Use of Thienylenevinylene and Ethynyl Molecular Bridges in Organic Dyes for Dye‐Sensitized Solar Cells: Implications for Device Performance

Abstract

The synthesis, full characterization, and use of a series of organic dyes with thienylenevinylene and ethynyl bridges as light-harvesting chromophores in TiO 2 -based photoelectrochemical dye-sensitized solar cells are described. A maximum light-to-energy conversion efficiency of h = 5.47 % under standard conditions is obtained for the organic dye denoted as FL16, which consists of an N,N-bis(4-hexyloxyphenyl)aniline donor moiety, an ethynylthieno[3,2-b]thiophene p bridge, and a 2-cyanoacrylic acid acceptor group. The device properties are investigated by charge extraction and transient photovoltage measurements.

New acceptor–π-porphyrin–π-acceptor systems for solution-processed small molecule organic solar cells

“…35 To a solution of 5a,b 36 (1 eq) in carbon tetrachloride (CCl 4 , 1.25 mL/mmol) was added PhI(OCOCF 3 ) 2 (0.55 eq) and molecular iodine (I 2 , 0.5 eq).…”

Optical and Photovoltaic Properties of Thieno[3,2-b]thiophene-Based Push–Pull Organic Dyes with Different Anchoring Groups for Dye-Sensitized Solar Cells

“…The structures of the push–pull dyes 3a–b and the synthetic protocols followed are depicted schematically in Scheme . The dyes are based on a thieno­[3,2- b ]­thiophene π-spacer, which exhibits good charge-transfer properties, excellent π-conjugation, and low geometric relaxation energy upon oxidation. , Triphenylamine was chosen as the donor group because of its excellent electron-donating ability, hole-transport properties, and capacity to suppress the aggregation of the dye through its nonplanar structure. ,,,− Combined theoretical and experimental studies (optical, redox, and photovoltaic) were carried out to determine the most efficient heterocyclic dye as sensitizer for DSSCs.…”

“…Common electron-donor groups, including diphenylamine, , carbazole, indoline, , and triphenylamine in particular, are extensively used in organic photovoltaics as an excellent electron source, offering extensive possibilities for modifying the structure, function, light harvesting, energy levels, charge generation, and separation. Additionally, they have nonplanar structures that minimize aggregation and display high conversion efficiencies in DSSCs. ,− The conjugation path usually involves thiophene, − ,,, ethene, ethyne, , or benzene units. , Because of their excellent charge-transport properties, the most efficient systems for DSSCs frequently contain thiophene units, − ,,,,, such as oligothiophenes, fused thiophenes, or alkylenedioxythiophenes. The fused ring thienothiophene moiety offers even better π-conjugation and smaller geometric relaxation energy losses upon oxidation than bithiophene. , …”

Charge recombination losses in thiophene-substituted porphyrin dye-sensitized solar cells

“…Firstly, the trimethylsilyl group was quantitatively removed by reaction with TBAF and this was followed by copper-free Pd-catalysed Sonogashira coupling [22] with 2-iodothiophene derivatives 3aeb [23,24] Under these conditions, the reaction proceeded smoothly to afford aldehydes 4a,b in 83% and 80% yield, respectively. Subsequent Knoevenagel condensation of 4a,b with cyanoacetic acid, using piperidine as base, yielded 1a,b in 89% and 82% yields, respectively, after purifi-cation by column chromatography (silica gel, chloroform: methanol 10:1).…”