Lecture Elizabeth von Hauff
|22 June 2012||FWN-Building 5118.-152, Nijenborgh 4, 9747 AG, Groningen|
|Speaker:||Prof. Dr. Elizabeth von Hauff|
|Affiliation:||Organic Photovoltaics & Electronics Group, Institute of Physics, University of Freiburg and Fraunhofer ISE, Freiburg (Germany)|
|Title:||The influence of molecular doping on low bandgap polymers in bulk heterojunction solar cells|
|Date:||Fri Jun 22, 2012|
|Host:||Jan Anton Koster|
|Telephone:||+31 50 363 4928/8750 (secr)|
Solar cells based on polymer: fullerene bulkheterojunctions (BHJ) offer a promising technology for flexible, large area photovoltaic applications. The active layer in the BHJ is comprised of a soluble conjugated polymer mixed with a soluble fullerene derivative to create an interpenetrated network of donor and acceptor domains at the nanoscale, with the dual purpose of maximizing the interface between donor and acceptor and efficiently transporting charge to the contacts. In the BHJ transport and recombination are a delicate interplay between morphology and carrier lifetime/mobility. A lot of work has been done in the literature to optimize blend morphology, but low charge carrier mobilities in solution processed organic semiconductors represent a fundamental limitation for the photocurrent.
The design of conjugated polymers with low bandgaps lying in the near infrared has improved the light harvesting properties. The hole mobility in the polymer phase remains a limiting factor for achieving high photocurrents, and novel strategies to further improve the transport properties of the donor material are needed. Molecular doping the blend with the electron acceptor F4-TNCQ at low concentrations can be an efficient method to improve hole mobility, reduce recombination, and enhance the photocurrent in solar cells based on the low bandgap polymer PCPDTBT. In this talk the influence of F4-TCNQ on the properties of PCPDTBT layers is discussed.
|Last modified:||22 October 2012 2.30 p.m.|