Roll-coating organic LED is first step to cheaper fabrication

Light-emitting-diode (LED) displays are typically made by the batch using vacuum deposition chambers, but researchers at Pacific Northwest Laboratory (Richland, WA) recently demonstrated a fast and continuous method for depositing a film of the active layer of small-molecule organic LEDs onto a flexible plastic substrate.

This proof-of-principle experiment used roll-coating, a method developed for plastics, paper, and other roll goods. The light-emitting small-molecule organic dopant was added to a tris-8-(hydroxyquinoline)-aluminum host and then sprayed onto the substrate as a liquid. The process allows the manufacturer to switch liquid sources without stopping the coater.

Click here to enlarge image

The demonstration showed that doped films can be produced by premixing the host and dopant instead of carefully controlling co-evaporation rates. The resulting film showed quantum efficiencies similar to vapor-deposited films. Researcher Paul Burrows reports that spectroscopy shows no residual emission from the host, which is "important for color purity and as a demonstration that we got enough of the dopant in."

If the encapsulate and electrical contact layers can also be deposited by this method, then entire large-area displays could be made very quickly and relatively inexpensively.

Yvonne Carts-Powell is a freelance writer living in Belmont, MA; e-mail: yvonne@nasw.org.

50 YEARS OF SOLID-STATE LASERS


A long way from the ruby laser

Most Popular Articles

Webcasts

Multichannel Spectroscopy: Technology and Applications

This webcast, sponsored by Hamamatsu, highlights some of the photonic technology used in spectroscopy, and the resulting applications.

Handheld Spectrometers

Spectroscopy is a powerful and versatile tool that traditionally often required a large and bulky instrument. The combination of compact optics and modern pa...

Fracking, climate change, and lasers:  new tools to reduce fugitive methane emissions

This webcast, sponsored by Hamamatsu Corporation, covers recent developments and field deployments of compact quantum-cascade-laser (QCL)-based methane senso...

Opportunities in the Mid-IR

The technology for exploiting the mid-IR is developing rapidly:  it includes quantum-cascade lasers and other sources, spectroscopic instruments of many...
White Papers

Narrow-line fiber-coupled modules for DPAL pumping

A new series of fiber coupled diode laser modules optimized for DPAL pumping is presented, featur...

Accurate LED Source Modeling Using TracePro

Modern optical modeling programs allow product design engineers to create, analyze, and optimize ...

Optical Isolators Improve Engraving Performance of Pulsed Fiber Lasers

The deleterious effects of back reflections on pulsed fiber lasers used in marking and engraving ...
Technical Digests

ADHESIVES, SEALANTS, AND COATINGS: Solutions for optical technologies

A vast array of optical systems of various types and degrees of complexity require the use of adh...

WAVELENGTH-SWEPT LASERS: Dispersion-tuned fiber laser sweeps over a 140 nm range for OCT

By eliminating the use of mechanical tunable filters and instead tuning by intensity-modulation i...

Keeping pace with developments in photonic materials research

For demanding or custom spectroscopy solutions, care must be taken in selecting and integrating a...

HIGH-POWER FIBER LASERS: Working in the kilowatt regime

High-power materials-processing fiber lasers are available in an increasing variety of forms, as ...

Click here to have your products listed in the Laser Focus World Buyers Guide.

RELATED PRODUCTS

Social Activity
  •  
  •  
  •  
  •  
  •  
Copyright © 2007-2014. PennWell Corporation, Tulsa, OK. All Rights Reserved.PRIVACY POLICY | TERMS AND CONDITIONS