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S U S T A I N A B I L I T Y
R E S E A R C H @ H K U S
Organic Solar Cells
On the solar energy front, the current
focus at HKUST is on organic and hybrid
organic-inorganic solar cells that could
outperform traditional solar cells at a
lower cost. Cross-disciplinary research
combines novel materials development
and nano-scale device engineering to en-
hance efficiency and durability of the so-
lar cells. To reduce production cost, flexi-
ble thin-film organic solar cells are being
developed that would take advantage of
high-speed manufacturing processes.
Breakthrough records in the effi-
ciency of organic solar cells have been
achieved by Prof Henry Yan and his group
in the Department of Chemistry. Organic
solar cells offer a flexible alternative to
the conventional rigid inorganic solar
cells that make up today’s solar panels.
The advantages of organic solar cells
include faster and cheaper mass produc-
tion processes due to their flexibility,
including roll-to-roll printing similar to
newspaper production. These solar cells
are also light in weight and environmen-
tally friendly. Such features open up inte-
grated applications for windows, build-
ings, vehicles, and for charging mobile
devices, such as smartphones, among
others. Different shapes and colors add to
commercialization potential.
The major challenge is to improve
performance. While today’s inorganic
silicon crystalline solar cell has power
conversion efficiency of around 20%,
most published research results for
organic solar cells remain at around 10%,
which is still not sufficient forwide-spread
commercial applications.
Through observation of a significant
material motif that has enabled a novel
method of controlling the morphology –
Temperature-dependent
aggregation enables
ideal morphology
The polymer solution
is not aggregated at
high temperatures, but
strongly aggregated at
room temperature. This
unique property allowed
HKUST researchers to
achieve multiple cases
of record efficiency
organic solar cells.
the mixing – of materials in the solar cell
based on temperature control, Prof Yan
has made a major stride in this global race
by achieving record-breaking efficiency
for single-junction organic solar cells of up
to 11.5%. For the first time, Hong Kong re-
search has been featured in the US-based
National Renewable Energy Laboratory
(NREL) table – an authoritative record of
data from around the globe on the best
research cell efficiencies. These findings
have also appeared in
Nature Communi-
cations
(2014) and
Nature Energy
(2016).
Prof Yan and his group have also de-
veloped a “family” of polymer and fuller-
The HKUST Energy Institute is a leading
international center for energy research
and education, with a reputation for
excellence across a broad range of
fields, which includes sustainable
energy generation, storage, distribution
and utilization. It is a multidisciplinary
platform for integrating, facilitating and
enabling University-wide programs in
energy-related research, development
and education.
Building on HKUST’s existing research
strengths, the Institute strives to provide
a strong and visible leadership role
in energy research in Hong Kong, as
well as to engage in emerging energy
research that will have a long-term,
transformative effect on Hong Kong
and the nation’s energy future. The
Institute also promotes knowledge
transfer in collaboration with local and
international partners and establishes
a channel of communication between
the University and the public through
outreach activities.
HKUST Energy Institute:
Powering Forward
85˚C
Disaggregated
25˚C
Strongly
aggregated
PROF HENRY YAN
Assistant Professor of Chemistry
This is a really exciting
scientific development.
Our new organic solar cells
have the potential to reach
conventional inorganic
performance levels
ene materials for use in high-efficiency
polymer solar cells. In addition, he is
working together with Prof Ching W Tang
and physics colleagues, including Prof KS
Wong and Prof Jiannong Wang, to bet-
ter understand the properties of the new
synthesized materials and improve solar
cell performance. Other HKUST research-
ers are working on harvesting solar
energy through chemical means. Prof
Zhiyong Fan and his research team focus
on engineering nanostructured materials
with enhanced light absorbing characteris-
tics, while Prof Shihe Yang and his group
have developed methodologies for syn-
thesizing monodispersed nanostructured
materials of transitionmetals with specif-
ic properties to be used for solar cells.
