Computational design of BODIPY-based donor-acceptor-donor molecules for enhanced organic solar cells: A DFT and TD-DFT study

Developing donor-acceptor-donor (D-A-D) molecular structures is essential in advancing organic solar cell technology due to their ability to enhance photovoltaic performance. Recently, Ting Wei and colleagues synthesized a small molecular D-A-D structure (BP-R) derived from the BODIPY skeleton and demonstrated its effectiveness in organic solar cells. Inspired by this work, we designed new BODIPY-based D-A-D structures and computationally evaluated the effect of the new electron-donating units. The structures developed in this work consist of the central BODIPY core, which is attached to the electron-donating groups of cyclopentadithiophene (CPDT), dithieno[3,2-b:2′,3′-d]pyrrole (DTP), and dithienosilole (DTS) from positions 3,5 and 8. We analyzed the optical and electronic properties of these new structures using Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT). Compared with BP-R, our designed molecules showed lower energy gaps, red-shifted absorption spectra, and improved light harvesting efficiency, and BP-DTS emerged as the most promising candidate. This study paves the way for the rational design of advanced BODIPY-based materials to optimize the efficiency and stability of organic solar cells.