• Marcom Conference Web banner

Invited SpeakersProfile Details

Dr. Koen Vandewal
Dr. Koen Vandewal Prof. Dr. Koen Vandewal was appointed as Endowed Professor in 2014 at the Technische Universitaet (TU) Dresden in Germany, where he led a research group which aimed to solve fundamental questions in the field of organic and molecular electronics with relevance to applications in opto-electronic devices such as organic light-emitting diodes, organic solar cells and sensors.

Biography

​Prof. Dr. Koen Vandewal (23-06-1981) obtained his PhD in Physics at Hasselt University in 2009 under the supervision of Prof. Dr. Jean V. Manca, working on the physics of organic photovoltaics. After that, he has been working for two years as a Postdoctoral Fellow at Linkoping University in Sweden and another two years at Stanford University in the US.

In 2014, he was appointed as Endowed Professor at the Technische Universitaet (TU) Dresden in Germany, where he led a research group which aimed to solve fundamental questions in the field of organic and molecular electronics with relevance to applications in opto-electronic devices such as organic light-emitting diodes, organic solar cells and sensors. In January 2018, Prof. Vandewal took a position in Insitute for Materials Research, Hasselt University.

In the organic electronics community he is best known for his seminal work on charge-transfer states at organic interfaces and their role in photovoltaic devices.

All sessions by Dr. Koen Vandewal

  • Day 1Sunday, February 25th
Workshop
12:45 pm

Charge Recombination and the Open-Circuit Voltage of Solar Cells

Most photovoltaic technologies exhibit high photon-to-charge-carrier conversion yields, approaching 90%-100%. However, a solar cell only generates power when an additional photo-voltage is produced. This photo-voltage is ideally as close as possible to the open-circuit voltage (Voc) of the device. When a solar cell is held at open-circuit, no charges flow in the external circuit, hence they all recombine within the photovoltaic material. Suppressing the recombination of charge carriers will result in increased Voc and power conversion efficiencies. Recombination can result in the emission of a photon or can occur non-radiatively, with the former being unavoidable and thus limiting Voc. In this lecture, we will consider general relations between photon absorption, emission and photovoltaic action, valid for established and emerging photovoltaic technologies. We will derive upper limits for Voc and summarize strategies to suppress recombination and reach those limits. Organic photovoltaics, where charge-transfer states between electron donating and accepting materials play a crucial role, will be discussed in more detail.

Auditorium between Building 4 and 5 12:45 - 13:45 Details