Controlling length-scales of the phase separation to optimize organic semiconductor blends

The length-scale of phase separation in organic semiconductor donor-acceptor mixtures, while being crucially important for applications, is a non-trivial parameter to control in non-equilibrium thin film growth. We present a comprehensive study of all the important parameters that can be used to tailor the length-scale of phase separation in organic semiconductor mixtures. We employed different substrate temperatures, different growth rates, time-dependent deposition rates, and surface functionalization layers. We found not only that the substrate temperature is most prominent in influencing the length-scale of phase separation in the studied parameter range, but also that other routes can be used to tailor this length-scale.