A team of researchers has successfully created thin-film transistors through liquid processing that perform well even at low temperatures. This breakthrough opens doors for their use in advanced flexible electronics and wearable devices, as they can function on plastic substrates and reliably perform when subjected to repeated bending.
DGIST (under the leadership of President Kunwoo Lee) has announced that a research team headed by Professor Kwon Hyuk-joon from the Department of Electrical Engineering and Computer Science, assisted by first author Dr. Jang Bong-ho, has innovated a method to fabricate high-performance electronic components using liquid processing at lower temperatures than before. By utilizing the “heat of combustion” generated in the materials, this technology eliminates the need for high temperatures, making it suitable for heat-sensitive plastic substrates. This advancement is expected to find extensive application in bendable and foldable electronic devices as well as smart wearable technology.
Nowadays, flexible and lightweight electronic devices are becoming increasingly common. Gadgets like smartwatches, foldable displays, and wearable sensors provide added convenience and versatility, promising to reach various industry sectors in the coming years. To manufacture these innovative products, strong yet flexible electronic parts are crucial.
Thin-film transistors are vital for developing flexible electronics, requiring them to be extremely thin and precisely made. Generally, liquid-phase processing, which applies coatings in liquid form, is ideal for economical mass production. However, the high temperatures needed for high-quality thin film production have limited their use on flexible heat-sensitive plastic substrates. Thus, researchers have been working on new methods to decrease the required temperatures while still achieving excellent performance.
To address these challenges, Professor Kwon’s team employed a “combustion synthesis” technique. Similar to how a heat pack generates internal heat to warm up, this method utilizes the heat produced within the material during processing to create high-quality oxide films without elevating the external temperature. Using this approach, the team successfully produced a high-performance thin-film transistor on a plastic substrate at just 250 degrees Celsius.
The resulting transistor exceeds existing models in flexibility and durability. It retains outstanding electrical performance even on thin, bendable plastic substrates and has shown stable functionality after more than 5,000 bending cycles. This makes it an excellent candidate for next-generation flexible electronics and wearable gadgets.
“Traditional liquid-phase materials boast significant advantages in their compatibility with printing techniques. However, they also face challenges, including the high temperatures needed to form quality thin films, which complicates their application on flexible, low-thermal-resistance substrates,” explained Prof. Kwon from the Department of Electrical Engineering and Computer Science. “The findings from this study dramatically lower the processing temperatures of high-performance liquid-phase materials, enabling broader application possibilities across various sectors.”
Dr. Jang Bong-ho is the first author of this study, with Prof. Kwon as the corresponding author. Their research has been published online in the journal npj Flexible Electronics and received support from the Ministry of Science and ICT’s Future Convergence Technology Pioneer STEAM Research Program and Nanomaterial Technology Development Program.
