Researchers have experimentally shown that chalcogenide perovskites can emit light more efficiently than previous measurements suggested, strengthening the case for investigating the materials for future solar cells, photodetectors, and other optoelectronic devices.
The team, led by Mirjana Dimitrievska at Switzerland’s Empa research institute, worked with researchers from the Helmholtz-Zentrum Berlin für Materialien und Energie and other partners. Their study examined barium zirconium sulfide, a chalcogenide perovskite whose light-emission properties Empa said researchers had not previously demonstrated experimentally.
The results also revealed a challenge. Although single crystals showed relatively strong light emission, defects introduced during synthesis and processing significantly suppressed the same property in thin films.
Measuring light output
Perovskites are defined by their crystal structure rather than one particular chemical composition. While halide perovskites have received considerable attention for solar cells, chalcogenide perovskites are being investigated as alternatives because they combine potentially useful optical and electronic properties with greater material stability and constituent elements that are abundant in Earth’s crust.
The challenge has been establishing whether their predicted properties translate into measurable performance. Until now, Empa reports that the light-emission efficiency of chalcogenide perovskites has not been experimentally demonstrated.
To investigate the material, the researchers used advanced spectroscopic techniques to measure photoluminescence in a barium zirconium sulfide crystal produced at the Helmholtz-Zentrum Berlin. Photoluminescence occurs when a material absorbs energy and subsequently emits light. The findings were published in Advanced Optical Materials.
The measurements showed relatively strong emission from the single crystal, consistent with theoretical predictions. Thin films, however, exhibited substantially weaker photoluminescence. This difference matters because promising materials must eventually be synthesized and processed into practical device structures.
Defects introduced during those steps can disrupt the electronic processes needed for efficient light emission, potentially limiting a material’s performance even when its underlying crystal structure is favorable. The researchers’ findings therefore provide both a positive result and a development challenge: the material’s intrinsic potential appears promising, but manufacturing processes will need further refinement.
Potential beyond solar power
Researchers are investigating chalcogenide perovskites for applications including solar cells and photodetectors. Their stability and constituent elements could make them attractive candidates for optoelectronic technologies, although the research remains at an early stage.
The new measurements help researchers distinguish between limitations inherent to a material and those caused by synthesis or processing. Spectroscopic analysis can reveal whether poor performance stems from defects in the material itself or from other issues in a prototype device, helping guide subsequent improvements.
Empa emphasized that considerable development remains before chalcogenide perovskites are ready for practical applications. The results show promising light emission in single crystals, not a commercially viable solar cell or a proven improvement in solar-conversion efficiency.
Unexpected structures attract attention
The researchers are also investigating a second development emerging from the synthesis process. When chalcogenide perovskites are produced from their constituent elements, tiny needle-like structures with hexagonal cross-sections can form alongside the desired crystalline material.
Previously considered an undesirable byproduct, these structures have displayed unusual optical properties, including the ability to polarize, refract, and conduct light in distinctive ways. They may also have potential as superconductors and quantum materials.
With support from the Swiss National Science Foundation through its international Weave program, Dimitrievska’s team is collaborating with Friedrich-Alexander University Erlangen-Nürnberg in Germany to investigate these structures, improve their synthesis, and better understand their properties.
The researchers ultimately aim to integrate the needle-like materials into initial photonic and electronic components. Together, the two research directions show how a deeper understanding of material behavior can open new possibilities in optoelectronics.
Chalcogenide perovskites still face substantial engineering challenges, but experimentally confirming their light-emission properties provides a stronger foundation for deciding where further development may be worthwhile.