On November 9th the Institute for Energy Efficiency will sponsor a lecture by Dr. Koen Vandewal. He obtained his PhD. in Physics at Hasselt University in 2009 under the supervision of Professor Dr. Jean V. Manca, working on the physics of organic photovoltaics.
The abstract for this lecture is as follows: “Intermolecular charge transfer (CT) states at the interface between electron-donating and electron-accepting (A) materials in organic thin films are characterized by absorption and emission bands within the optical gap of the interfacing materials. Depending on the used donor and acceptor materials, CT states can be very emissive, or generate free carriers at high yield. The former can result in rather efficient organic light emitting diodes, via thermally activated delayed fluorescence, while the latter property is exploited in organic photovoltaic devices and photodetectors. In this contribution, we will discuss the fundamental properties of CT states and link them to organic opto-electronic device performance; with a special focus on organic solar cells. We explore possibilities for increasing the operating voltage and discuss the influence of the donor-acceptor interfacial area, electronic coupling, and molecular reorganization. Furthermore, we introduce a new device concept, using an optical cavity resonance effect to boost CT absorption at photon energies below the optical gap of both donor and acceptor, enabling narrow-band, near-infrared (NIR) photo-detection.”