Highly Efficient and Reliable Organic Light-Emitting Diodes Enabled by a Multifunctional Hazy Substrate for Extreme Environments

As transparent, flexible, and wearable organic electronics degrade under normal outdoor environmental conditions (e.g., water vapor, oxygen, and UV light) and extreme environments, including washing or rain, a customized encapsulation technology is required to improve device reliability. Herein, a simple process is presented for fabricating multifunctional hazy substrates (MFHSs) with excellent gas diffusion barrier (GDB), flexibility, UV reflectance, light scattering, and waterproof properties. First, a spiky polyethylene terephthalate (PET) surface is produced with 76.0% optical haze through ion-beam treatment followed by the formation of a hydrophobic layer to achieve a waterproof effect (contact angle: 153.3 degrees). Then, a multifunctional multibarrier film is fabricated based on a nano-laminated distributed Bragg reflector and functional polymer on the functional PET substrate to serve as a GDB and UV filter. This multibarrier film has excellent mechanical and chemical stabilities, in addition to having a water vapor transmission rate of 10(-6) g m(-2) day(-1) and UV transmittance of <3%. The so-fabricated MFHS not only increases the device efficiency by 73% but also enables a highly flexible and environmentally stable organic light-emitting diode. The surface treatment and encapsulation technologies developed in this study are expected to increase the lifetime of organic devices and facilitate high outdoor usability.