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An improved efficiency from an encapsulated flexible top-emitting organic light-emitting device (FTOLED) has been demonstrated by integrating a microstructure onto the polymer encapsulation film. Soft-nanoimprint lithography is employed to integrate the microstructure onto the polymer surface, which enables large area fabrication with high quality, low cost, and repeatable use of the poly(dimethylsiloxane) mold. The light extraction of the FTOLEDs has been improved by integrating the microstructure with two-dimensional tapered micropillars array on the polymer encapsulation film, which can suppress the reflection by enhancing the critical angle of total reflection owing to its gradually changed refractive index. Moreover, the microstructured surface exhibits a hydrophobic property owing to its high contact angle, which results in a self-cleaning ability to protect the FTOLEDs from being polluted by water droplets and dust particles in practical applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] Viewing-angle independent WTOLEDs have been fabricated. [•] A microcavity with a periodically and gradually changed cavity length has been constructed. [•] The periodic microstructured cavity has been introduced into the WTOLEDs. [•] The viewing-angle independence in both the spectrum and CIE coordinates are obtained. [•] The microstructured WTOLEDs show comparable efficiency to that of the planar TOLEDs. [ABSTRACT FROM AUTHOR]

Abstract: Introduction of microstructures into an organic light-emitting device (OLED) is being considered as an effective approach to outcouple photons trapped in waveguide (WG) and surface plasmon-polariton (SPP) modes within the devices. However, the attempt has been hampered by the difficulty in applying lithographic patterning technologies on organic materials. Here, we show the end has been simply reached by one-step directly laser ablating the hole-transporting layer of the OLEDs without inducing any optical or electrical deterioration. Three times efficiency enhancement has been experimentally attained from the corrugated OLEDs, which has then been ascribed by numerical simulation to the efficient outcoupling of the SPP and WG modes to radiation. [Copyright &y& Elsevier]