Blade coating of diketopyrrolopyrrole based organic photovoltaics from non-halogenated solvent systems

The need for scalable and environmentally friendly deposition of organic semiconductors is mounting, as lab-scale solution processed organic photovoltaic (OPV) devices have been certified with 10.8% efficiency. The replacement of toxic halogenated solvents is a priority in the commercialization of solution processed OPV. Here we introduce several solvent systems based on thiophene, tetraline, 1,2,4-trimethylbenzene, xylene, and anisole for the blade coating of diketopyrrolopyrrole-based polymer: fullerene OPV devices. These devices attain 6.1% efficiency, greater than the commonly used chloroform:ortho-dichlorobenzene solvent systems for the same polymers, and without involving the post-deposition annealing treatments nor additives typically implemented for non-halogenated inks. Furthermore, the solubility of the material was investigated with Hansen Solubility Parameters, and coatability on a variety of substrates was probed via contact angle measurements. This work enables a new non-halogenated solvent route for the scalable fabrication of organic electronics.