Page 19 - Spring 2025 Electron

Industry News Industry News

BREAKTHROUGH IN BREAKTHROUGH IN

MULTIFUNCTIONAL SOLAR LOW-COST HYDROGEN

CELL TECHNOLOGY PRODUCTION FROM SOLAR

Researchers at Oulu University have made multifunctionality in future photonic, computing, Researchers from Imperial College London properties, such as the light they absorb and their
a significant advancement in the field of sensing and energy harvesting devices. and Queen Mary University of London have electrical properties, which means they can be an
multifunctional energy harvesting by utilising revealed a new method of harnessing sunlight to extremely versatile platform on which to build various
Yang Bai, from Oulu University’s Microelectronics
the photovoltaic effect in ferroelectric crystals. In produce hydrogen. It demonstrates how organic ways to convert sunlight into fuels such as hydrogen,
Research Unit, who led the study, states:
particular the team looked to improve the electrical photoactive materials can be adapted to deliver or even chemicals, emulating natural photosynthesis
output from the bulk photovoltaic effect, or BPVE, “ The first concrete applications will be in small- high efficiency and long-term stability in solar in plants. This opens exciting new avenues for
via the manipulation of ferroelectric domains in scale sensing and computing devices, where water splitting. sustainable fuels and chemical production. “
oxide perovskite crystals. in addition to the electric signals we can input
The key challenge was the instability of organic Dr. Salvador Eslava, Lead Academic of the study
light of different wavelengths as an extra degree
In ordinary solar cells the method of harvesting materials such as polymers when exposed to water at Imperial College’s Department of Chemical
of freedom for operation. For example, we have
solar energy and converting it into green electricity and the inefficiencies introduced by energy losses Engineering, adds:
previously proven the use of BPVE in filterless colour
is based in the formation of p-n junctions in at critical interfaces. In order to address this the
sensors. Other examples include components “ This result is a significant improvement in organic
semiconductors. By comparison the BPVE does not team devised a multi-layer device architecture
for neuromorphic computing and multi-source photoelectrochemical device performance,
rely on p-n junctions to work under solar energy. incorporating a protective organic photoactive layer
energy harvesters for IoT devices. achieving record solar-to-hydrogen efficiencies.
Instead, it forms its own ‘self-junction’ enabling it to, and a graphite sheet functionalised with a nickel-iron
The approach leverages the advantages of organic
at least theoretically, break the physical limit of what While we are advancing in the working mechanism catalyst. By preventing water-induced degradation
bulk heterojunctions, which offer impressive
is known as the Shockley-Queisser limit that restricts inside the materials, the challenge still lies in the high photocurrent densities and device durability
photocurrents, photovoltages, abundant elements
the efficiency of single p-n junction-based solar cells. band gap of the materials, where we ideally need were achieved.
and ease of processing, and applies them to the
a material that simultaneously has a narrow band
Currently the output power of BPVE-based cells By combining a bulk heterojunction photoactive layer electrodes of photoelectrochemical cells. “
gap to maximise visible light absorption and a
is negligible relative to that of conventional p-n with the protective graphite sheet a photocurrent
large spontaneous polarisation to maximise the Reference: ‘UK Researchers unveil Breakthrough in producing Low-
junction-based photovoltaic cells, but by creating density of over 25mA per one hundredth of a cost Hydrogen from Solar’, Electrical Review, 18th. March
open-circuit voltage. We have limited options for
a ‘stacked domain structure’, a 35 per cent centimetre at +1.23V was achieved. Operational
such materials. Most available materials nowadays
improvement in the output power of these BPVE stability was also observed, supporting the possibility
only possess either a narrow band gap or a large
cells can be realised. A domain is a submicron- of real-world applications. Full water splitting was
spontaneous polarisation, not both. In the near
sized region containing spontaneous polarisations thus achieved generating hydrogen directly from
future we will attempt to expand the material
orienting in the same direction, which can be water and sunlight without the need for external
options. “
switched by applying an external electric field. electricity, and a solar-to-hydrogen of 5 per cent was
Reference: Bai, Y. et al, ‘Study on Influence of AC Poling on Bulk recorded.
The improvement in electrical output is achieved by Photovoltaic Effect in Pb(Mg1/3 Nb2/3) O3-PbTiO3 Single Crystals’,
applying an AC poling electric field, under which the Journal of Advanced Materials. Dr. Flurin Eisner, Lecturer in Green Energy at Queen
microstructure, i.e. the domains, inside the crystals Mary University of London, who led the development
become better aligned than under the present DC of the organic photoactive layers, comments:
field. On removal of the electric field, the domains
“ Our work demonstrates that high-performance,
remain in their better aligned state. These better
stable solar water splitting can be achieved using
aligned domains help to reduce the recombination
low-cost, scalable organic materials.
of electric charge carriers, so improving energy
conversion efficiency. As a result more efficient
BPVE cells are envisaged that can help unlock
Organic materials are highly tunable in terms of their
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