Structural and optoelectronic analysis of a novel perylene diimide as a light-harvesting material for dye-sensitized solar cells

Perylene diimides (PDIs) have emerged as an excellent n-type semiconductor substitute for fullerenes in energy devices. A novel PDI, N, N′-bis-(2-phenylethyl)-3,4,9,10-perylene bis(dicarboximide)(PDEA), was synthesized and its structure was thoroughly characterized using Fourier transforms infrared spectroscopy (FTIR), High-resolution mass spectroscopy (HRMS), Proton Nuclear magnetic resonance (¹H NMR). The optical properties of the PDI were evaluated using UV–visible, and Photoluminescence (PL) spectroscopic techniques. The UV–Visible spectrum of PDEA exhibited a broad absorption band in the visible range (400–800 nm), with yellowish-green fluorescence emission under a UV lamp. The structure of PDEA was optimized using Density Functional Theory (DFT) with the B3LYP/6-31G (d, p) basis set, and its optoelectronic properties were evaluated in a variety of solvents of different polarities. Further, Cyclic Voltammetry (CV) was utilized to examine the electrochemical redox behaviour of PDEA in acetonitrile which was observed to be one-electron quasi-reversible. The as-synthesized PDEA was used to fabricate the DSSC and was found to exhibit a good photovoltaic performance with a fill factor (FF) of 72, an open-circuit voltage (V_oc) of 0.52 V, a PCE (power conversion efficiency) of 0.63 %, and a Jsc (short circuit current density) of 1.67 mA/cm². The above-mentioned characteristics of the PDEA may have applications in photovoltaics, fluorescence-based detectors, n-channel field-effect transistors, and other related areas.