Photovoltaic and Optical Characterization of Organic Heterocyclic 6,6′‐Dibromoindigotin Crystal Under Changing Solvent Polarity by DFT Analysis

Abstract

The photovoltaic and optical properties of 6,6′‐dibromoindigotin (DBI) crystal under changing solvent polarity are investigated through DFT analysis. It includes geometry optimization, global reactivity, UV–vis analysis, open circuit voltage (Voc), FMOs, and NBO analysis. The highest HOMO‐LUMO gap (Egap) value is found for the gaseous phase (1.82 eV), while the lowest Egap is found for dichloro methane (1.64 eV), and intermediate values with the other solvents. The molecule has a high IP of 2.48 eV, low EA of 0.74 eV, moderate polarity, and hardness (η). The maximum absorption wavelengths (λmax) of the compound in different solvents are dichloromethane and DMSO (373 nm), chloroform (372 nm), methanol and water (371 nm), toluene (367 nm), and gaseous (356 nm). Their Voc range is 0.2–0.28 eV. Among all, chloroform demonstrates the highest performance with a fill factor (FF) of 0.8630, normalized open circuit (Nor. Voc) of 31.69 eV, and Jsc of 26.47 mA cm−2. Toluene also shows promising results with an FF of 0.8060, Nor. Voc of 19.71 eV, and Jsc of 21.19 mA cm−2. Water, although not as effective as other solvents, still exhibits respectable values with an FF of 0.8315, Nor. Voc of 23.96 eV, and Jsc of 24.63 mA cm−2.