Syntheses, DFT studies and comparatively photovoltaic applications of some pyrene-imine hybrid derivatives

Abstract

In this study, (E)-N-phenyl-1(pyren-1yl)methanimine (3) and a isomeric mixture of 5ZZ and 5EE (1,4-phenylenebis(1-(pyren-1-yl)methanimine) were synthesized by condensation of pyrene-1-carbaldehyde (1) with aniline (2) or benzene-1,4-diamine (4) The synthesized compounds were characterized using NMR, UV–vis, IR and HRMS spectroscopic techniques.Utilizing the density functional theory (DFT) and a basis set of B3LYP/6-311G(2d,2p), theoretical computations were done. The computed values were applied to simulated spectra of compounds 3 and the isomeric mixtures 5EE, and 5ZZ demonstrating good agreement with observed spectra. In various solvents, the UV–vis spectra of compounds 3, 5EE, and 5ZZ were recorded in areas 200–500 nm, and function density theory (DFT) and time-dependent density functional theory (TD-DFT) algorithms were used to determine if they can serve as metal-free organic dyes in the use of dye-sensitized solar cells (DSSCs). The charge separation distance (Δr) between an electron and the hole it corresponds to was investigated in addition to the degree of electron-hole overlap (Λ) because transition density matrices (TDM) give information about how each electron departs from its corresponding hole during excitations, resulting in charge transfer (CT). To obtain more insight into the characteristics of complexes, the Mulliken population approach, density of states (TDOS), natural population analysis (NPA), molecular electrostatic potential (MEP), condensed Fukui function, and relative nucleophilicity indices derived from orbital charge calculation results (NPA) were used. In addition, the photovoltaic properties of these compounds were studied comparatively. DFT band gap for 3 was 2.493, 5EE was 2.050, and 5ZZ was 2.071 eV. Furthermore, the power conversion efficiency (PCE) values for compound 3 and the isomeric mixture of compound 5 are calculated as 2.31%, and 2.82%, respectively. The results obtained can provide a useful reference for the development of organic compounds containing pyrene units in more efficient organic-based compounds for photovoltaic applications.