At the edge of display tech evolution

Schematic of transient-electroluminescent device. An AC voltage is applied between the gate (bottom) and source (top) electrodes. Light emission occurs near the source contact edge during the moment when the AC signal switches its polarity from positive to negative (and vice versa), so both positive and negative charges are present at the same time in the semiconductor, creating light. Credit: Der-Hsien Lien et al./Nature Communications

We have witness the amazing progress in making ever thinner televisions, with displays that have been squeezed in the 3rd dimension from 50 cm and more to 1 cm (with a few top of the line “gadged” in the few mm range). At the same time screens have become larger and larger, from the huge 27 inches on the 90ies to the now standard 42 inches and to the ever more common 65″ with market availability up to 100″. Technology made this squeezing and broadening possible. With the CRT technology the 3rd dimension was tied to the dimension of the screen, the larger the screen the more bulky in the 3rd dimension the television had to be, basically putting a limit to the screen dimension.

Moving from 50cm (or more) to 1 cm (or less) is almost a 2 order of magnitude scaling in the 3rd dimension. We have actually reached a point where we have to create a bulge on the screen to plug in the required cables. Recognising this limit have researchers stopped to look for thinner/larger screens? Of course not!

At UC Berkely researchers are pushing the envelope of thinnest by proposing a completely new display technology that, if made industrially viable, would decrease the current thinnest screen by 6 orders of magnitude to deliver a screen consisting of three atomic layers (plus a substrate), way thinner than a hair.

Photograph of a proof-of-concept transparent display (left), and closeups showing the display in off and on states. Credit: UC Berkeley

The proof of concept display consist of a monolayer 3 atoms thick (or thin!) that is completely transparent when inactive and that can emit a specific range of wavelengths (colours) when activated (by a voltage). By changing the atoms in the layer it is possible to generate different wavelengths (colours) and by layering 4 layers it becomes possible to create a colour display (that remains transparent when inactive).

The prototype has a very low efficiency converting just 1% of the power in light (versus 20 to 30% efficiency of today’s LED) but this is normal of any advanced technology. The important thing is that there is no intrinsic technical limit to block an increase of efficiency.

The layer is so thin that can easily adapt to any surface, including our skin, and can resist bending.

Practical applications are probably 20 years away but wouldn’t you expect if when talking about the edge of technology?

About Roberto Saracco

Roberto Saracco fell in love with technology and its implications long time ago. His background is in math and computer science. Until April 2017 he led the EIT Digital Italian Node and then was head of the Industrial Doctoral School of EIT Digital up to September 2018. Previously, up to December 2011 he was the Director of the Telecom Italia Future Centre in Venice, looking at the interplay of technology evolution, economics and society. At the turn of the century he led a World Bank-Infodev project to stimulate entrepreneurship in Latin America. He is a senior member of IEEE where he leads the New Initiative Committee and co-chairs the Digital Reality Initiative. He is a member of the IEEE in 2050 Ad Hoc Committee. He teaches a Master course on Technology Forecasting and Market impact at the University of Trento. He has published over 100 papers in journals and magazines and 14 books.