title: Air-stable flexible organic light-emitting diodes enabled by atomic layer deposition.
abstract: Organic light-emitting diodes (OLED) are an energy-efficient light source with many desirable attributes, besides being an important display of technology, but its practical application has been limited by its low air-stability. This study demonstrates air-stable flexible OLEDs by utilizing two atomic-layer-deposited (ALD) films: (1) a ZnO film as both a stable electron-injection layer (EIL) and as a gas barrier in plastics-based OLED devices, and (2) an Al2O3/ZnO (AZO) nano-laminated film for encapsulating the devices. Through analyses of the morphology and electrical/gas-permeation properties of the films, we determined that a low ALD temperature of 70 °C resulted in optimal EIL performance from the ZnO film and excellent gas-barrier properties [water vapor transmission rate (WVTR) <5 × 10(-4) g m(-2) day(-1)] from both the ZnO EIL and the AZO encapsulating film. The low-temperature ALD processes eliminated thermal damage to the OLED devices, which were severe when a 90 °C encapsulation process was used, while enabling them to achieve an air-storage lifetime of >10,000 h.
authors.affiliation: Department of Materials Science and Engineering, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei, Taiwan, People's Republic of China.
authors.forename: Yuan-Yu
authors.initials: YY
authors.lastname: Lin
authors.forename: Yi-Neng
authors.initials: YN
authors.lastname: Chang
authors.forename: Ming-Hung
authors.initials: MH
authors.lastname: Tseng
authors.forename: Ching-Chiun
authors.initials: CC
authors.lastname: Wang
authors.forename: Feng-Yu
authors.initials: FY
authors.lastname: Tsai