Truly Wearable OLEDs with Moisture Impermeable and Flexible Textile Substrate Based on Mechanical Analysis of Textile Directionality: Toward Real Cloth-Type Display

Textile-based OLEDs (textile OLEDs) are emerging as free-form electronics capable of showing their versatile performance without temporal or spatial limitations. They can improve user convenience and human quality of life in the form of daily clothes for various uses: real-time information transfer, fashion, biomedical, and daily health-care applications. The most important challenge to realizing textile OLEDs is developing a multifunctional textile substrate that possesses cloth-like flexibility and softness, moisture impermeability to protect the sensitive OLED, and flatness for stable OLED growth. In this work, a soft as cloth, flat on the angstrom scale (Å), and moisture impermeable textile substrate was developed by introducing functional thin-film combination with inorganic and organic layers that prevents moisture and oxygen penetration. In addition, in-depth mechanical analyses of textile substrates were conducted according to the direction of the woven structure with account for the asymmetry of the general textile structure. Consequently, a mechanical analysis of textile directionality was primally presented, and based on this analysis, environmentally reliable and flexible three-colored (red, green, and blue) OLEDs were realized.