No abstract

Stretchable electronics are a promising technology for introducing new styles of display applications and for realizing displays that can be adapted to various free shapes, such as domes and spheres, to suit various viewing styles. To fabricate a stretchable display, it is necessary to form thin‐film transistors (TFTs) and light‐emitting devices on stretchable substrates. We demonstrate high‐performance stretchable metal oxide TFT islands on polyimide film using an acrylic adhesive structure. We developed mass transfer technology for metal oxide island TFTs on a polyimide film to be transferred on a stretchable substrate in a batch and a device structure with a passivation layer that stabilizes device characteristics when the substrate is stretched. The TFT showed stable switching characteristics with a mobility of 30 cm2/Vs without any fluctuation, even when the substrate was stretched from 0% to 50% and released to 0%.

Electrical leakage is one of the fatal faults associated with thin‐film devices (TFDs) including organic light‐emitting devices (OLEDs). To prevent electrical leakage, highly smooth electrodes are required to avoid the concentration of the electric field at local points. However, this requires the use of expensive electrode substrates. Here, OLEDs using inexpensive, aluminum‐foil‐based electrode substrates with an extremely high surface roughness are fabricated. A low leakage current is realized by incorporating extraordinary thick buffer layers of phosphotungstic acid (PWA) exhibiting the negative differential resistance (NDR) property. In its pristine state, PWA exhibits a high electrical resistance. However, upon applying electric current, the resistance is significantly decreased, resulting in increased conductivity and expression of NDR property, owing to the formation of conductive filaments and charge‐storage effects. The OLEDs produced with PWA achieve a low‐driving voltage and high external quantum efficiency simultaneously. Aluminum‐foil‐based OLEDs with a light‐emission area of 64 cm2 are fabricated. They emit steady luminescence even in crumpled and torn states. To the best of authors’ knowledge, this is the first report of a large‐area OLED exhibiting steady luminescence in such deformed states.