improves the solubility of the highly extended dendrimers but also renders coplanarity of the dendritic oligothiophene backbone at the excited state, which results in the enhancement of fluorescence quantum efficiency. The bulk heterojunction solar cells using these newly synthesized dendritic oligothiophenes as a donor material and [6,6]‐phenyl C₆₁‐butyric acid methyl ester (PCBM) as an acceptor material were fabricated and investigated which showed an increase in device performance as compared with those of the lower homologues. On increasing the loading of PCBM from 1.5 to 3 times in the active layer, there was also an enhancement in device performance with power conversion efficiencies of as‐fabricated solar cells increasing from 0.18% to 0.32%. In addition, proper annealing procedure could significantly improve the device performance of the dendrimer‐based photovoltaic cell. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 137–148, 2009     

甲基卤化物的脱卤研究以及在盐溶液(NaCl)环境中通过紫外光分解CH_2I_2制备强酸(英文)

pacc:8240,8250F TheultravioletphotolysisofCH2I2wasstud iedinwater[1-3]andsaltwatersolutionsusing photochemistryandpicosecondtime-resolved resonanceRamanspectroscopy.Photolysisinboth typesenvironmentsproducesmainlyCH2(OH)2andHIproducts.However,photolysisof…     

Control of implantation area in direct-current plasma immersion ion implantation (DC-PIII)

In plasma immersion ion implantation (PIII) of planar samples such as silicon wafers in the PIII-ion-cut as well as separation by plasma implantation of oxygen (SPIMOX) processes, the only important ions are the ones arriving at the top surface. Ions implanted into the other surfaces are, in fact, undesirable as they reduce the efficiency of the power supply and plasma source and give rise to metallic contamination. We have demonstrated direct-current PIII (DC-PIII) by using a grounded grid to separate the vacuum chamber for planar sample implantation. The advantages include lower equipment cost, higher power and time efficiency, larger impact energy, and last but not least, smaller instrument footprint. In this paper, we investigate the control of the implantation area by adjusting the radius of the extraction hole, the distance between the conducting grid and the sample, and the radius of the wafer stage. Theoretical simulation is conducted using particle-in-cell and experiments are also carried out. Our results indicate that the implanted area increases with the radius of the extraction hole and wafer stage, but decreases with a larger distance between the grid and sample. The effects of the extraction hole radius G/sub r/ are the largest, followed by the placement of the sample to the conducting grid H. The wafer stage poses the least influence in this respect, but a proper wafer stage dimension improves the lateral implant dose and incident angle homogeneity. Our simulation and experimental results suggest optimal ratios of these parameters for each wafer size.     

Full emission color tuning in luminogens constructed from tetraphenylethene, benzo-2,1,3-thiadiazole and thiophene building blocks

Full color luminogens are constructed from tetraphenylethene, benzo-2,1,3-thiadiazole and thiophene building blocks. OLED fabricated using one of the luminogens exhibits orange-red electroluminescence with high luminance and efficiencies of 8330 cd m(-2), 6.1 cd A(-1) and 3.1%, respectively.     

A lab-on-chip for biothreat detection using single-molecule DNA mapping

Rapid, specific, and sensitive detection of airborne bacteria, viruses, and toxins is critical for biodefense, yet the diverse nature of the threats poses a challenge for integrated surveillance, as each class of pathogens typically requires different detection strategies. Here, we present a laboratory-on-a-chip microfluidic device (LOC-DLA) that integrates two unique assays for the detection of airborne pathogens: direct linear analysis (DLA) with unsurpassed specificity for bacterial threats and Digital DNA for toxins and viruses. The LOC-DLA device also prepares samples for analysis, incorporating upstream functions for concentrating and fractionating DNA. Both DLA and Digital DNA assays are single molecule detection technologies, therefore the assay sensitivities depend on the throughput of individual molecules. The microfluidic device and its accompanying operation protocols have been heavily optimized to maximize throughput and minimize the loss of analyzable DNA. We present here the design and operation of the LOC-DLA device, demonstrate multiplex detection of rare bacterial targets in the presence of 100-fold excess complex bacterial mixture, and demonstrate detection of picogram quantities of botulinum toxoid.     

Impressive europium red emission induced by two-photon excitation for biological applications

Three triazine-based europium(III) complexes were synthesized that demonstrated strong two-photon induced europium emission with a high two-photon absorption cross-section. The modified triazine ligand of complex 3 initiated over 100% enhancement of the two-photon absorption cross-section (σ(2): 320 GM) when compared with complex 1 (σ(2): 128 GM) in a solution of DMSO. Europium complex 3 is also stable in vitro, and power-dependence curves were obtained in vitro to confirm the two-photon-induced f-f emission in HeLa cells.     

Ideal Structure of the Kauffman and Related Monoids

The generators of the Temperley-Lieb algebra generate a monoid with an appealing geometric representation. It has been much studied, notably by Louis Kauffman. Borisavljevi?, Do?en, and Petri? gave a complete proof of its abstract presentation by generators and relations, and suggested the name “Kauffman monoid”. We bring the theory of semigroups to the study of a certain finite homomorphic image of the Kauffman monoid. We show the homomorphic image (the Jones monoid) to be a combinatorial and regular *-semigroup with linearly ordered ideals. The Kauffman monoid is explicitly described in terms of the Jones monoid and a purely combinatorial numerical function. We use this to describe the ideal structure of the Kauffman monoid and two other of its homomorphic images.     

基于微透镜阵列的DMD芯片投影系统照明优化

分析了照明系统中微透镜阵列的入射光线角度及系统像差对光学利用率的影响,提出了通过修正相关参数来优化照明系统的光学利用率以及照明均匀性的方法。通过改变用于光源聚光的自由曲面透镜的面型来缩小入射角度,从而减小了由于大角度扩散造成的效率损失。并且在微透镜阵列后采用两个球面透镜代替傅里叶透镜作为积分镜片,不仅成本低廉,而且在控制像差方面更为灵活。参数优化后,设计方案的光学利用率可达60.51%,均匀性可达94.24%,验证了理论分析的可行性和有效性。