Search

The performance of a new indoline dye having a carboxylated 1,3-idandione unit linked with a hexythienyl ring showed higher conversion efficiency than the analogous dye without the hexyl group. [ABSTRACT FROM AUTHOR]

Novel benz[ c,d ]indolenine-based unsymmetrical near-infrared squaraine dyes having germinal butyl ( η = 0.55%) and octyl ( η = 0.58%) groups at another indolenine ring exhibited higher conversion efficiency than the usually used methyl derivative ( η = 0.38%). The germinal butyl and octyl groups can inhibit aggregation formation and approaching I 3 − species to improve the conversion efficiency. [ABSTRACT FROM AUTHOR]

Novel xanthene dyes having thienyl and thieno[3,2- b ]thienyl rings as auxochrome have been synthesized. The UV–vis absorption maximum in dichloromethane was in the order of the auxochrome: NEt 2 (Rhodamine B, 558 nm) < 2-thienyl (569 nm) < 5-thieno[3,2- b ]thienyl (608 nm). These new xanthene dyes colored only in non-hydrogen-bond accepting solvents such as chloroform and dichloromethane. The lactone precursors of the thienyl and thieno[3,2- b ]thienyl derivatives colored by adding strong acids whose p K a value is lower than −2.2 and 0.23, respectively, whereas that of rhodamine B colored by adding weak acids whose p K a value is lower than 4.7. These results originate from less stability of colored cationic dyes by the heteroaromatics than by the diethylamino auxochrome. [ABSTRACT FROM AUTHOR]

Abstract: 1-Alkyl-2-[4-(diethylamino)styryl]pyridinium salts showed fluorescence maxima at around 650 nm in the solid state depending on the alkyl group and counter anion. 1-Butyl-2-[4-(diethylamino)styryl]pyridinium bis(perfluorobutylsulfonyl)imide exhibited the fluorescence maximum at 652 nm with the highest quantum yield 0.16 in the crystalline form. The single X-ray crystallography suggests that this compound exhibits isolated dimer-type packing leading to fluorescence in the solid state. [Copyright &y& Elsevier]

Abstract: DN350 exhibited better performance than D149 in zinc oxide dye-sensitized solar cell in the presence of cholic acid (CA). The performance of DN350 was improved in the order of cholic acids: ursodeoxycholic acid (UDCA) > chenodeoxycholic acid (CDCA) > CA. This result could come from the bathochromic shift of the UV–vis absorption band of DN350 on zinc oxide to improve short-circuit photocurrent density. [Copyright &y& Elsevier]

Abstract: A new indoline dye in which a double rhodanine acceptor is attached to the indoline moiety by a p-phenylene spacer on the indoline–nitrogen, has been examined for its performance as a sensitizer for zinc oxide dye-sensitized solar cells. In the presence of cholic acid, chenodeoxycholic acid, or lithocholic acid; the performance was greatest for lithocholic acid as this showed the greatest reduction in dye H-aggregate formation. [Copyright &y& Elsevier]

Abstract: The cell performance of novel benzoindoline dyes on zinc oxide prepared by template cathode electro-deposition method was compared with that of known indoline dyes. Among cyanoacrylic, single and double rhodanine acetic acid derivatives, the cyanoacrylic benzoindoline dye showed better performance than the indoline dye (D131) due to larger J sc value which comes from its positive E ox level and bathochromic UV–vis absorption band. [Copyright &y& Elsevier]

Abstract: The solar-light-to-electricity conversion efficiency of substituted indoline dyes depended on short-circuit photocurrent density which is affected by maximum incident photon-to-current efficiency. The oxidation potential of the double rhodanine indoline dyes needed to be >∼0.2 V vs Fc/Fc+ in acetonitrile to show high incident photon-to-current efficiency in a zinc oxide, dye-sensitized solar cell. To make a molecular design of highly efficient indoline dyes, the HOMO energy level should be more negative than ∼−4.9 eV by the DFT calculations. [Copyright &y& Elsevier]

The effects of the position and the type of carboxyl anchor group in double rhodanine-type indoline dyes on the performance of a zinc oxide dye-sensitized solar cell were examined. The optimum position for the carboxymethyl group was on the inner rhodanine moiety; a carboxymethyl group gave optimum results among carboxymethyl, -ethyl, and -propyl derivatives. [Copyright &y& Elsevier]

Abstract: The UV–vis absorption and fluorescence spectra, solubility, and application as emitters in single-layer EL devices of novel perylene-3,4:9,10-tetracarboxidiimide-centred dendrimers (G n -Perys) were examined. G n -Perys showed absorption maxima (λ max) at 459, 491, and 529nm in chloroform. The emission maxima (λ em) were observed at 537, 576, and 621nm. The fluorescence intensities of G1 -, G2 -, and G3 -Perys were ca. one-twentieth compared with that of G0 -Pery. However, the concentration-quenching of G n -Perys (n =1, 2, 3) was improved. The solubility of G n -Perys increased at higher generation. The electroluminescence (EL) maxima of G n -Perys in single-layer EL devices containing PVK and PBD as host materials were observed at around 430 and 600nm, there being white emission. No remarkable difference in the EL characteristics was observed among G n -Perys. [Copyright &y& Elsevier]

Abstract: A series of semisquaric acids were examined as sensitizers for the zinc oxide solar cell prepared by a one-step cathode deposition template method. Their cell performance was rather low due to high oxidation potential (E ox) of semisquaric acids. However, the performance was improved by introducing long alkyl group on the nitrogen atom at the heteroaromatic moiety. A N-octadecylindolium derivative showed the best performance: the incident photon-to-current efficiency (IPCE) 38.0% at absorption maximum (λ max) 423nm, short circuit photocurrent density (I sc) 1.116mAcm−2, open circuit photovoltage (V oc) 0.421V, fill factor (ff) 0.57, and solar-light-to-electricity conversion efficiency (η) 0.27%, respectively. [Copyright &y& Elsevier]

Abstract: 1,2,3,4-Tetrafluoro-9,10-anthraquinones reacted with a molar amount of bifunctional nucleophiles, such as 2-aminophenol, catechol, 2-aminobenzenethiol, ethylenediamine, and 1,4-butanediamine to produce the 1,2-cyclized products, which further reacted with another molar amount of bifunctional nucleophiles to afford the dicyclized derivatives. [Copyright &y& Elsevier]

A series of 3-aryl-4-hydroxycyclobut-3-ene-1,2-diones were synthesized and examined as sensitizers for a TiO2 solar cell. The compounds showed strong affinity for TiO2 and the fluorescence intensity and self-assembly of the 3-aryl-4-hydroxycyclobut-3-ene-1,2-diones on the TiO2 surface were important factors in enhancing the solar-light-to-electricity conversion efficiency. The highest efficiency of 0.96% was observed for 3-[4-(didodecylamino)phenyl]-4-hydroxycyclobut-3-ene-1,2-dione. [Copyright &y& Elsevier]

Abstract: 6-Substituted 2,3-dicyano-5-[4-(diethylamino)styryl]-7-methyl-6H-1,4-diazepines were applied as red dopants in single-layer organic electroluminescence (EL) devices. EL maxima were observed at around 610nm and the EL intensity of the 6-alkyl derivatives was higher than that of the unsubstituted variant under fixed bias voltage due to increased current density and improved η ext in the devices. [Copyright &y& Elsevier]

A range of novel phthalocyanine structures containing polyfluoroalkyloxy groups at the axial sites have been successfully synthesised. They were tested for solubility in a number of solvents. The polyfluoroalkyloxy groups were found to impart higher solubility than the corresponding polyfluoroalkanoyloxy and alkoxy derivatives. The highest solubility was found in ether. [Copyright &y& Elsevier]

Unsymmetrical and symmetrical bis(hetaryl)azo dyes were prepared by diazotisation-coupling and oxidation reactions in low to good yields. Their absorption maxima were observed in the range of 427–631 nm, being more bathochromic than the corresponding non-hetarylazo derivatives. No remarkable difference of decomposition temperature in the bis(hetaryl)azo dyes was observed except for the pyridone derivative. The photofading of benzothiazolylazo derivatives in ethanol in air occurred by way of reductive processes. [Copyright &y& Elsevier]

Any liquid azo dyes, in which auxochrome such as dialkylamino, alkoxy, and amino group is attached in a molecule, were produced. In a series of 2-alkyl-4’-(dimethylamino)azobenzenes, the butyl, hexyl, octyl, and dodecyl derivatives were liquid at room temperature, whereas the propyl, 1-methylethyl, 1-methylpropyl, 1,1-dimethylethyl, and octadecyl derivatives were solid. Thus, it is essential for liquid azo dyes to have a medium n -alkyl group at the 2-position. In a series of 2-butyl-4’-(dialkylamino)azobenzenes, the dimethylamino, diethylamino, dibutylamino, dioctylamino, and didodecylamino derivatives were liquid. 2-Butyl-4’-methoxyazobenzene and 4-amino-3,5-dimethyl-2’-butylazobenenzne were also liquid, whereas 2-butyl-4’-hydroxyazobenznene, 4-amino-2’-butylazobenzene, and 2-butyl-4’-(methylamino)azobenzene were solid. The prevention of π/π stacking, alkyl–alkyl interactions, and intermolecular hydrogen bond could produce liquid azo dyes. [ABSTRACT FROM AUTHOR]

The solid-state fluorescence intensity of coumarin dyes depends on the substituents present at the 4- and 7-positions. 7-(Diethylamino)coumarins showed higher solid-state fluorescence quantum yield (Φ f(ss)=0.29–0.40) than 7-aminocoumarins (0.01). In the case of julolydyl coumarins, a 4-methyltetramethyljulolydyl derivative also displayed high Φ f(ss) (0.34), this being greater than that observed for both 4-(perfluoroalkyl)tetramethyljulolydyl (0.09 and 0.10) and 4-methyljulolydyl derivatives (0.01). X-ray crystallographic analysis suggested that coumarin dyes bearing network hydrogen bonds and/or π–π stacking show weak solid-state fluorescence whereas coumarin dyes having isolated monomer- and dimer-type stacking show intense fluorescence. 4-(Perfluoroalkyl)tetramethyljulolydyl derivatives displayed medium fluorescence intensity owing to isolated monomer-type packing with little intermolecular interactions operating between adjacent molecules. [Copyright &y& Elsevier]

Application of a series of styryl dyes for flexible zinc oxide solar cells prepared by the one-step cathode deposition template method was examined. 3-(2-Carboxyethyl)-2-[4-(dimethylamino)styryl]benzothiazolium iodide (27) showed the best performance as the sensitizer. The incident photon-to-current efficiency (IPCE) at around 490nm, maximum short-circuit photocurrent density (J sc), open-circuit photovoltage (V oc), fill factor (ff), and solar-light-to-electricity conversion efficiency (η) were observed to be 54.5%, 6.22mAcm−2, 0.53V, 0.59, and 1.94%, respectively. [Copyright &y& Elsevier]

Abstract: A series of 9-substituted 3,4-perylenedicarboxylic anhydrides were examined as sensitizers for the zinc oxide solar cell prepared by a one-step cathode deposition template method. The best performance was obtained for the bromo derivative. The incident photon-to-current efficiency (IPCE) at 431nm, maximum short-circuit photocurrent density (I sc), open-circuit photovoltage (V oc), fill factor (ff), and solar-light-to-electricity conversion efficiency (η) were observed to be 35.5%, 1.78mAcm−2, 0.46V, 0.64, and 0.52%, respectively. [Copyright &y& Elsevier]

Novel unsymmetrical squarylium dyes containing the strongly electron-donating 4′-amino-2,2′-bis(diethylamino)-4,5′-bithiazole moiety were fluorescent and showed emission maxima around 640 nm. They have both alternant and intramolecular charge-transfer chromophoric systems. [Copyright &y& Elsevier]

New bis(styryl)dicyanodiazepine fluorescent dyes and related derivatives were synthesized by the condensation of 2,3-dicyano-5,7-dimethyl-6H-1,4-diazepine and related compounds with arylaldehydes. Their optimized molecular structures were evaluated by the MOPAC PM3 method and MO calculations were conducted by means of the ZINDO method. The bis(styryl) dye showed very broad visible absorption spectra with triple absorption maxima which can be considered to arise from splitting of the degenerate HOMO''s. The effects of ring size and substituents on the absorption and fluorescence spectra of a series of new styryldiazepine dyes have been interpreted in terms of the non-planar diazepine component of the chromophoric system. The strong intramolecular charge transfer chromophoric system of these dyes exhibited an exceptionally large Stokes shift of more than 100 nm, which resulted in pure red fluorescence at wavelengths beyond 600 nm. [Copyright &y& Elsevier]