Thin films comprising a blend of electron donating and electron accepting molecules are ubiquitous in organic opto-electronic devices. At the donor-acceptor interfaces, intermolecular charge-transfer (CT) states form, in which an electron is transferred from donor to acceptor. Electrical doping involves CT in the ground-state, from dopant to host, and results in increased conductivities of the host organic semiconductor. Furthermore, efficient photo-induced charge generation in organic materials depends crucially on donor-acceptor interfaces where the CT state is an excited state. Organic electronics will in the future enable new applications for a healthy, green and connected society, such as for example low-cost, non-toxic and building integrated and indoor photovoltaics, efficient light sources, sensors for healthcare or artificial synapses. However, current progress is hampered by a lack of understanding of the fundamental properties of intermolecular CT states and their dissociation and decay mechanisms. Improving performance of devices is nowadays often based on time consuming rail-and-error methods. The objective of ConTROL is to fill the knowledge gap and link device performance to CT state properties and molecular parameters of donor and acceptor. Besides the established way of tuning electro-optical properties by molecular design and appropriate donor-acceptor selection, innovation in ConTROL lies in the use of weak and strong interactions with the opto-electronic device’s optical cavity. The newly developed models and simulation code taking these effects into account, from the molecular to the device level. The project will demonstrate rational design of new organic semiconductors resulting in improved performance of organic electronic applications, as well as novel device concepts for sensing and energy conversion based on donor-acceptor blends.
