Molecular engineering of indenoindene-3-ethylrodanine acceptors with A2-A1-D-A1-A2 architecture for promising fullerene-free organic solar cells

Muhammad Khalid; Momina; Muhammad Imran; Muhammad Fayyaz Ur Rehman; Ataualpa Albert Carmo Braga; Muhammad Safwan Akram

doi:10.1038/s41598-021-99308-7

Molecular engineering of indenoindene-3-ethylrodanine acceptors with A2-A1-D-A1-A2 architecture for promising fullerene-free organic solar cells

Sci Rep. 2021 Oct 13;11(1):20320. doi: 10.1038/s41598-021-99308-7.

Authors

Muhammad Khalid¹, Momina¹, Muhammad Imran², Muhammad Fayyaz Ur Rehman³, Ataualpa Albert Carmo Braga⁴, Muhammad Safwan Akram^{5

6}

Affiliations

¹ Department of Chemistry, Khawaja Fareed University of Engineering and Information Technology, Rahim Yar Khan, 64200, Pakistan.
² Department of Chemistry, Faculty of Science, King Khalid University, P.O. Box 9004, Abha, 61413, Saudi Arabia.
³ Institute of Chemistry, University of Sargodha, Sargodha, 40100, Pakistan.
⁴ Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Prof. LineuPrestes 748, São Paulo, 05508-000, Brazil.
⁵ School of Health and Life Sciences, Teesside University, Middlesbrough, TS1 3BX, UK. Safwan.akram@tees.ac.uk.
⁶ National Horizons Centre, Teesside University, Darlington, DL1 1HG, UK. Safwan.akram@tees.ac.uk.

Abstract

Considering the increased demand and potential of photovoltaic devices in clean, renewable electrical and hi-tech applications, non-fullerene acceptor (NFA) chromophores have gained significant attention. Herein, six novel NFA molecules IBRD1-IBRD6 have been designed by structural modification of the terminal moieties from experimentally synthesized A2-A1-D-A1-A2 architecture IBR for better integration in organic solar cells (OSCs). To exploit the electronic, photophysical and photovoltaic behavior, density functional theory/time dependent-density functional theory (DFT/TD-DFT) computations were performed at M06/6-311G(d,p) functional. The geometry, electrical and optical properties of the designed acceptor molecules were compared with reported IBR architecture. Interestingly, a reduction in bandgap (2.528-2.126 eV), with a broader absorption spectrum, was studied in IBR derivatives (2.734 eV). Additionally, frontier molecular orbital findings revealed an excellent transfer of charge from donor to terminal acceptors and the central indenoindene-core was considered responsible for the charge transfer. Among all the chromophores, IBRD3 manifested the lowest energy gap (2.126 eV) with higher λ_max at 734 and 745 nm in gaseous phase and solvent (chloroform), respectively due to the strong electron-withdrawing effect of five end-capped cyano groups present on the terminal acceptor. The transition density matrix map revealed an excellent charge transfer from donor to terminal acceptors. Further, to investigate the charge transfer and open-circuit voltage (V_oc), PBDBT donor polymer was blended with acceptor chromophores, and a significant V_oc (0.696-1.854 V) was observed. Intriguingly, all compounds exhibited lower reorganization and binding energy with a higher exciton dissociation in an excited state. This investigation indicates that these designed chromophores can serve as excellent electron acceptor molecules in organic solar cells (OSCs) that make them attractive candidates for the development of scalable and inexpensive optoelectronic devices.

Abstract

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