Design, Synthesis and Functionalization of BODIPY dyes: Applications in Dye-Sensitized Solar Cell (DSSC) and Photodynamic Therapy (PDT)

In recent years, BODIPY dyes have emerged as a valuable category of luminogens for optoelectronic applications because of their spectacular properties, such as good fluorescence quantum yield, broad absorption with high molar extinction coefficient, excellent photo-chemical and thermal stability, remarkable redox properties, easy structural modifications and good solubility. These properties of BODIPY dyes make them an important class of chromophores for application in nonlinear optics, dye-sensitized solar cells, chemosensors, photodynamic therapy, bioimaging, electron-transporting materials, ultrafast charge transfer, perovskite solar cells and many more. BODIPY dyes have three main reactive sites: α-, β-pyrrolic and meso positions, which enable modifications for the synthesis of various donor–acceptor BODIPY dyes. BODIPY derivatives that exhibit high thermal and photostability, low-cost production, strong NIR absorption/emission and a low bandgap have been explored for photovoltaic and biomedical applications. In this review, we discuss the synthesis, functionalization, and various reactions, such as Pd-catalyzed cross-coupling reactions, Grignard reactions, the Knoevenagel reaction and many more, at the α-, β-pyrrolic and meso positions of the BODIPY core and the application of BODIPY dyes in dye-sensitized solar cells and photodynamic therapy.