New findings move flexible lighting technology toward commercial feasibility

September 03, 2015

BELLINGHAM, Washington, USA, and CARDIFF, UK - 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: 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.
-end-
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.

The journal is published digitally in the SPIE Digital Library, which contains more than 430,000 articles from SPIE journals, proceedings, and books, with approximately 18,000 new research papers added each year.

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

SPIE--International Society for Optics and Photonics

Related Photonics Articles from Brightsurf:

Tiny device enables new record in super-fast quantum light detection
Researchers from the University of Bristol's Quantum Engineering Technology Labs (QET Labs) and Université Côte d'Azur have made a new miniaturized light detector to measure quantum features of light in more detail than ever before.

Researching the chips of the future
The chips of the future will include photonics and electronics; they will have a bandwidth, speed and processing and computing abilities that are currently unthinkable.

Intelligent nanomaterials for photonics
2D materials - combined with optical fibres - can enable novel applications in the areas of sensors, non-linear optics, and quantum technologies.

Parylene photonics enable future optical biointerfaces
Carnegie Mellon University's Maysam Chamanzar and his team have invented an optical platform that will likely become the new standard in optical biointerfaces.

Photonics researchers report breakthrough in miniaturizing light-based chips
Electrical engineers at the University of Rochester have created the smallest electro-optical modulator yet, using a thin film of lithium niobate bonded on a silicon dioxide layer.

Recent advances in 2D, 3D and higher-order topological photonics
A research team from South Korea and the USA has provided a comprehensive review covering the recent progress in topological photonics, a recently emerging branch of photonics.

Topological photonics in fractal lattices
Photonic topological insulators are currently a subject of great interest because of the features: insulating bulk and topological edge states.

Novel "dual-resonant method" in 2D materials can spur advances in the field of photonics
Scientists at Daegu Gyeongbuk Institute of Science and Technology, Korea, have developed a new process that provides an ultrafast process of photon generation in two-dimensional materials.

A different slant of light
Giant clams manipulate light to assist their symbiotic partner.

Photonics: From custom-built to ready-made
An international collaboration team of University California, Santa Barbara (UCSB), California Institute of Technology (Caltech) and EPFL has developed an integrated technology that may revolutionize photonic systems.

Read More: Photonics News and Photonics Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.