Search

Specific solvatochromic D-π-A-type pyridinium dyes were designed and developed as photosensitizers for dye-sensitized solar cells (DSSCs). The dyes have N-sulfobutylpyridinium or N-(carboxybutyl)pyridinium bromide as an electron-withdrawing anchoring group. The two dyes show specific solvatochromism, leading to a large bathochromic shift of the absorption band in halogenated solvents. Moreover, a dye-adsorbed TiO2 film immersed into halogenated solvents exhibits specific solvatochromism, as does a dye solution of halogenated solvents. DSSCs based on specific solvatochromic D-π-A-type pyridinium dyes and halogenated solvents as electrolyte solvent were prepared and their photovoltaic performance investigated. It was found that the appropriate combination of solvatochromic dyes with electrolyte solution and the effective interaction between solvatochromic dyes and TiO2 surface can lead to not only an enhancement of light-harvesting efficiency (LHE), but also efficient electron injection from the dye to the conduction band (CB) of TiO2. This work demonstrates that the solvatochromism of organic dyes is a key consideration for high-performance DSSCs based on organic dye sensitizers. [ABSTRACT FROM AUTHOR]

D–π–A type boron dipyrromethene (BODIPY) dye YH-1, which has two pyridyl groups as electron-withdrawing-anchoring groups at the end of the 3- and 5-positions and a carbazole-diphenylamine moiety as an electron donor at the 8-position on the BODIPY core, was designed and developed as a photosensitizer for dye-sensitized solar cells (DSSCs). It was found that the dye YH-1 possesses a good light-harvesting efficiency (LHE) in the red/near-IR (NIR) region and good adsorption ability on TiO2 film. We demonstrate that the expansion of the π-conjugated system by the introduction of not only the carbazole-diphenylamine moiety and the thiophene unit at the 8-position but also two thienylpyridines at the 3- and 5-positions on the BODIPY core can lead to red-shift and broadening of the absorption band in the red/NIR region. DSSCs based on YH-1 exhibit incident photon-to-current conversion efficiency of ca. 10% over a range of 500 to 700 nm, with an onset at 800 nm. [ABSTRACT FROM AUTHOR]

As a new class of D–π–A dye sensitizer for dye-sensitized solar cells (DSSCs), we have designed and synthesized the functionally separated D–π–A fluorescent dye YJY-1 with an aldehyde as an electron-accepting group and a carboxyl group as an anchoring group. Furthermore, not only to evaluate the usefulness of D–π–A dye sensitizers functionally separated into an electron acceptor moiety and an anchoring group, but also to gain insight into the influences of interaction between the aldehyde of the dyes and the TiO2 surface on the photovoltaic performances of DSSCs, the D–π–A fluorescent dye YJY-2 with an aldehyde as an electron-accepting group, but without a carboxyl group, was also synthesized. It was found that the functionally separated D–π–A dye YJY-1 exhibits not only high adsorption ability onto TiO2 film through the carboxyl group, but also efficient electron injection from the dye into the CB of TiO2 through the aldehyde which is located close to the TiO2 surface. This work demonstrates that the functionally separated D–π–A dyes would be expected to be one of the most promising classes of organic dye sensitizers for DSSCs. [ABSTRACT FROM AUTHOR]

When TiO2 electrodes were dipped in chloroform solutions containing disilanylene--oligothienylene polymers and the solutions were irradiated (λmax>400 nm), the polymer-bound electrodes were obtained, which could be used for dye-sensitized solar cells. [ABSTRACT FROM AUTHOR]

Novel dye-sensitized TiO2 solar cells have been developed using a variety of oligothiophenecarboxylic acids. These cells showed relatively high photovoltaic performances (η = 0.41-1.29%), which are largely dependent on the chain lengths of the oligothiophenes and the number of the carboxylic groups. [ABSTRACT FROM AUTHOR]

Abstract: New dithienogermole-based conjugated polymers were synthesized by the Stille coupling reactions of distannyldithienogermole and dibromoarene, and their photovoltaic properties were studied. These polymers possess low band gaps with broad absorptions covering the 400–800 nm range, and exhibit good film forming properties. Bulk hetero-junction solar cells prepared from blends of these polymers with PC70BM exhibit high power conversion efficiency up to 2.38%. [Copyright &y& Elsevier]

Novel donor–π–acceptor (D–π–A) dyes composed of oligothiophenes having 3,4-ethylenedioxythiophene (EDOT) as a π-linker have been synthesized. The introduction of EDOT unit in oligothiophenes and the elongation of π-conjugation length of oligothiophenes led to a red-shift of absorption bands of the D–π–A dyes. It was found that a D–π–A dye having EDOT-containing quaterthiophene exhibited the excellent light-harvesting ability up to 800 nm. [ABSTRACT FROM AUTHOR]

Abstract: New-type donor–acceptor π-conjugated benzofuro[2,3-c]oxazolo[4,5-a]carbazole fluorescent dyes with various lengths of non-conjugated alkyl chains containing a carboxyl group at the end position have been developed and their photovoltaic performances of dye-sensitized solar cells are investigated. It is found that in spite of the lengths of the alkyl chains, due to flexibility of alkyl chain, the cyano group of the dyes is located in close proximity to TiO2 surface and thus a good electron communication between the dyes and TiO2 surface is established. [Copyright &y& Elsevier]