A Naphthodithiophene-Diketopyrrolopyrrole Donor Molecule for Efficient Solution-Processed Solar Cells

Abstract
We report the synthesis, characterization, and first implementation of a naphtho[2,3-b:6,7-b′]dithiophene (NDT)-based donor molecule in highly efficient organic photovoltaics (OPVs). When NDT(TDPP)2 (TDPP = thiophene-capped diketopyrrolopyrrole) is combined with the electron acceptor PC61BM, a power conversion efficiency (PCE) of 4.06 ± 0.06% is achieved—a record for a PC61BM-based small-molecule OPV. The substantial PCE is attributed to the broad, high oscillator strength visible absorption, the ordered molecular packing, and an exceptional hole mobility of NDT(TDPP)2.