meso-Diphenylbacteriochlorins: Macrocyclic Dyes with Rare Colors for Dye-Sensitized Solar Cells

We herein report the synthesis, UV–vis absorption, fluorescence emission, and redox properties of three novel meso-diphenylbacteriochlorins. Significantly, we show that substituents at the meso-positions of an air-stable bacteriochlorin can be manipulated for the first time. With proper design, this allows tailor-made bacteriochlorins to exhibit suitable properties for a chosen application. As an example, photovoltaic properties of two such bacteriochlorins in dye-sensitized solar cells are investigated. The results show that the bacteriochlorin dyes outperform a reference porphyrin dye. Intriguingly, the anodes sensitized with the new dyes display rare colors—blue and pink.