Universität zu Köln

Hillebrandt, Sabina ORCID: 0000-0002-2628-385X, Moon, Chang-Ki ORCID: 0000-0001-8286-5187, Taal, Adriaan J., Overhauser, Henry, Shepard, Kenneth L. and Gather, Malte C. ORCID: 0000-0002-4857-5562 (2023). High-Density Integration of Ultrabright OLEDs on a Miniaturized Needle-Shaped CMOS Backplane. Advanced Materials. p. 2300578. Wiley. ISSN 1521-4095

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Abstract

Direct deposition of organic light-emitting diodes (OLEDs) on silicon-based complementary metal–oxide–semiconductor (CMOS) chips has enabled self-emissive microdisplays with high resolution and fill-factor. Emerging applications of OLEDs in augmented and virtual reality (AR/VR) displays and in biomedical applications, e.g., as brain implants for cell-specific light delivery in optogenetics, require light intensities orders of magnitude above those found in traditional displays. Further requirements often include a microscopic device footprint, a specific shape and ultrastable passivation, e.g., to ensure biocompatibility and minimal invasiveness of OLED-based implants. In this work, up to 1024 ultrabright, microscopic OLEDs are deposited directly on needle-shaped CMOS chips. Transmission electron microscopy and energy-dispersive X-ray spectroscopy are performed on the foundry-provided aluminum contact pads of the CMOS chips to guide a systematic optimization of the contacts. Plasma treatment and implementation of silver interlayers lead to ohmic contact conditions and thus facilitate direct vacuum deposition of orange- and blue-emitting OLED stacks leading to micrometer-sized pixels on the chips. The electronics in each needle allow each pixel to switch individually. The OLED pixels generate a mean optical power density of 0.25 mW mm−2, corresponding to >40 000 cd m−2, well above the requirement for daylight AR applications and optogenetic single-unit activation in the brain

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Hillebrandt, Sabina UNSPECIFIED orcid.org/0000-0002-2628-385X UNSPECIFIED Moon, Chang-Ki UNSPECIFIED orcid.org/0000-0001-8286-5187 UNSPECIFIED Taal, Adriaan J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Overhauser, Henry UNSPECIFIED UNSPECIFIED UNSPECIFIED Shepard, Kenneth L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Gather, Malte C. UNSPECIFIED orcid.org/0000-0002-4857-5562 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-715432
DOI:	10.1002/adma.202300578
Journal or Publication Title:	Advanced Materials
Page Range:	p. 2300578
Date:	20 July 2023
Publisher:	Wiley
ISSN:	1521-4095
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Physical Chemistry
Subjects:	Physics Technology (Applied sciences)
Related URLs:	Publisher
Funders:	Defense Advanced Research Projects Agency (DARPA) under Contract N6600117C4012,, National Institutes of Health under Grant U01NS090596, Leverhulme Trust (RPG-2017-231), Marie Skłodowska Curie individual fellowship (101029807), Alexander von Humboldt Stiftung (Humboldt-Professorship), Engineering and Physical Sciences Research Council under grant numbers EP/L017008/1, EP/R023751/1 and EP/T019298/1
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/71543