Three-Dimensional Connective Architecture-Based Integrated Organic Light-Emitting Diodes and Transistors on Fiber for...

Fiber-based organic light-emitting diode (OLED) displays have drawn increasing attention due to their inherent wearability and the superior performance characteristic of OLED technology. However, thin-film transistor (TFT)-based circuit-level integration on cylindrical fiber substrates has remained challenging due to their long and three-dimensional geometry, which limits the implementation of multiterminal configurations and x-y matrix structures. Here, the fiber-based three-dimensional (3D) integrated OLED-TFT with TFT-driven circuitry, enabled by a three-dimensional connective architecture (3DCA), is reported. The 3DCA fully exploits the cylindrical surface of the fiber by spatially separating active devices and signal terminals onto the upper and lower surfaces, respectively. Lateral conduction paths are formed through a simple tilting step during fabrication, enabling vertical electrical interconnection without additional processing and compensating for deposition shadowing on the sidewalls. As a result, the fiber OLED display operates with circuit-driven control while maintaining low gate leakage current (∼10^-10 A). Furthermore, the 3DCA allows full encapsulation through 3D coverage encapsulation strategies, ensuring stable operation even under water. This architecture not only achieves high performance but also establishes a TFT-based circuit beyond the device level, marking a paradigm shift toward fully operational fiber displays.