SYNTHESIS AND PHOTOELECTRIC PROPERTIES OF PERYLENE RED PIGMENTS

A series of N, N′ dialkyl (and aryl) perylene 3,4:9, 10 bis (dicarboximide) compounds were prepared and purified, and their photoelectric properties as organic photoconductors were explored. It is found that N, N′ dimethyl perylene 3,4:9, 10 bis (dicarboximide) and perylene 3,4:9,10 tetracarboxylic acid bisbenzimidazole show excellent photoconductivities, their charge acceptance reaches 700 V and 485 V, and the photosensitivity is 45 lx·s and 10 lx·s with dark decays 70 and 60 V/s respectively. The introduction of chlorine atoms can improve their photoelectric properties. SEM analyses also show that the dispersion of pigment in OPC could affect its photosensitivity.

Endoscopic vs external dacryocystorhinostomy-comparison from the patients' aspect

·AIM: To compare the success and complication rates,duration of surgeries and clinical comfort after endoscopic dacryocystorhinostomy(END-DCR) or external dacryocysto-rhinostomy(EXT-DCR).·METHODS: Fifty patients who underwent EXT- or END-DCR between January 2010-2012 were involved in the study. A questionnaire was applied to patients preoperatively, and postoperatively. Subjective success was defined by absence of epiphora, objective success by a normal nasolacrimal lavage and a positive functional endoscopic dye test(FEDT). Postoperative pain and cosmetic result of surgery were interpreted by the patients, who were also asked whether they would offer this surgery to a friend or would prefer this surgery once more if necessary.·RESULTS: Twenty-five patients underwent END-DCR and 25 underwent EXT-DCR. Mean duration of surgeries were 35 min both for EXT-DCR(30-50) and END-DCR(35-50)(P =0.778). Intraoperative bleeding were documented in 48% of EXT-DCR and 4% of END-DCR cases(P 【0.001). In total 96% of EXT-DCR and 100% of END-DCR patients had subjective success. Objective success was 100% in each group. There was no significant difference between the epiphora scorings and FDDT results in postoperative visits among the groups.END-DCR group reported less pain in first week and month(P 【0.05, P 【0.05). More patients in END-DCR group were happy with the cosmetic result in first week and month(P 【0.001, P 【0.001). More patients in END-DCR group offered this surgery to a friend(P 【0.001). All patients in END-DCR group preferred this surgery once more if necessary, only 48% in EXT-DCR preferred the same method(P 【0.001).·CONCLUSION: Although both END- and EXT-DCRs provide satisfactory outcomes with similar objective andsubjective success rates, we demonstrated that the endonasal approach caused significantly less pain in early postoperative period than the external approach.Clinical comfort defined by the patients was quite higher in END-DCR group, in which patients mainly were pleased to encounter a sutureless surgical area.

Photoelectric Property of Polyaniline Doped with Organic Sulphonic Acid

Photoelectric property of polyaniline doped with dodecyl-benzene sulphonic acid (DBSA) is studied. The result shows that the concentration of carrier increases obviously, when polyaniline doped with DBSA is irradiated with light. Mixture of sensitive material is advantageous to the absorption of polyaniline in visible light spectrum, and the conductivity is also improved. The results of dielectric measurements on polyaniline doped with DBSA in an Al-PAn-DBSA-Al configuration as function of frequency and temperature are reported. The space-charge polarization phenomenon is observed. Carrier lifetime is microsecond magnitude and mobility is (0.001～0.1) cm 2/V·s, which are obtained by calculation or experiment. The active energy is obtained from the relation between conductivity and temperature. The conducting mechanism of PAn-DBSA is analyzed.

Sn-fused perylene diimides: Synthesis, mechanism, and properties

The first example of metal Sn-fused perylene diimides(PDI)derivative(Sn-PDI)was designed,synthesized,and investigated.To obtain this type compound,a simple one-pot synthesis,named stannylative cycloaddition reaction,has been successfully developed via a palladium-based catalyst system.The novel mechanism exhibits that the reaction experiences oxidative addition,Pd-cyclization,stannylation,Pd-Sn-cyclization,and reductive elimination processes successively.This stannylative cycloaddition does realize uniqueσ-πhyperconjugation effect and therefore significantly influencing on the photophysical,electrochemical and excited state properties.Compared with those of PDI,both of the absorption and fluorescence spectra of Sn-PDI display large red-shifts over 20 nm.The electron energy levels of Sn-PDI have changed with an uncommon regulation.And Sn-PDI gives a considerably raised highest occupied molecular orbital(HOMO)level of-6.00 eV More importantly,the singlet excitons of Sn-PDI could efficiently intersystem cross(ISC)into triplet state with a long lifetime of 17.8μs,which is far longer than that(4.4 ns)of PDI.

New D-π-A dyes for efficient dye-sensitized solar cells

Functional organic dyes have promising prospect in dye-sensitized solar cells as a crucial element, of which sensitizers based on donor-π-acceptor are the most important dyes. On the basis of the structures of the aromatic amine donors such as triphenylamine and indoline, this paper reviews the photoelectric conversion properties of organic sensitizers since 2008, and highlights research work in our laboratory in this area.

Effect of Conformation on UV-Vis Absorption Spectra of Disazo Reactive Red Dyes

In this study,twenty disazo reactive red dyes with J acid as coupling components were selected,and their ground state geometry were studied with BLYP functional and TZVP basis set. The UV-vis absorption spectra were calculated by time-dependent density functional theory（TDDFT） employing B3 LYP and PBE0 hybrid functionals and TZVP basis set,and the absolute mean errors are 0.094 e V and 0.133 e V for B3 LYP and PBE0,respectively. From the comparison of the calculated λ_（max） of the three conformations of disazo reactive red dye,cis-,trans-,and azo,with that of experimental one,we find out that conformation plays an important role on UV-Vis absorption. Dyes 6 and 8 exist in azo conformation rather than in cis-conformation. ＂Hole-electron＂ distribution analysis reveals that although these λ_（max） arises from different electron transitions,these electron excitations have the same character of local excitation（LE）.