Efficient Benzodithiophene/Benzothiadiazole‐Based n‐Channel Charge Transporters

A series of donor–acceptor (D‐A) small molecules based on electron‐deficient benzothiadiazole (BTD) and electron‐rich benzodithiophene (BDT) featuring an A‐D‐A structure is presented. Exhaustive spectroscopic, electrochemical, and computational studies evidence their electroactive nature and their ability to form well‐ordered thin films with broad visible absorptions and low band gaps (ca. 2 eV). Time‐resolved microwave conductivity (TRMC) studies unveil unexpected n‐type charge transport displaying high electron mobilities around 0.1 cm2 V−1 s−1. Efficient electron transport properties are consistent with the low electron reorganization energies (0.11–0.17 eV) theoretically predicted. Getting electrons on the move: Acceptor‐donor‐acceptor triads based on benzothiadiazole and benzodithiophene moieties show unprecedented high electron mobilities (0.1 cm2 V−1 s−1) for these sort of low band‐gap (2.0 eV) materials (see figure). These experimental findings are explained by the calculated low reorganization energies and the good quality of the film.