Asymmetric double donor-π-acceptor dyes based on phenothiazine and carbazole donors for dye-sensitized solar cells

The Performance Evaluation of Meso-Tetraphenyl Porphyrin and Azo Dyes as Photosensitizers in Dye-sensitized Solar Cells

The photovoltaic properties of five different mono-azo function and meso-tetraphenyl porphyrin dyes have been investigated by computational DFT/TDDFT calculations and measurement of the J-V properties of their cells. The photovoltaic efficiency of the cells based on these dyes were determined by both experimental and theoretical methods. The efficiency-to-cost ratios of the azo-dye cells showed that they could be cheaper substitutes to porphyrin-based cells. Eriochrome blue black (EBB) and eriochrome black T (EBT) cells were shown to possess the best photovoltaic properties by the two methods employed (theory and experiment). The presence of two naphthol moieties at both ends of their -N = N- group has been adduced as possible reason for their relatively outstanding performance. The extremely low efficiency-to-cost ratio obtained for cell-POR suggests that the use of porphyrin as sensitizer may not be as economically viable as some azo dyes. MTO, EBB and EBT were found to be the most cost-effective among the investigated dyes. The porphyrin's low performance may have been amplified by the absence of an effective anchor group in its molecular structure.

Synthesis of efficient bi-anchoring bifuran/biphenyl derivatives for dye-sensitized solar cell applications†

The synthesis, description, and demonstration of dye-sensitive solar cell sensitizers containing bifuran/biphenyl derivatives with cyanoacetic acid, barbiturate, thiobarbituric acid, and 4-carboxylcyanoacetamides have been reported. A photovoltaic performance measurement was conducted using the Ru(ii) dye N3 as a reference to examine the effects of different electron acceptor units and replacement of the π-spacer bifuran by biphenyl units on the photophysical, electrochemical, and photovoltaic properties of eight new distinct organic dyes HB-1–8. The new organic dyes HB-1–8 were prepared and compared with the N3 metal dye. Density functional theory calculations were carried out to explore the ground state geometrical structures and electronic structures of the eight dyes. Under standard global AM 1.5 solar condition, the solar cells based on HB-1–8 show the overall power conversion efficiencies of 2.93–5.51%. The presented research shows that the organic dye photovoltaic performances can vary greatly depending on the type of electron donor and acceptor used. Dye HB-3 exhibited the highest efficiency among the eight investigated dyes, reaching 5.51% with a V_OC value higher than N3.

We have synthesized new metal-free dyes (HB-1–8) containing bifuran/biphenyl derivatives for dye-sensitized solar cells. Dye HB-3 exhibited the highest efficiency among the eight investigated dyes, reaching 5.51% with a V_OC value higher than N3.

Investigations of New Phenothiazine-Based Compounds for Dye-Sensitized Solar Cells with Theoretical Insight

New D-π-D-π-A low-molecular-weight compounds, based on a phenothiazine scaffold linked via an acetylene unit with various donor moiety and cyanoacrylic acid anchoring groups, respectively, were successfully synthesized. The prepared phenothiazine dyes were entirely characterized using nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. The compounds were designed to study the relationship between end-capping donor groups’ structure on their optoelectronic and thermal properties as well as the dye-sensitized solar cells’ performance. The effect of π-conjugation enlargement by incorporation of different heterocyclic substituents possessing various electron–donor affinities was systematically experimentally and theoretically examined. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were implemented to determine the electronic properties of the novel molecules.

Theoretical study of D-A'-π-A/D-π-A'-π-A triphenylamine and quinoline derivatives as sensitizers for dye-sensitized solar cells

We have designed four dyes based on D-A'-π-A/D-π-A'-π-A triphenylamine and quinoline derivatives for dye-sensitized solar cells (DSSCs) and studied their optoelectronic properties as well as the effects of the introduction of alkoxy groups and thiophene group on these properties. The geometries, single point energy, charge population, electrostatic potential (ESP) distribution, dipole moments, frontier molecular orbitals (FMOs) and HOMO-LUMO energy gaps of the dyes were discussed to study the electronic properties of dyes based on density functional theory (DFT). And the absorption spectra, light harvesting efficiency (LHE), hole-electron distribution, charge transfer amount from HOMO to LUMO (Q CT), D index, H CT index, S m index and exciton binding energy (E coul) were discussed to investigate the optical and charge-transfer properties of dyes by time-dependent density functional theory (TD-DFT). The calculated results show that all the dyes follow the energy level matching principle and have broadened absorption bands at visible region. Besides, the introduction of alkoxy groups into triarylamine donors and thiophene groups into conjugated bridges can obviously improve the stability and optoelectronic properties of dyes. It is shown that the dye D4, which has had alkoxy groups as well as thiophene groups introduced and possesses a D-π-A'-π-A configuration, has the optimal optoelectronic properties and can be used as an ideal dye sensitizer.

Optical and Electronic Properties of Molecular Systems Derived from Rhodanine

Push-pull functional compounds consisting of dicyanorhodanine derivatives have attracted a lot of interest because their optical, electronic, and charge transport properties make them useful as building blocks for organic photovoltaic implementations. The analysis of the frontier molecular orbitals shows that the vertical transitions of electronic absorption are characterized as intramolecular charge transfer; furthermore, we show that the analyzed compounds exhibit bathochromic displacements when comparing the presence (or absence) of solvent as an interacting medium. In comparison with materials defined by their energy of reorganization of electrons (holes) as electron (hole) transporters, we find a transport hierarchy whereby the molecule ( Z)-2-(1,1-dicyanomethylene)-5-[(4-dimethylamino)benzylidene]-1,3-thiazol-4 is better at transporting holes than molecule ( Z)-2-(1,1-dicyanomethylene)-5-(tetrathiafulvalene-2-ylidene)-1,3-thiazol-4.

Interaction of pyridine π-bridge-based poly(methacrylate) dyes for the fabrication of dye-sensitized solar cells with the influence of different strength phenothiazine, fluorene and anthracene sensitizers as donor units with new anchoring mode

A simple and low-cost approach for the synthesis of three novel propeller-shaped (D₂)–π–A type organic polymer dyes has been developed; a new acceptor and π-bridge (PYN) were used to tune the photoelectric properties: DFT studies.