Eur. Phys. J. Plus (2022) 137: 456
https://doi.org/10.1140/epjp/s13360-022-02595-w

Regular Article

First example of N-shaped dipyrrolo[2,3-b:2′,3′-e]pyrazine-2,6(1H,5H)-dione based small acceptor materials: Role of cyano (−C≡N) free guest acceptors for developing environmental friendly organic solar cells

¹ Department of Chemistry, University of Okara, 56300, Okara, Pakistan
² Department of Management Sciences, COMSATS University Islamabad, Islamabad, Pakistan
³ Department of Chemistry, Faculty of Science, King Khalid University, P.O. Box 9004, 61413, Abha, Saudi Arabia

^b usm1_alvi@hotmail.com
^d usman.chemistry@gmail.com, usmankhan@uo.edu.pk

Received: 28 August 2021
Accepted: 13 March 2022
Published online: 11 April 2022

Abstract

Herein, we planned to architect novel N-shaped environmental friendly organic solar cells (EFOSCs) based on dipyrrolo [2,3-b:20,30-e]pyrazine-2,6 (1H,5H)-dione (PzDP) type DPDV molecule. The cyano (−C≡N) group of 4,5-dicyano-2-vinyl imidazole (vinazene) present as end-capped acceptor in DPDV is replaced with non-toxic electron-withdrawing groups −CF₃, −SO₃H, −NO₂ and series (DPDV-1 to DPDV-6) of N-shaped novel photovoltaic materials are quantum chemically designed. A detail density functional theory (DFT) and time-dependent DFT (TDDFT) assisted structure–property relationship has been studied to explore photovoltaic, photophysical, and optoelectronic properties of environmental friendly proposed N-shaped molecules (DPDV-1 to DPDV-6). Transition density matrix (TDM) heat maps, open-circuit voltage (V_oc), exciton binding energy (E_b), transition energy (E_x), hole and electron reorganization energy (λ_h, λ_e), UV–Visible, density of state (DOS), overlap DOS (ODOS) and PTB7-donor polymer-based charge transfer analysis have been executed. Results confirmed that  −C≡N free −CF₃, −SO₃H, −NO₂ based-environmental friendly proposed compounds exhibited better and comparable results to  − C≡N based (vinazene) reference compound. N-shaped developed molecules (DPDV-1 to DPDV-6) exhibited red-shift an absorption maximum in the span of 523–566 nm. The lowest electron mobility and binding energy values 0.0003 eV, 1.64 eV respectively are represented by DPDV-2. The lowest hole mobility value 0.003 eV is given by DPDV-4. Proficient hole, electron reorganization energy values, and successful charge transfer in HOMO_PTB7-LUMO_Acceptor film confirm the utilization of developed compounds in organic solar cell (OSC) films. All results proved that developed molecules not only better to synthesized compound in terms of optoelectronic features but also holds environmental friendly characteristics. This theoretical insight will offer an effective  −C≡N-free strategy to develop future EFOSCs along with novel N-shaped environmental friendly materials for OSCs applications.