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Three new metal-free organic dyes with the [1]benzothieno[3,2-b]benzothiophene (BTBT) p-bridge, having the structure donor-p-acceptor (D-π-A) and labeled as 19, 20 and 21, have been designed and synthesized for application in dye-sensitized solar cells (DSSC). Once the design of the π-acceptor block was fixed, containing the BTBT as the π-bridge and the cyanoacrylic group as the electron acceptor and anchoring unit, we selected three donor units with different electron-donor capacity, in order to assemble new chromophores with high molar extinction coefficients (ε), whose absorption features well reflect the good performance of the final DSSC devices. Starting with the 19 dye, which shows a molar extinction coefficient ε of over 14,000 M-1 cm-1 and takes into account the absorption maximun at the longer wavelength, the substitution of the BFT donor unit with the BFA yields a great enhancement of absorptivity (molar extinction coefficient ε > 42,000 M-1 cm-1), until reaching the higher value (ε > 69,000 M-1 cm-1) with the BFPhz donor unit. The good general photovoltaic performances obtained with the three dyes highlight the suitable properties of electron-transport of the BTBT as the π-bridge in organic chromophore for DSSC, making this very cheap and easy to synthesize molecule particularly attractive for efficient and low-cost photovoltaic devices. [ABSTRACT FROM AUTHOR]

An organic dye containing two D-π-A branches linkedwitha thiophene unit has been designed and synthesized for efficient dye-sensitizedsolar cells (DSSCs). As compared to the rod-shape of the single D-π-Aanalogue dye, the cross shape of the double D-π-A branched dyeis favorable for reducing intermolecular interaction and retardingcharge recombination. Controlled intensity modulated photovoltagespectroscopy reveals that electron lifetime for the double D-π-Adye-based DSSC is 14-fold longer than that for the corresponding singleD-π-A dye-based DSSC. Linking two D-π-A branches witha thiophene unit increases open-circuit photovoltage by 100 mV andshort-circuit photocurrent by 4.10 mA cm–2. As aconsequence, power conversion efficiency is enhanced by about 2-fold.This work presents a new route to designing sensitizers with highsuppression ability of charge recombination toward high-performanceDSSCs. [ABSTRACT FROM AUTHOR]

A series of metal-free organic dyes exploiting different combinations of (hetero)cyclic linkers (benzene, thiophene, and thiazole) and bridges (4H-cyclopenta[2,1-b:3,4-b′]dithiophene (CPDT) and benzodithiophene (BDT)) as the central π-spacers were synthesized and characterized. Among them, the sensitizer containing the thiophene and CPDT showed the most broad incident photon-to-current conversion efficiency spectra, resulting in a solar energy conversion efficiency (η) of 6.6%. [ABSTRACT FROM AUTHOR]

In our search for thiophene fluorophores that can overcome the limits of currently available organic dyes in live-cell staining, we synthesized biocompatible dithienothiophene-S,S-dioxide derivatives (DTTOs) that were spontaneously taken up by live mouse embryonic fibroblasts and HeLa cells. Upon treatment with DTTOs, the cells secreted nanostructured fluorescent fibrils, while cell viability remained unaltered. Comparison with the behavior of other cell-permeant, newly synthesized thiophene fluorophores showed that the formation of fluorescent fibrils was peculiar to DTTO dyes. Laser scanning confocal microscopy of the fluorescent fibrils showed that most of them were characterized by helical supramolecular organization. Electrophoretic analysis and theoretical calculations suggested that the DTTOs were selectively recognized by the HyPro component of procollagen polypeptide chains and incorporated through the formation of multiple H-bondings. [ABSTRACT FROM AUTHOR]

A new class of organic sensitizers incorporating a benzo[1,2-b:4,5-b′]dithiophene (BDT) unit as conjugated spacer has been synthesized and successfully used for dye-sensitized solar cells (DSSCs). The length of the π-conjugated spacers has a strong impact on electro-optical properties of these dyes, leading to the conversion efficiencies ranging from 4.17 to 5.68% under AM 1.5 G irradiation. This result indicates that the BDT unit is a promising candidate in organic sensitizers. [ABSTRACT FROM AUTHOR]

New dipolar compounds incorporating a dithieno[3,2-b:2′,3′-d]thiophene unit as the electron donor, an oligothiophene moiety as the conjugated spacer, and 2-cyanoacrylic acid as the electron acceptor have been synthesized. These nonarylamine type metal-free organic compounds have been successfully used as the sensitizers of dye-sensitized solar cells (DSSCs). The conversion efficiencies of the DSSCs range from 3.54 to 5.15% under AM 1.5 G irradiation. The best efficiency reached ∼70% of the ruthenium dye N719-based standard cell fabricated and measured under similar conditions. [ABSTRACT FROM AUTHOR]

New organic dyes composed of the benzo[b]furan donor, thiophene-conjugated bridge, and cyano acrylic acid acceptor have been newly synthesized through the one-pot coupling cyclization key step. Nanocrystalline TiO2 dye-sensitized solar cell was fabricated using this dye. A solar-to-electric conversion efficiency of 6.65% and 4.70% is achieved with 1 and 2, respectively. [ABSTRACT FROM AUTHOR]

The article describes the design and synthesis of a molar extinction organic sensitizer coded C203 with a fused dithienothiophene unit for efficient and stable dye-sensitized solar cells. According to the authors, a ~7% cell with an organic dye showing an excellent stability measured under the thermal and light-soaking dual stress was demonstrated in combination with a solvent-free ionic liquid electrolyte.