Leaving Lead Behind

• Applicant: Ryan Crisp, Ph.D.
• Subject Area: Solid State and Surface Chemistry, Material Synthesis ; Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 542141531

While renewable sources are increasingly replacing fossil fuels in the production of electrical energy, their widespread use requires further advancement in terms of material properties and processing costs to achieve the EU goal of a low-carbon economy by 2050. Improving the efficiency of solar energy conversion into electricity with less expensive materials and easier methods is a game changer in renewable energy research. Great progress has been made in this direction developing a remarkable material called perovskite. However, one significant barrier limiting the full adoption of perovskite technology is the component heavy metal lead (Pb) which is a banned substance for commercial products in the EU. A second barrier is the instability of the material when exposed to moisture. Research must focus on finding alternatives to Pb-based material. One alternative perovskite material theorized to achieve high performance is the low-toxicity, earth-abundant barium zirconium trisulfide (BaZrS3). However, controlled synthetic methods of BaZrS3 perovskite lag far behind Pb-based ones – a gap this project overcomes by developing methods for its fabrication, assessment of material properties, and prototyping devices. Here my expertise on both inorganic synthesis and solid-state physics represents the ideal combination to achieve groundbreaking results on a stable, promising material for solar cells, photoelectrochemical devices, and as light emitters. This proposal exploits the large synthesis parameter-space developed for similar chalcogenide materials to make perovskites based on barium, zirconium, and sulfur which are all abundant and not critical elements. The work packages (WPs) of this project are: (WP1) investigation into atomic layer deposition of BaZrS3 thin films, (WP2) methodology for BaZrS3 perovskite nanocrystal synthesis through colloidal hot-injection and heat-up techniques, (WP3) characterization of material properties (i.e., crystal structure & size, light absorbance, luminescence, carrier mobility, bandgap tunability through alloying and quantum confinement) and (WP4) to assemble prototypical devices (solar cells, transistors, photoelectrochemical cells). Achieving results on the WPs provides novel synthetic routes and sets up future research expanding upon this powerful technology. There is ample opportunity for interdisciplinary exchange: a combination of expertise in organic and inorganic chemistry, chemical engineering, physics, and spectroscopy taken to design precursors and ligands, measure and calculate electronic structure, and characterize the optoelectronics. This holistic approach provides an ideal framework in creating new materials for energy applications. “Leaving Lead Behind” searches for a perfect material with high luminescence, good charge carrier transport, a tunable and suitable bandgap, that is stable and marketable. The proposed project researching BaZrS3 provides the answer to that search.

• DFG Programme: Research Grants