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

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 ( V RP ) 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 V RP 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.