Efficient tuning of small acceptor chromophores with A1-π-A2-π-A1 configuration for high efficacy of organic solar cells via end group manipulation

Abstract

Now a days, non-fullerene organic compounds are considered with keen interest for the greener energy and potential photovoltaic devices. Herein, novel acceptor chromophores (DPDVD1-DPDVD4) were designed via small acceptor DPDVR compound with A1-π-A2-π-A1 architecture using promising approach by redistribution of end-capped acceptor moieties. The effect of end-capped acceptor moieties on designed architecture for the photophysical, photovoltaic and electronic behavior was explored using quantum chemical study. Frontier molecular orbital (FMO) findings revealed that all the molecules (DPDVD1-DPDVD4) contained narrow band gaps. The central acceptor moiety (PzDP) was responsible for the transformation of charge in DPDVD1-DPDVD4. UV–Vis data disclosed that λmax values of DPDVD1-DPDVD4 compounds were existed in visible region (537.36–517.05 nm). Interestingly, DPDVD2 exhibited the reduced band gap with broader absorption spectra among all chromophores might be due to the negative inductive effect (−I) of the terminal acceptors. The open circuit voltage (Voc) analysis was performed at the interface between standard donor polymer (PTB7) and DPDVD2. The higher value (3.34 V) of Voc was observed for DPDVD2 among reference and designed compounds. Furthermore, reorganization energy findings exploited DPDVR-DPDVD4 shown lower values of λe than λh which indicated that these chromophores were the promising candidates for electron transportation mobilities. The larger charge mobilities with greater exciton dissociation in excited state for DPDVD2 were examined, subsequently this compound showed minimum value of λe (0.015739 eV) among all chromophores. Detailed studies reveal that the entitled molecules can behave as efficient electron acceptor molecules in organic solar cells (OSCs) that make them interesting candidates for the development of inexpensive optoelectronic devices.