Researchers in Bengaluru have developed an innovative thin-film material that could significantly improve the sensitivity of temperature and heat-sensing devices. Made from scandium nitride, the material produces an unusually strong electrical response when exposed to temperature differences, opening up potential applications in thermal imaging, heat-flow monitoring and waste-heat recovery.
Scientists at the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) found that the material can generate more than 124 millivolts of voltage for every one-degree Kelvin difference in temperature under specific conditions near room temperature.
The response is nearly 100 times higher than what conventional theories would predict for ordinary solid materials. The findings, published in the journal Science, could eventually contribute to the development of highly sensitive thermal sensors and technologies designed to convert excess heat into useful electricity.
JNCASR Team Makes Breakthrough in Thin-Film Technology
The research was led by Renuka Karanje and Dheemahi Rao, under the guidance of Bivas Saha. Diksha Dadhich and Sourav Rudra from JNCASR also contributed to the study, along with researchers from the University of Sydney and the Indian Institute of Science (IISc).
The research team has also submitted an Indian patent application covering the thin-film materials and sensor technologies developed during the work.
The discovery is based on the Seebeck effect, a phenomenon in which a temperature difference across a material generates an electrical voltage.
Normally, conventional thermoelectric materials produce relatively small signals of around 100 to 500 microvolts per Kelvin. The JNCASR researchers, however, found a way to dramatically increase the response by changing how electrical charges move through scandium nitride.
How Does the New Material Work?
To achieve the enhanced response, the scientists introduced magnesium into scandium nitride while retaining a high concentration of charged impurities within the material.
This modification changes the electrical structure of the thin film. Charges become concentrated in small conducting regions separated by barriers.
When the temperature changes, electrical charges move between these regions. This unusual movement produces a much larger voltage than would normally be expected from the material.
The result is a thin film with exceptionally high thermoelectric sensitivity.
Thin Films Show Strong Temperature Response
During experiments, researchers tested a film approximately 200 nanometres thick.
At around 350 Kelvin, or 77°C, the film generated a response of approximately -124.6 millivolts per Kelvin.
The researchers also discovered that film thickness plays an important role in the strength of the effect.
A much thinner film, measuring just 7.5 nanometres, produced a response of approximately -83.41 millivolts per Kelvin at temperatures close to room temperature.
These results demonstrate the potential of engineered scandium nitride thin films for creating highly responsive thermal sensing technologies.
Potential Applications in Thermal Imaging and Heat Recovery
The unusually strong electrical response could have several practical applications.
One potential use is the development of high-sensitivity temperature sensors capable of detecting very small changes in temperature.
The technology could also be useful for advanced thermal imaging systems, where detecting subtle temperature differences is essential.
Another promising area is heat-flow measurement. More sensitive sensors could allow engineers and researchers to monitor thermal energy with greater precision.
The technology may also have implications for thermoelectric energy harvesting. Devices based on similar principles could potentially capture some of the heat that is normally wasted and convert it into electrical energy.
A Promising Step for Next-Generation Heat Sensors
The Bengaluru researchers’ work demonstrates how carefully engineering the electrical properties of thin films can produce dramatically different thermoelectric behaviour.
Although further research and development will be needed before the technology can be incorporated into commercial devices, the results provide a promising foundation for next-generation heat sensors, thermal imaging systems and waste-heat energy technologies.
The discovery could ultimately help scientists develop smaller and more sensitive devices capable of detecting temperature changes that conventional materials struggle to measure.