Excitonic Light Management (Platform 1.1)

What’s this platform about?

The goal of this platform is to tame the solar spectrum, by controlling the energy and spatial dimension of light. By doing this we aim to exceed the 34% Shockley-Queisser efficiency limit for light-to-electricity energy conversion.

Photochemical upconversion is the process of converting two low-energy photons into one of higher energy. Designing materials which can exploit this process would allow us to utilise energy from the infrared part of the sun’s spectrum and transform it into higher energy so it can be converted into electric current.

Luminescent solar concentration is a process whereby the energy density of light hitting a surface can be increased by concentrating the light absorbed over a large area into a much smaller area via waveguiding. A Luminescent Solar Concentrator (LSC) can improve the efficiency of upconversion and also allow solar energy collection to be integrated into building architecture.

Research Highlights

Collaborations

Industry: The Mulvaney and Ghiggino groups are still working with ClearVue PV on solar windows. A postdoc with industry experience, Qingrui Kong, was hired in 2023 to work on quantum dot-polymer integration in films in close collaboration with ClearVue PV. A connection has been established with Melbourne Safety Glass to investigate local manufacturing options for solar windows..

Outlook for next year

Our priority is to achieve efficient solid-state upconversion devices and to achieve a dye/quantum dot-based LSC with performance exceeding published benchmarks.

Beyond this, we aim to design guidelines and develop understanding of the physical chemical aspects of upconversion systems to allow the development of efficient solid-state upconversion devices and to demonstrate an improved LSC dye/nanocrystal formulation that offers commercial potential.

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Solution-Processed Next Generation Photovoltaics (Platform 1.2)

What’s this platform about?

Platform 1.2 aims to investigate emerging materials within solar cell architectures that can go beyond traditional silicon in efficiency or utility.

This is being achieved by developing new materials and device architectures through advanced theoretical and synthetic combinatorial screening approaches, advanced device simulation and characterisation methods.

We are developing microstructurally controlled solar cell absorbers on graphene electrodes and microstructurally controlled, lead-free and NIR thin films.

We are attempting to quantitatively describe the operation of a solar cell based on a new material or optoelectronic phenomenon and are seeking to experimentally validate the predictions of a simulated solar cell device based on simulated material properties.

We are continuing to advance perovskite materials and their solar cells and develop lead-free solar cell materials. We are working on semi-flexible silicon solar cells for use in alternative photovoltaic applications.

Progress in 2023

The Melbourne Centre of Nanofabrication commissioned a unique combinatorial sputtering system with in-situ characterization to accelerate materials development, alongside tools to assess solar cell performance under UV and thermal cycling. Their high-throughput energy materials discovery platform completed factory acceptance testing in November 2023 and was shipped to Australia in December 2023.

In 2022, Exciton Science supported the commercialization of a new conductive coating technology, leading to further funding in 2023 from the Office of National Intelligence and Australia’s Economic Accelerator, and the spin-out of Green Shield Solutions.

A theoretical framework was developed for identifying promising photovoltaic absorber materials, focusing on perovskite-like materials, and identifying six candidates from over 129,000 for further exploration and optimization via in-silico simulations.

Two force fields for simulating perovskite formation, including direct nucleation from solution and two-step processing, have been developed to understand the effects of processing conditions and additives on perovskite formation.

Simulations were used to understand the thermodynamic forces affecting metal halide perovskite formation and stability, including the roles of light and heat in mixed-halide perovskites and the effectiveness of MACl in wide bandgap perovskite solar cells.

Functionalized, imidazolium-based phosphonic acids were developed for interfacial passivation in perovskite solar cells, showing modest work-function shifts but no major efficiency improvements when used as SnO2 electron transport replacements.

Research on novel hole transport layers led to the development of strontium-modified NiO nanoparticles, creating a hierarchical hole-transporting layer for perovskite solar cells, improving efficiency to over 20% and stability to over 95% after 1000 hours.

Lead acetate was identified as a promising precursor for methylammonium lead halide perovskite solar cells, offering more efficient and stable cells than the lead iodide route, with a novel synthesis route developed for formamidinium caesium lead halide perovskites.

Collaboration with Prof. Henry Snaith’s group at Oxford University led to the discovery that adding dimethylammonium salts to perovskite precursor-solution forms intermediate phases, improving film orientation, performance, and stability through subsequent thermal annealing.

Research on CZTS as an alternative solar cell material to silicon continued, with a focus on its cost-effectiveness and abundance, achieving an 11.1% efficiency milestone in collaboration with a solar cell project.

Research on perovskite solar cells for X-ray detection demonstrated their high efficiency in detecting both soft and hard X-rays, leading to the development of fully flexible and scalable all-printed devices.

Flexible silicon solar cell modules, developed in partnership with Woodside Energy, focused on module design optimization and environment testing, leading to a provisional patent submission for the work.

Research Highlights

Risk/mitigation

Major staff changes following COVID-19 have induced reshaping of key research groups aligned to this platform. As such, progress has slowed as recovery of group cohorts is initiated.

Collaborations

Industry - Dr Noel Duffy (CSIRO), Mitsuru Imaiizumi (JAXA), Chris Ryan (CSIRO), Jitendra Joshi (Woodside Energy, Boon Siaw (Woodside Energy)

International - Obadiah Reid (NREL), Federico Pulvirenti, Stephen Barlow, Seth R. Marder (Georgia Institute of Technology & University of Colorado Boulder, USA), Jian Wang, Yangwei Shi, David Ginger (University of Washington, USA), Sandheep Ravishankar (Forschungszentrum Jülich), Takeshi Ohshima (QST), Dr Ben Diroll (Argonne National Lab), Laura Herz and Henry Snaith (Oxford).

Outlook for next year

In 2024, we will complete several perovskite formation studies, focusing on two-step formation, precursor thermodynamics, and crystal growth mechanisms. Research on chiral perovskites and nanocrystals has begun.

We're also exploring non-lead solar cell materials, particularly complex metal oxides and binary metal antimonides, using various deposition methods.

Our solar windows project will advance semi-opaque perovskite solar cells. These devices, already showing promising colour-neutrality and performance, will be developed using solution processing and molecular imprinting to achieve over 30% transparency and over 15% efficiency.

For the CZTS Work Package, we aim to scale up the optimal solar cell design and discuss commercialization with partners like Wuhan Institute of Technology and Prof Yibing Cheng. Chang-Qi Ma from Suzhou, a key partner, is interested in prototype development at their Suzhou printing centre.

Finally, our semi-flexible silicon project will progress with tailored architectures for module development, focusing on scalability, electrical, mechanical, and environmental stability, aiming for a spin-out in Q2 2024.