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Reproducible synthesis of nanocrystals with tunable properties for sustainable energy solutions

Periodic Reporting for period 1 - NANO-TUNE (Reproducible synthesis of nanocrystals with tunable properties for sustainable energy solutions)

Reporting period: 2019-04-01 to 2021-03-31

To meet growing energy demands, sustainable energy solutions require new materials with tunable properties. For example, different materials can absorb different wavelengths of light that can then be converted to energy using solar cells. By using many materials together in a solar cell, a larger portion of light that hits the earth’s surface can be converted to energy. The properties of nanomaterials can be tuned with size, and therefore enable a library of tunable materials to be created using the same parent material. The properties of materials can also be tuned by changes in their composition. Copper sulfide is a unique material because the copper in copper sulfide can readily undergo exchange with a variety of metals to make new compositions, containing three or four elements, that have different properties. By using copper sulfide nanoparticles, we have two different ways to change the material properties, nanoparticle size and nanoparticle composition. However, the ability to finely tune nanoparticle size and composition is still a challenge which requires more research. In NANO-TUNE we used advanced X-ray techniques (mainly Pair Distribution Function Analysis of X-ray total scattering data (PDF)) to study the formation of copper sulfide nanoparticles and to study cation exchange of copper sulfide nanoparticles to different compositions. The objective was to make nanoparticles more reproducibly with increased tunability of their material properties. NANO-TUNE was carried out at the University of Copenhagen and hosted by Professor Kirsten Jensen, a leader in field of PDF.
The work carried out for NANO-TUNE during the period from 1/4/2019 to 31/3/2021 was in line with the proposed work with minor deviations. NANO-TUNE resulted in the investigation of the nanoscale structure of copper sulfide nanoparticles and relation of that structure to their optical properties. Cation exchange of copper sulfide nanoparticles with both indium and tin has been studied and the synthetic parameters which lead to different degrees of cation exchange determined. A new apparatus to study nanoparticle reactions while they are occurring was developed and preliminary X-ray scattering data of the formation of copper sulfide nanoparticles has also been collected. Training resulted in gained scientific and transferrable skills, including nanomaterial synthesis, material structural analysis, project management, leadership, writing, communication and entrepreneurship. Three publications are in progress from this work. In addition, a review on the PDF method for a synthetic nanocrystal audience has been published and there are 4 publications that are expected from collaborations that took place during NANO-TUNE. Three talks and two posters were presented to scientific audiences during the project and three talks to the general public. Deliverables, including multiple publications to high impact journals, are delayed because of the Covid-19 pandemic, which made beamtime for X-ray experiments more competitive due to beamtime cancellations and travel restrictions in 2020 and 2021.
NANO-TUNE has resulted in a deeper understanding of the formation of copper sulfide nanoparticles and their cation exchange to copper indium sulfide and copper tin sulfide. Collaborations during NANO-TUNE have also helped international labs use the advanced X-ray techniques we use in the Nanostructure group to study the formation and structure of other nanoparticle materials. The work done with NANO-TUNE contributes to the foundation of work required before copper sulfide nanoparticles and their derivatives can be used commercially in solar applications.
NANO-TUNE: Cation exchange of nanoparticles to harness solar energy