PhD ceremony: Mr. D.J.D. Moet, 13.15 uur, Doopsgezinde kerk, Oude Boteringestraat 33, Groningen
Dissertation: Enhanced performance of single and double junction plastic solar cells
Promotor(s): prof. P.W.M. Blom
Faculty: Mathematics and Natural Sciences
In the most efficient plastic solar cells to date, sunlight is absorbed in an ultrathin layer of a semiconducting polymer mixed with an n-type organic material. Collected photons are directly converted into electricity via the complex processes of generation, dissociation, transport and extraction of electric charges. The power conversion efficiency of plastic solar cells strongly depends on the optical and electronic properties of the utilized polymer. In many cases, the performance is limited due to impediments in one or more of the processes mentioned above.
This work studies the device physical origin of such performance limitations for various polymer-based photovoltaic systems and discusses how these can be minimized. Based on experimental characterization and device modeling, it is shown how molecular weight, choice of processing solvent and chemical side-reactions during fabrication can affect the operation of single-layer plastic solar cells.
Moreover, we show that in specific cases optical and electronic losses can be reduced simultaneously by using a device structure with two photoactive layers. Careful design of the required middle electrode enables such double junction cells to show enhanced performance compared to optimized single layer devices. These results and the outcome of extensive optoelectronic modeling path the way towards efficient solution-processed tandem polymer solar cells that contain two complementary absorbing photoactive layers.
How is it possible that an albatross doesn’t crash and die when it lands? And how come its large wings don’t break due to air resistance? That is what you would expect, according to the laws of aerodynamics. However, Professor Eize Stamhuis has discovered...
In contrast to popular belief, lightning often does strike twice, but the reason why a lightning channel is ‘reused’ has remained a mystery. Now, an international research team led by the University of Groningen has used the LOFAR radio telescope to...
On March 29th professor of Applied Physics Jeff de Hosson was offered a farewell symposium, a few months after his official retirement date near the close of 2018. ‘But 29 March was the 100th birthday of Jan Francken, my predecessor.’ Besides, De Hosson...