Flexible Lighting Technology Nears Commercial Feasibility


Reading time ( words)

Imagine illuminating your home or business with flat, inexpensive panels that are environmentally friendly, easy on your eyes, and energy-efficient because they create minimal heat.

Now imagine how those panels could be used if they were as flexible as paper or cloth; the technology could be bent into shapes, fit the interior or exterior curves of vehicles, even be incorporated into clothing.

In "Flexible organic light-emitting diodes (OLEDs) for solid-state lighting", a team of researchers at Pohang (Republic of Korea) University of Science and Technology reports on advances in three key areas — flexible electrodes, flexible encapsulation methods, and flexible substrates — that make commercial use of such technology more feasible and closer to implementation. The article appears in the current issue of the Journal of Photonics for Energy, published by SPIE, the international society for optics and photonics.

OLEDs show promise as a future light source because of their thinness, light weight, energy efficiency, and use of environmentally benign materials. Companies such as Philips and LG Chemical have begun producing flat OLED panels that produce non-glare, UV-free light but very little heat, with no need for lamp shades or diffusers.

"The future trend in OLEDs is to make them on plastic substrates for flexibility, durability, and light weight. In this work, the authors review the technical challenges and solutions in this important subject," said Franky So, Walter and Ida Freeman Distinguished Professor in Materials Science and Engineering at North Carolina State University, and an associate editor of the journal.

Min-Ho Park and other researchers at Pohang tested a variety of transparent electrodes as flexible alternatives to currently available devices based on indium tin oxide (ITO), which is brittle and increasingly expensive, and identified next steps toward making flexible solid-state lighting commercially feasible:

  • development of a flexible electrode that has high electrical conductivity, high bending stability, few defects, smooth surface texture, and high work function
  • reduction in the water-vapor transmission rate of materials used, to counter the vulnerability of OLEDs to moisture.

OLEDs produce light by sending electricity through one or more thin layers of an organic semiconductor, which may be composed of any of a variety of materials and as small a as a molecule. The semiconductor is sandwiched between a positively charged electrode and a negatively charged one. These layers are deposited on a supporting surface called a substrate, and protected from exposure to the air by a thin layer of encapsulants (traditionally glass).

The Pohang team demonstrated good electrical, optical, and mechanical performance with flexible electrodes fabricated using graphene, conducting polymers, silver nanowires (AgNWs), and dielectric-metal-dielectric (DMD) multilayer structures.

However, various obstacles still remain with these devices’ durability, conductivity, surface roughness, and fabrication cost. Current flexible substrates and encapsulation methods are being explored, with the goal of reducing cost and processing time, and increasing durability.

The Journal of Photonics for Energy covers fundamental and applied research areas focused on the applications of photonics for renewable energy harvesting, conversion, storage, distribution, monitoring, consumption, and efficient usage. Editor-in-Chief Zakya Kafafi is adjunct professor in electrical and computer engineering at Lehigh University.

About SPIE

SPIE is the international society for optics and photonics, an educational not-for-profit organization founded in 1955 to advance light-based science and technology. The Society serves nearly 264,000 constituents from approximately 166 countries, offering conferences and their published proceedings, continuing education, books, journals, and the SPIE Digital Library in support of interdisciplinary information exchange, professional networking, and patent precedent. SPIE provided more than $4 million in support of education and outreach programs in 2014. SPIE is a Founding Partner of the International Year of Light and Light-based Technologies and a Founding Sponsor of the U.S. National Photonics Initiative. http://www.spie.org

Share

Print


Suggested Items

CES 2020: The Intelligence of Things

01/06/2020 | Nolan Johnson, I-Connect007
Show week for CES 2020 starts well ahead of the actual exhibition dates because it is huge. The organizers of CES state that there are more than 4,400 exhibiting companies and nearly three million net square feet of exhibit space. On the floor, you can find 307 of the 2018 Fortune Global 500 companies. Over the week, I-Connect007 Editors Dan Feinberg and Nolan Johnson will bring you some of the most interesting news, products, and announcements from 5G to IoT, semiconductor developments, autonomous vehicle technology, interconnect, fabrication materials, and much more.

NASA Sounding Rocket Technology Could Enable Simultaneous, Multi-Point Measurements — First-Ever Capability

10/21/2019 | NASA
NASA engineers plan to test a new avionics technology — distributed payload communications — that would give scientists a never-before-offered capability in sounding rocket-based research.

For Climbing Robots, the Sky's the Limit

07/15/2019 | NASA
Robots can drive on the plains and craters of Mars, but what if we could explore cliffs, polar caps and other hard-to-reach places on the Red Planet and beyond? Designed by engineers at NASA's Jet Propulsion Laboratory in Pasadena, California, a four-limbed robot named LEMUR (Limbed Excursion Mechanical Utility Robot) can scale rock walls, gripping with hundreds of tiny fishhooks in each of its 16 fingers and using artificial intelligence (AI) to find its way around obstacles.



Copyright © 2020 I-Connect007. All rights reserved.