CALCE Webinar - Are Fatigue-Free Flexible Displays Possible?

Aris Christou
Tuesday, August 11, 2020 11:00 am US EDT

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The field of flexible electronics has achieved numerous applications within electronic systems. However, line out degradation plagues flexible display reliability. In addition, various display needs require harsh environment, reliability, lightweight as well is ideal for integration with a flexible power source or battery. In this webinar, flexible display structures, powered by thin-film cells on the same substrate as the display pixels with improved reliability are reported. The display structure consists of arrays of thin-film transistors on polyethylene naphthalate. The nanoparticle technologies consisting of multiple layers of mixtures of activated carbon and ruthenium (IV) oxide for supercapacitors are reported. The mono-particulate layer process described here is a modified Langmuir-Blodgett trough. We report the processes for a spray-coated zinc nano-powder electrode used as a counter-electrode forming a galvanic cell of extremely high charge storage capacity (>40A-hr/cm2). Hydrated ruthenium oxide as a nano-powder (10-100nm) with a surface area that approaches tens of square meters per gram is layered with nano-powder activated carbon. Thin separating insulating layers are interposed between the RuO2 xH2O and the counter-electrode. As the counter-electrode, thin films of zinc and aluminum, and powders of zinc for surface area enhancement have been applied. These cells are processed on flexible substrates in order to form a totally self -powered multi-pixel flexible display. Current-Voltage characteristics of thin-film transistors biased by the nanoparticle flexible batteries show fast power-on characteristics. The line-out degradation mode of flexible displays has been investigated on test structures with graphene interconnects. The graphene SN fatigue behavior shows the existence of a fatigue limit which can potentially solve the line out defect problem in flexible displays.

About the Presenter: Dr. Christou has more than 150 publications in archival journals and 14 patents (including two pending) and has organized international conferences in GaAs devices, materials, and reliability. Dr. Christou is a Fellow of the IEEE, a Fullbright Fellow, a recipient of the DoD-Berman Publication Awards, and an IEEE Guest Lecturer. Professor Christou was the 2004 recipient of the INEER Achievement Award (International Network for Engineering Education and Research) for achievements in international education and research in engineering, as well as the recipient of the 2007 ASM International Burgess Memorial Award "For his seminal scientific contributions in the field of electronic materials, packaging, and devices." Professor Christou is a member of APS, ASM, TMS, and MRS was the past President of the Federation of Materials Societies from 2004-6 and is presently a member of the FMS Board of Trustees.