Viewing-angle independence of white emission from microcavity top-emitting organic light-emitting devices with periodically and gradually changed cavity length.

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]