Thiophene Modulated BODIPY Dye as a Light Harvester

A new BODIPY dye with terthiophene branched is configured by Sonogashira coupling and fully characterized by NMR and MS. In general organic solvents, it emits typical green fluorescence ranging in 513-518 nm, like most BODIPY analogues. The terthiophene substitution is greatly improved and the emission peak does not sensitive to the polarity environment. More importantly, the terthiophene plays the role of antenna, harvesting the 340 nm's excitation energy and transferring the energy to BODIPY efficiently. Even though the molar extinction coefficient in 340 nm is lower than that of maximum absorption, it can enlarge the pseudo Stoke's shift to similar to 170 nm, well separating the excitation and emission. In film, the emission shifted to 562 nm due to the polymer chain dissipation part of the energy. It shifted further to 585 nm in solid. The branched terthiophene configures a twisted molecular conformation, which avoids the dye regular packing. Highly emission, excellent solubility and stability constitute the general character of the thiophene attached BIDIPY dye.