ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

An optoelectronic study to design better benzodithiophene (BDT) donor unit based non-fullerene organic solar cells (OSCs): the DFT approaches

Faheem Abbas, Usman Ali, Aqsa Tallat, Hafiz Muhammad Rizwan Ahmad, Sabir Ali Siddique, Zonish Zeb, and Muhammad Bilal Ahmed Siddique

Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, People’s Republic of China

E-mail: usmanqureshi@iccas.ac.cn

Received: 12 October 2021  Accepted: 5 April 2022

Abstract:

Herein present research work, we have designed benzodithiophene based four new molecules (D1–D4) linked with different non fullerene end-capped acceptor units. The structural modifications of four designed organic solar cell molecules have been theoretically analyzed and results are compared with reference molecule R. DFT and TD-DFT approaches have been employed for assessment of photophysical characteristics, natural transition orbitals, density of state, open- circuit voltages (\(V_{{{\text{OC}}}}\)), transition density matrix and charge transfer analysis. The maximum absorption wavelength (\(\lambda_{\max }\)) of designed molecule D4 is large (618.42 nm) with small excitation energy (\(\Delta E\) = 2 eV) and exciton binding energy (E_b = 0.25 eV). The open circuit voltages (\(V_{{{\text{OC}}}}\) = 1.59 eV) of D4 are also higher than others designed molecules including R molecule which exhibits their strong photovoltaic properties for further construction of bulk heterojunction organic solar cell molecules.

Keywords: Benzodithiophene (BDT); Binding energy; Structural modifications; Transition density matrix (TDM); Photophysical properties

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02224-x

Chemical Papers 76 (8) 4977–4987 (2022)