Structures and spectroscopic properties of nonperipherally and peripherally substituted metal-free phthalocyanines: a substitution effect study based on density functional theory calculations

The molecular structures, molecular orbitals, atomic charges, electronic absorption spectra, and infrared (IR) and Raman spectra of a series of substituted metal-free phthalocyanine compounds with four (1, 3, 5, 7) or eight (2, 4, 6, 8) methoxyl (1, 2, 5, 6) or methylthio groups (3, 4, 7, 8) on the nonperipheral (1-4) or peripheral positions (5-8) of the phthalocyanine ring are studied by density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. The calculated structural parameters and simulated electronic absorption and IR spectra are compared with the X-ray crystallography structures and the experimentally observed electronic absorption and IR spectra of the similar molecules, and good agreement between the calculated and experimental results is found. The substitution of the methoxyl or methylthio groups at the nonperipheral positions of the phthalocyanine ring has obvious effects on the molecular structure and spectroscopic properties of the metal-free phthalocyanine. Nonperipheral substitution has a more significant influence than peripheral substitution. The substitution effect increases with an increase in the number of substituents. The methylthio group shows more significant influence than the methoxyl group, despite the stronger electron-donating property of the methoxyl group than the methylthio group. The octa-methylthio-substituted metal-free phthalocyanine compounds have nonplanar structures whose low-lying occupied molecular orbitals and electronic absorption spectra are significantly changed by the substituents. The present systematical study will be helpful for understanding the relationship between structures and properties in phthalocyanine compounds and designing phthalocyanines with typical properties.     

Comparison of structural and photoluminescence properties of ZnO thin films grown by pulsed laser deposition and ultrasonic spray pyrolysis

ZnO thin films have been deposited by pulsed laser deposition (PLD) and ultrasonic spray pyrolysis (USP) method, respectively. X-ray diffraction and transmission electron microscopy characterizations indicate that ZnO film grown by PLD exhibits better crystallinity than that grown by USP. Photoluminescence spectra show that the near-band edge ultraviolet emission of film grown by PLD is narrower and shifts to higher energy, compared with that of film grown by USP. In the visible range, ZnO film grown by PLD exhibits four local level emission centered at 470 nm, 486 nm, 544 nm, and 613 nm, respectively, while the film grown by USP only presents a weak broad band emission centered at 502 nm. Hall measurement shows higher carrier density and lower hall mobility in ZnO film grown by PLD than that in film grown by USP. The higher density of intrinsic defects as well as higher crystallintiy is considered to account for the difference of photoluminescence in ZnO film grown by PLD with that in film grown by USP.     

实验室装备及实验室信息管理系统

本文回顾了CISILE 2008第六届中国科学仪器及实验室装备展览会,并对通用实验室设备、制药等行业相关的实验室设备、实验室信息管理系统LIMS等技术和展品的最新情况进行了概述。     

Interfacial assembly of sandwich mixed (Phthalocyaninato)(Porphyrinato) rare earth triple-decker complexes: Effect of in situ coordination

Interfacial assembly of sandwich mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes [(Pc)Eu(Pc)Eu(TPyP)] (1) and [(TPyP)Sm(Pc)Sm(TPyP)] (2) (Pc = phthalocyaninate, TPyP = meso-tetrakis(4-pyridyl)porphyrinate) has been comparatively studied at the air/pure water and the air/CdCl₂ aqueous solution subphase interfaces. Surface pressure-area isotherms revealed the remarkable increase of limiting mean molecular area of the triple-deckers with the presence of Cd²⁺, suggesting the occurrence of in situ interfacial coordination. The formation of coordination bonds between the pyridyl groups of TPyP macrocycles in the triple-deckers and Cd²⁺ ions from the subphase was further supported by FT-IR spectroscopic data. Electronic absorption measurements showed the formation of J-aggregates of the triple-decker molecules in the interfacial assembled films.     

A highly efficient OLED based on terbium complexes

A neutral ligand 9-(4-tert-butylphenyl)-3,6-bis(diphenylphosphineoxide)-carbazole (DPPOC) and its complex Tb(PMIP)₃DPPOC (A, where PMIP stands for 1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone) were synthesized. DPPOC has a suitable lowest triplet energy level (24,691 cm^?1) for the sensitization of Tb(III) (⁵D₄: 20,400 cm^?1) and a significantly higher thermal stability (glass transition temperature 137 °C) compared with the familiar ligand triphenylphosphine oxide (TPPO). Experiments revealed that the emission layer of the Tb(PMIP)₃DPPOC film could be prepared by vacuum co-deposition of the complex Tb(PMIP)₃(H₂O)₂ (B) and DPPOC (molar ratio = 1:1). The electroluminescent (EL) device ITO/N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-diphenyl-4,4′-diamine (NPB; 10 nm)/Tb(PMIP)₃ (20 nm)/co-deposited Tb(PMIP)₃DPPOC (30 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP; 10 nm)/tris(8-hydroxyquinoline) (AlQ; 20 nm)/Mg_0.9Ag_0.1 (200 nm)/Ag (80 nm) exhibited pure emission from terbium ions, even at the highest current density. The highest efficiency obtained was 16.1 lm W^?1, 36.0 cd A^?1 at 6 V. At a practical brightness of 119 cd m^?2 (11 V) the efficiency remained above 4.5 lm W^?1, 15.7 cd A^?1. These values are a significant improvement over the previously reported Tb(PMIP)₃(TPPO)₂ (C).     

A new technique for boosting efficiency of silicon solar cells

A new type of photovoltaic system with higher generation power density has been studied in detail. The feature of the system is a V-shaped module (VSM) with two tilted monocrystalline solar cells. Compared to solar cells in a flat orientation, the VSM enhances external quantum efficiency and leads to an increase of 31% in power conversion efficiency. Due to the VSM technique, short-circuit current density was raised from 24.94 to 33.7 mA/cm², but both fill factor and open-circuit voltage were approximately unchanged. For the VSM similar results (about 30% increase) were obtained for solar cells fabricated by using mono-crystalline silicon wafers with only conventional background impurities.     

选择重传ARQ重排序方法研究

分析了现有的重排序机制,提出了基于PFR方案的分级PFR方案H—PFR,通过保存正确的重排序数据帧,在进行TCP超时重传时,能立刻在本地完成正确排序的数据帧向高层的转发,缩短了延迟时间,节省了信道资源,提高了无线TCP的传输性能。     

可视通信系统开发调试环境的研究

提出并实现了基于 Ｔ Ｃ Ｐ／ Ｉ Ｐ 的 Ｈ３２ Ｘ 系列 Ｖｉｄｅｏ Ｐｈｏｎｅ 局域网仿真开发环境。给出了系统结构,讨论了开发环境的协议仿真模型、数据回路设计、数据流管理、通信仿真、在线监测、错误报告与分析、数据分析统计与性能指标测试等问题。     

分析MES在小批量电子产品生产管理中的应用

MES是生产管理系统的核心,是管理信息系统和生产企业过程自动化系统之间的桥梁。制造执行系统是当前企业应用和信息化研究的热点之一,设计针对电子制造企业的制造执行系统,体现了电子制造行业对制造执行系统的功能要求。本文阐述了制造执行系统在这种生产环境下的管理应用,介绍了小批量生产环境下电子产品科研生产管理中所存在的问题。     

A novel attributes anonymity scheme in continuous query

In location-based service (LBS), the un-trusted LBS server can preserve lots of information about the user. Then the information can be used as background knowledge and initiated the inference attack to get user’s privacy. Among the background knowledge, the profile attribute of users is the especial one. The attribute can be used to correlate the real location in uncertain location set in both of the snapshot and continuous query, and then the location privacy of users will be revealed. In most of the existing scheme, the author usually assumes a trusted third party (TTP) to achieve the profile anonymity. However, as the TTP disposes all anonymous procedure for each user, it will become the center of attacks and the bottleneck of the query service. Furthermore, the TTP may be curious about user’s privacy just because of the commercial consideration. In order to deal with the inference attack and remedy the drawback of TTP scheme, we propose a similar attributes anonymous scheme which based on the CP-ABE, and with the help of center server and collaborative users, our scheme can resist the inference attack as well as the privacy detection of any entity in the service of query. At last, security analysis and experimental results further verify the effectiveness of our scheme in privacy protection as well as efficiency of the algorithm execution.