Molecular Level Factors Affecting the Efficiency of Organic Chromophores for p-Type Dye Sensitized Solar Cells

Abstract

Abstract:A series of mono-and di-branched donor-π-acceptor charge-separated dyes incorporating triphenylamine as a donor and either Dalton's or benzothiadiazole group as strong acceptors was synthesized and its fundamental properties relevant to the sensitization of nanocrystalline NiO investigated. The dyes exhibited an intense visible absorption band with a strong charge transfer character favorable to NiO sensitization, shifting the electron density from the donor to the acceptor branches. Nevertheless, the computed exciton binding energy is circa twice that of a common literature standard (P1), suggesting a more difficult charge separation. When tested in p-type dye-sensitized solar cells the dyes successfully sensitized NiO electrodes, with photocurrent densities about half than that of the reference compound. Being recombination kinetics comparable, the larger photocurrent generated by P1 agrees with the superior charge separation capability originating by its smaller exciton binding energy.

Modular synthesis of simple cycloruthenated complexes with state-of-the-art performance in p-type DSCs

“…Before discussing the results, we draw attention to the fact that literature photoconversion efficiencies (Z) of standard dye P1 in p-type DSCs show significant variation. 33,39,40 Contributing factors include the method of NiO fabrication and layer thickness, 32,33 and the electrolyte (MeCN/I 2 /LiI, MeCN/I 2 / LiI/TBP, or LiI/I 2 /propylene carbonate). [41][42][43][44][45][46] The use of MeCN in place of propylene carbonate in the electrolyte is beneficial in terms of short-circuit current density (J SC ).…”

Metal‐Free Organic Dyes for NiO‐Based Dye‐Sensitized Solar Cells: Recent Developments and Future Perspectives

“…Triphenyl amine-based organic push-pull dyes reported by Zhang, [112] Li, [113] and Karamshuk. [114] between the molecular properties of the dyes and their corresponding photovoltaic performance.…”

Push–pull organic dyes and dye-catalyst assembly featuring a benzothiadiazole unit for photoelectrochemical hydrogen production

“…31 BTD is an electron-decient unit, widely used in the synthesis of dyes for DSSCs, since it increases the push-pull effect in the dye structure, thus shiing the internal charge transfer (ICT) absorption band towards longer wavelengths and improving the spatial separation of HOMO and LUMO orbitals. 32,33 In this work, our goal was to evaluate the potential of the IDT-BTD chromophore for the preparation of dye-catalysts assemblies specically designed for photoelectrochemical hydrogen production. To this purpose, we embedded a benzothiadiazole unit in a D-p-A type chemical structure, and the resulting dye was later covalently assembled with the hydrogenevolving cobalt diimine dioxime catalyst.…”

“…31 BTD is an electron-deficient unit, widely used in the synthesis of dyes for DSSCs, since it increases the push–pull effect in the dye structure, thus shifting the internal charge transfer (ICT) absorption band towards longer wavelengths and improving the spatial separation of HOMO and LUMO orbitals. 32,33…”