The new TFT, says the company, withstands a million bending cycles to a 1 mm radius of curvature and demonstrates advantages for practical application, such as an on/off current ratio of at least 107 with carrier mobility - which characterizes how easily an electron or hole can move through a metal or semiconductor - of 10 cm2/Vs or more. Flexible electronics are seen in foldable smartphones and their application is anticipated for wearable sensors, medical devices, smart packaging, and more.
"We have achieved unprecedented flexibility and durability by combining existing TFT technologies," says Manabu Ito, development manager at Toppan. "This breakthrough raises the potential for ultra-thin, unbreakable flexible sheet sensors and stretchable devices in the future."
While organic TFTs are lightweight and flexible, their disadvantages include low carrier mobility, reliability, and durability. On the other hand inorganic TFTs provide high carrier mobility and have an established mass production process, but their flexibility needs improvement. There is consequently demand for new TFTs combining outstanding carrier mobility, flexibility, and durability, says the company.
The company leveraged unique technologies and a new structure to create what it claims is the world's first TFT with:
- the flexibility to be wound around a mechanical pencil lead,
- the durability of a flexible printed circuit board,
- and carrier mobility exceeding 10 times that of amorphous silicon TFTs.
Flex testing shows no variation in carrier mobility and other properties before and after a million bending cycles to a 1 mm radius of curvature. The company says it aims to advance manufacturing technology, enhance flexibility, durability, and carrier mobility, and target the development of flexible sensors.