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Thursday, 17 Oct 2024 |
Video-Recording for any system with MP4-support - Video.mp4 (ca. 450 Mb) |
15:15 – 16:25 |
"What’s
new under the Sun? Solar cells built from solution"
Prof. Ellen Moons
(Karlstad
University)
Abstract:
Solar cells are made of semiconductors
that absorb light and convert it to electricity.
Inorganic solar cells, based on
semiconductors like silicon and gallium arsenide,
are prepared with great care in clean-room
conditions and show power conversion
efficiencies above 25% and long
operational lifetimes. Thin film technologies use
smaller amounts of semiconducting material
deposited on a transparent conducting
substrate by vacuum deposition techniques.
Two new classes of solar cell materials
that have been a focus of PV research
during the last 20 years are organic and
halide perovskite solar cells. Both are
processed from solutions at room temperature.
Organic solar cells (OSC) are a promising,
low-cost, emerging renewable energy
technology based on electron donating and
electron accepting molecules forming
a photoactive layer with a distributed
heterojunction. OSCs have achieved record
power conversion efficiencies approaching
20%. Besides the power efficiency,
advantages such as flexibility,
transparency, light weight, and inexpensive large area
production strengthen their commercial
perspective. The improvement in performance
can be ascribed to the replacement of
fullerene derivatives by new electron acceptors,
called non-fullerene acceptors (NFA),
which contribute to light absorption in the
visible range and consequently to the
charge generation. Besides their advantages,
NFAs also bring challenges for the
processing of the photoactive layers from solution,
due to their limited solubility in
commonly used organic solvents.
Some of the research topics in this field
are: 1) the control of the donor-acceptor bulk heterojunction (BHJ) morphology
and the understanding of the photophysics that
determine the OSC performance; 2) the understanding
of degradation processes of
the molecular materials to improve the
photostability of the OSCs, and 3) the
transition to more environmentally
friendly solvents in the fabrication of OSCs.
About the Speaker:
Ellen Moons is an experimental materials
physicist and leads a research group at
Karlstad university focussed on scanning
probe microscopy and soft X-ray
spectroscopy of solution-processed
materials for organic and perovskite solar cells.
She received her Physics degree from the
University of Ghent in Belgium, and her
PhD degree from the Weizmann Institute of
Science in Israel in 1995.
After post-doctoral research stays at
Delft University of Technology,
École Polytechnique Fédérale de Lausanne,
and University of Cambridge,
and an appointment as research scientist
at Cambridge Display Technology Ltd,
she joined Karlstad University in Sweden
as assistant professor. In 2011 she was
promoted to Professor of Physics at
Karlstad University. She was awarded the
Göran Gustafsson prize for Physics in 2011
for her work on organic solar cells
and was elected member of the Swedish
Royal Academy of Sciences in 2017.