QUT researchers advance flexible semiconductor technology

Vacancy engineering involves controlling the empty spaces where atoms are absent in a crystal lattice. This approach can influence key material properties, such as electrical conductivity, thermal performance, and mechanical flexibility. By applying this method, the QUT team enhanced the material’s ability to convert body heat into electricity, while also improving its flexibility—an essential characteristic for wearable technology.

The research team, led by first author Nanhai Li, included contributors from 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. Guided by advanced computational modelling, the team synthesised the semiconductor using a straightforward and cost-effective melting process.

Mr Li explained that controlling atomic vacancies not only boosted the material's thermoelectric efficiency but also provided it with adaptable mechanical properties, allowing it to be shaped for complex, real-world applications. To illustrate its potential, the researchers developed several micro-flexible devices based on the material, designed to be worn on the arm.

The study addressed a key challenge in thermoelectric materials research: enhancing the conversion of heat to electricity while ensuring the material remains flexible and stretchable—qualities critical for wearable devices. Mr Li noted that thermoelectric materials had attracted significant attention due to their ability to generate electricity from heat without producing pollution, noise, or requiring moving parts.

With the human body offering a constant heat source, particularly during physical activity when temperature differences with the environment increase, such materials could provide a sustainable power solution for wearable electronics.

Professor Zhi-Gang Chen highlighted the growing demand for flexible thermoelectric devices alongside the rapid development of flexible electronics. He positioned QUT researchers at the forefront of efforts to meet this demand.

In related work, published separately in Science, Professor Chen and colleagues developed an ultra-thin, flexible film capable of powering wearable devices using body heat, removing the need for conventional batteries.

Professor Chen emphasised the importance of exploring diverse approaches to advance flexible thermoelectric technology. He noted that while current devices typically rely on inorganic thin films, organic materials, or hybrid composites, each option presents limitations. Organic materials often deliver lower performance, whereas inorganic materials, despite superior conductivity, tend to be brittle.

The AgCu(Te, Se, S) semiconductor represents a rare inorganic material offering both flexibility and strong thermoelectric performance. Until now, the mechanisms behind enhancing its efficiency while retaining plasticity had remained largely unexplored. The QUT team’s research provides new insight into these mechanisms, marking a step forward in the development of next-generation wearable energy solutions.