A-D-A Type Small Molecules Based on Boron Dipyrromethene for Solution-Processed Organic Solar Cells

The unique properties of boron dipyrromethene (BODIPY) dyes including facile synthesis, high absorption coefficients, and delocalized molecular orbitals as well as excellent photochemical and thermal stability, make them promising as materials for organic solar cells. Accordingly, in this study three A-D-A structural small molecules of BDTT-BODIPY, FL-BODIPY, and TT-BODIPY have been synthesized, in which two BODIPY acceptor units are symmetrically conjugated to 4,8-bis(5-(2-ethylhexyl) thiophen-2-yl)benzo[1,2-b:4,5-b]dithiophene (BDTT), 9,9-dioctyl-9H-fluorene (FL), and thieno[3,2-b]thiophene (TT) donor cores, respectively. The manipulation of the structural parameters significantly improves the performances of the BHJ OSCs, which show power conversion efficiencies of 4.75 , 1.51 , and 1.67 based on [6,6]-phenyl C₇₁-butyric acid methyl ester (PC₇₁BM) as the acceptor material and BDTT-BODIPY, FL-BODIPY, and TT-BODIPY as the donor materials, respectively. Type A-D-A personality: Three A-D-A type small molecules based on BODIPY have been synthesized for solution-processed organic solar cells, in which the best power conversion efficiency is up to 4.75 , demonstrating that BODIPY is promising for the development of efficient organic solar cells.