Ultraviolet-Sensitive OLED with Tunable Wavelength and Intensity by Integrated ZnO Nanowires Schottky Junction

Organic light-emitting diode (OLED) displays are one of the dominant flat panel display technologies. Here, a novel ultraviolet (UV)-sensitive OLED (USO) is reported, which emits visible light with adjustable wavelength and brightness according to the intensity of the incident UV light. The USO employs zinc oxide nanowires (ZnO NWs) with Schottky junctions to control current and engages exciplex-emitting OLED to emit light according to the incident UV light. As the UV light intensity increases from 0.09 to 8.15 mW cm⁻², USO emits light with a peak wavelength that ranges from 595 to 525 nm, a color coordinate from (0.458, 0.485) to (0.339, 0.555), and a light intensity that is anywhere from 97 to 6915 cd m⁻². The USO has a fast photoresponse characteristic due to the effect of the Schottky barrier introduced by the close contact of the ZnO NWs and gold electrodes. The luminescence color of the USO changes from dark orange to harsh green because of the exciplexes’ different formation ratios under differing UV intensities. As a result of the USO taking advantage of the Schottky barrier and exciplex, the realization of many innovative applications in optoelectronic devices is possible.