A Very Low Band Gap Diketopyrrolopyrrole–Porphyrin Conjugated Polymer

Abstract

A porphyrin-diketopyrrolopyrrole-containing polymer (poly(porphyrin-diketopyrrolopyrrole) (PPDPP)) shows impressive molar absorption coefficients from λ=300 to 1000 nm. The photophysical and structural properties of PPDPP have been studied. With PPDPP as the electron donor and [6,6]-phenyl C₇₁ butyric acid methyl ester (PC₇₁ BM) as the electron acceptor, the bulk heterojunction polymer solar cell showed overall power conversion efficiencies of 4.18 and 6.44 % for as-cast and two-step annealing processed PPDPP:PC₇₁ BM (1:2) active layers, respectively. These results are quite impressive for porphyrin-containing polymers, especially when directly included in the π-conjugated backbone, and offer interesting perspectives for the design of new materials based on this chromophore.