Design of new bithieno thiophene (BTTI) central core-based small molecules as efficient hole transport materials for perovskite solar cells and donor materials for organic solar cells

Abstract

This present study focuses on designing five bithienothiophene (BTTI) central core-based small molecules (MPA-BTTI-A1-MPA-BTTI-A5) in exploring the optoelectronic properties to ensure their potentiality as donor candidates for organic solar cells (OSCs) and HTMs. MPA-BTTI-A1 and MPA-BTTI-A3 are tailored by the replacing thiophene-bridge end-capped acceptors on one side terminal of reference (MPA-BTTI-R). Similarly, MPA-BTTI-A2, MPA-BTTI-A4 and MPA-BTTI-A5 have been designed by employing the same strategy on both side terminals. To ascertain stable geometric structures, CAM-B3LYP/6-311G (d,p) is selected and used in all computational simulations. The MPA-BTTI-A1 exhibits the least energy gap of 1.69 eV with greatest λmax at 722 nm in dichloromethane (DCM) and highest dipole moment of 19.59 D in DCM solvent, indicating excellent miscibility as compared to the model/reference. All newly fabricated molecules (MPA-BTTI-A1- MPA-BTTI-A5) suggest excellent operational efficiency due to their higher Voc also relatively high-power conversion efficiency (PCE) in comparison to reference. Also, all fabricated molecules are attributed with a greater estimated PCE of range (20.74–40.3%), than reference (PCE = 16%). The highest electron mobility of 0.0871 eV is observed in MPA-BTTI-A3 andMPA-BTTI-A2 exhibits the highest hole mobility of 0.1334 eV. Hence, the modification scheme is a promising way in designing proficient photovoltaic materials, paving ways for new design and advancement of a small-molecule HTMs for donor contributors for organic solar cells (OSCs) and in PSCs.