Sequestration of electroactive materials in a high Tg, insulating polymer matrix for optoelectronic applications. Part 2. Photovoltaic devices

The incorporation of high levels of electroactive compounds into a high Tg matrix polymer was investigated in photovoltaic (PV) devices. The combination of electron donor-electron acceptor pairs with optionally light harvesting organics (e.g. laser dyes) in the high Tg polymer matrix yielded PV performance in the range of literature data typically reported for organic based PV devices. The advantages for using a high Tg matrix include increasing the Tg of the electroactive compounds, preventing crystallization, improving the mechanical properties of the active layer(s) and the ability to employ lower cost fabrication processes. While the basic concept has been demonstrated, further optimization would be required to achieve a useful combination of photovoltaic properties. As in the companion paper on utilization of a high Tg polymer to sequester low molecular weight electroactive species for LED devices, this paper demonstrates the same concept for PV devices. The approach to solve the issues with low molecular weight electroactive species noted in the literature to date often involves covalent bonding of these compounds to polymeric backbones. This and the companion paper well-illustrates the blend approach is equally viable and offers a much simpler methodology.