Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 92: Postersession DS/HL

HL 92.18: Poster

Donnerstag, 10. März 2016, 16:00–19:00, Poster A

Transparent white AC/DC OLEDs — •Felix Fries, Markus Fröbel, Simone Lenk, and Sebastian Reineke — Institut für Angewandte Photophysik, Technische Universität Dresden, Germany

Future lighting applications will strongly benefit from transparent luminescent devices. In this contribution, we demonstrate transparent organic light-emitting diodes (OLEDs), which allow for flexible adjustment of the emission color. We extend the AC/DC concept, that was only recently presented for bottom-OLEDs, to transparent devices. Since two units are stacked on each other and the cathode of one is connected to the anode of the other, they can be addressed independently via an AC-signal. Comprising blue and yellow emission units leads to the possibility to tune the color between deep blue over cold and warm white to yellow emission.

Based on optical simulation, we build OLEDs that show an overall transparency of 62% when switched off and emit warm white light to both sides (top, bottom) with an overall power efficacy of 11.8 lm/W at a brightness of 1000 cd/m² when switched on. Moreover, devices without indium-tin oxide (ITO) are presented, which exclusively rely on highly transparent ultra-thin metal electrodes. These ITO-free devices achieve a power efficacy of 18.4 lm/W at 1000 cd/m² for warm white emission and 56% transmission.

Using an emitter combination providing red, green, and blue emission, we were also able to achieve a high color-rendering index (CRI) of 84, which further expands the range of possible applications for this promising device concept.