Flexible semiconductor is thermoelectric generator
Researchers in Australia have identified a new material which could be used as a flexible semiconductor in wearable devices to generate power from thermal energy.
The team at the Queensland University of Technology used a technique that focuses on the manipulation of spaces between atoms in crystals with an AgCu(Te, Se, S) semiconductor. This is an alloy made up of silver, copper, tellurium, selenium and sulphur,
Vacancy engineering in a crystal can improve its mechanical properties or optimising its electrical conductivity, or thermal properties.
The team synthesised a flexible AgCu(Te, Se, S) semiconductor through a simple and cost-effective melting method with precise control of the material’s atomic vacancies.
To demonstrate the practical application potential of the material, the researchers designed several different micro-flexible devices based on the material that could be easily attached to a person’s arm.
“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,” said researcher Nanhai Li.
“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.”
The ductile p-type (AgCu)0.998Te0.8Se0.1S0.1 was combined with n-type commercial Bi2Te3 and achieves a power density of ~126 μW cm−2 under a 25 degree temperature difference, demonstrating significant application prospects for wearable electronics.
“The key to advancing flexible thermoelectric technology is to examine wide-ranging possibilities,” said Prof Zhi-Gang Chen who led the research.
“Mainstream flexible thermoelectric devices are currently fabricated using inorganic thin-film thermoelectric materials, organic thermoelectric materials deposited on flexible substrates, and hybrid composites of both.
“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,” he said.
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