QUT researchers have identified a new material that could serve as a flexible semiconductor in wearable devices by using a technique that manipulates the spaces between atoms in crystals.
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In a study published in the journal Nature Communications, the team applied “vacancy engineering” to enhance the performance of an AgCu(Te, Se, S) semiconductor—an alloy composed of silver, copper, tellurium, selenium, and sulfur—enabling it to convert body heat into electricity more effectively.
Vacancy engineering involves studying and adjusting the empty spaces, or "vacancies," in a crystal structure where atoms are missing. These vacancies can be used to improve a material's mechanical strength, electrical conductivity, or thermal performance.
The team is affiliated with the ARC Research Hub in Zero-emission Power Generation for Carbon Neutrality, the QUT School of Chemistry and Physics, and the QUT Centre for Materials Science.
The article outlines how the researchers, using advanced computational design, synthesised a flexible AgCu(Te, Se, S) semiconductor through a simple, cost-effective melting method. Mr Li explained that by precisely controlling atomic vacancies, they not only improved the material’s ability to convert heat into electricity but also enhanced its mechanical properties, making it adaptable for more complex applications.
To highlight its practical potential, the team designed several micro-flexible devices based on the material that could be easily attached to a person’s arm.
Mr Li said the study tackled the challenge of improving the heat-to-electricity conversion efficiency of AgCu(Te, Se, S) while maintaining the flexibility and stretchability required for wearable devices.
Thermoelectric materials have drawn widespread attention over the past few decades in light of their unique ability to convert heat into electricity without generating pollution, noise, and requiring moving parts. As a continuous heat source, the human body produces a certain temperature difference with the surroundings, and when we exercise, that generates more heat and a larger temperature difference between the human body and the environment.
Nanhai Li, Study First Author, Queensland University of Technology
Professor Chen noted that as flexible electronics continue to advance, the demand for flexible thermoelectric devices is rising, and QUT researchers are leading efforts in this space.
In a separate recent study published in Science, Professor Chen and colleagues from the ARC Research Hub developed an ultra-thin, flexible film capable of powering next-generation wearable devices using body heat—eliminating the need for batteries.
The key to advancing flexible thermoelectric technology is to examine wide-ranging possibilities. Mainstream flexible thermoelectric devices are currently fabricated using inorganic thin-film thermoelectric materials, organic th”ermoelectric materials deposited on flexible substrates, and hybrid composites of both.
Zhi-Gang Chen, Professor, Queensland University of Technology
“Both organic and inorganic materials have their limitations – organic materials typically suffer from low performance and while inorganic materials offer better conductivity of heat and electricity, typically they are brittle and not flexible. The type of semiconductor used in this research is a rare inorganic material that has striking potential for flexible thermoelectric performance. However, the underlying physics and chemistry mechanisms for enhancing its performance while maintaining exceptional plasticity remained largely unexplored until now,” Chen concluded.
Journal Reference:
Li, N.-H., et al. (2025) Strategic vacancy engineering advances record-high ductile AgCu(Te, Se, S) thermoelectrics. Nature Communications. doi.org/10.1038/s41467-025-58104-