Theoretical Design of High-Performance Boron Dipyrromethenes Dyes by Introducing Heterocyclics to Tune Photoelectric Properties

As a "sister" of porphyrins, boron dipyrromethenes (BODIPY) have attracted widespread attention because of their strong absorption in the visible region. Although many modifications have been made to its structure, the photoelectric conversion efficiency (PCE) below 10% limits its practical application in dye-sensitized solar cells (DSSCs). In this work, heterocycles were introduced into the BODIPY pi-bridge to improve the photoelectric properties of dyes. Theoretical calculations show that the introduction of heterocycles, such as cyclopentadiene, pyrrole, furan, and thiophene, not only increases the molecular planarity and narrows the band gap but also enhances the light harvesting ability. Based on these exciting results, the dye/(TiO2)(38) adsorption models and parameters related to DSSC performance including short-circuit current, open circuit voltage, and PCE were considered to evaluate the overall properties of the investigated dyes. These dyes achieve a PCE value of at least 15.25%, wherein the PCE value of dye inserted thiophene into BODIPY can be as high as 23.12%, which are expected to have potential application in DSSC devices.