Transcript Small Molecule Organic Photovoltaic Cells : The Importance of Controlling Interface Properties

Department of Chemistry
Seminar Announcement
Date/Time/Venue
Title/Speaker
11 Jan (Tue)
11am – 12nn
Small Molecule Organic Photovoltaic Cells :
The Importance of Controlling Interface
Properties
@ S8 Level 3
Executive
Classroom
Professor Tim Jones
University of Warwick, UK
Host : Asst Prof Chen Wei
About the Speaker
Professor Tim Jones obtained his B.Sc. and Ph.D. from the University
of Liverpool-UK in 1985 and 1988 respectively. He began his career as
a postdoctoral research assistant in the same university. In 1991, he
joined Imperial College London as a lecturer and was promoted to
professor in 1998. He was also the Head of Electronic Materials
Section, from 1997 to 1999, director of the Centre for Electronic
Materials and Devices from 2000 to 2006 and a co-director of London
Centre for Nanotechnology from 2002 to 2007. In 2007, he joined the
University of Warwick as a professor. He became the Head (Department of
Chemistry), University of Warwick from 2008 to 2010, Deputy Chair of the Faculty of
Science from 2007 to 2010 and was promoted to Chair of the Faculty of Science in
2010. He is currently the Pro-Vice Chancellor for Knowledge Transfer and Business
Engagement.
Abstract
Organic photovoltaic (OPV) cells based on donor-acceptor heterojunctions have the
potential of being low-cost, lightweight and flexible. Current state-of-the-art cells based on
polymer/molecule or molecule/molecule heterojunctions exhibit power conversion
efficiencies of ca. 5-7% and it is widely recognised that significant improvements in
performance will be required to allow the technology to become commercially viable. The
overall efficiency of OPV cells is proportional to the short circuit current density, the open
circuit voltage and the fill factor. However, in order to optimise each of these key device
parameters a rigorous understanding of the underpinning science is essential. Small
molecule planar heterojunction cells are particularly well suited for the study of such
fundamental parameters since their fabrication using high vacuum organic molecule beam
deposition provides precise control of device architecture, as well as compatibility with insitu diagnostic techniques for probing surface and interface properties.
In this talk I will focus on some of the key factors that influence the performance of small
molecule OPV cells based on materials such as phthalocyanines, oligoacenes, perylenes
and fullerenes. In particular I will emphasise the importance of understanding and
controlling interfacial properties, both at the donor-acceptor organic heterojunction and
also at the junction between the electrodes and the organic layers. Our recent work on the
insertion of ultra-thin metal oxide and organic interlayers at the interface between the
transparent conducting hole extracting electrode and different organic donor layers will be
highlighted and promising routes for further improvement in the performance of these cells
will be presented. Finally I will present recent results on the development of multi-junction
OPV cells which offer excellent prospects for realising the levels of performance required
for ultimate commercialisation.
All are Welcome