Push-pull effect on the charge transport properties in anthra[2,3-b]thiophene derivatives used as dye-sensitized and hetero-junction solar cell materials

• DFT and TDDFT have been applied to investigate the properties of interests.
• Intra-molecular charge transfer was observed from donor to acceptor moieties.
• The designed materials would be good contenders for photovoltaic technology.

Density functional theory (DFT) and time dependent DFT have been applied to shed light on the electronic and charge transport properties in anthra[2,3-b]thiophene derivatives (DATP-a, DATP-b, DATP-c, DATP-d, DATP-e, and DATP-f). The neutral, cation and anion ground state geometries were optimized at DFT-B3LYP/6-31G** level of theory. The TDDFT has been used for the excitation energy calculations. The electron injection (ΔGinject), electron coupling constants (|VRP|VRP) and light harvesting efficiencies (LHE) of studied compounds have been discussed. The quantum chemical calculations have been performed to gain insight into electronic and charge transport properties. The ΔGinject and |VRP|VRP of new designed derivatives showed that these sensitizers would be efficient dye-sensitized solar cell materials. The derivatives containing COOH (DATP-a, DATP-c, and DATP-e) have superior LHE as compared to those systems which have NO2. The DATP-b, DATP-d, and DATP-f have the high electron affinity which would improve the electron transport toward cathode in hetero-junction solar cells. The largest diagonal band gap has been observed for DATP-b, DATP-d, and DATP-f revealing these would have higher short-circuit current density (Jsc) and fill factor (FF). The hole reorganization energies of DATP-a and DATP-b are smaller than pentacene revealing that these materials would be efficient charge transporters.

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