Impact of end-group modifications and planarity on BDP-based non-fullerene acceptors for high-performance organic solar cells by using DFT approach

• Published in: Journal of molecular modeling Vol. 28; no. 12; p. 397
• Main Authors: Saeed, Muhammad Umar, Hadia, N. M. A., Iqbal, Javed, Hessien, M. M., Shawky, Ahmed M., Ans, Muhammad, Alatawi, Naifa S., Khera, Rasheed Ahmad
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2022; Springer Nature B.V
• Subjects: Carrier mobility; Characterization and Evaluation of Materials; Charge distribution; Charge transfer; Chemistry; Chemistry and Materials Science; Computer Appl. in Life Sciences; Computer Applications in Chemistry; Conjugation; Current carriers; Density functional theory; Density of states; Electromagnetic absorption; Energy conversion efficiency; Fullerenes; Molecular Medicine; Molecular orbitals; Open circuit voltage; Optical properties; Optoelectronics; Original Paper; Parameters; Photovoltaic cells; Pyrroles - chemistry; Solar cells; Static Electricity; Theoretical and Computational Chemistry; BDP-based small molecules; Molecular planarity parameter; Computational study; Reorganization energies
• ISSN: 1610-2940; 0948-5023
• DOI: 10.1007/s00894-022-05382-7

With the aim to enhance the photovoltaic properties of organic solar cells (OSCs), seven new non-fullerene acceptors ( K1 – K7 ) have been designed by end-group modifications of benzo[2,1-b:3,4-b’]bis(4H-dithieno[3,2-b:2’,3’-d]pyrrole) (BDP)–based small molecule “MH” (which is taken as our reference R ) using computational techniques. To investigate their various optoelectronic parameters, DFT studies were applied using the B3LYP functional at 6-31G (d, p) basis set. The measurement of molecular planarity parameter (MPP) and span of deviation from plane (SDP) confirmed the planar geometries of these structures resulting in enhanced conjugation. Frontier molecular orbital (FMO) and density of states (DOS) analyses confirmed shorter band gaps of K1 – K7 as compared to R , which promotes charge transfer in them. Optical properties demonstrated that these compounds have absorption range from 692 to 711 nm, quite better than the 684 nm of reference R . Molecular electrostatic potential (MEP) and Mulliken’ charge distribution analysis also revealed the presence of epic charge separation in these structures. K1 – K7 showed enhanced LHE values as compared to R putting emphasis on their better abilities to produce charge carrier by absorption of light. Reorganization energies showed that all newly designed compound could have better rate of charge carrier mobility (except K4 ) than R . Calculations of open-circuit voltage ( V oc ) and fill factor (FF) revealed its highest values for K3 and K4 . Among newly designed molecules, K3 showed betterment in all its investigated parameters, making it a strong candidate to get enhanced power conversion efficiencies of OSCs.