Going a step beyond the organic light-emitting diode (OLED) concept, in which the emissive electroluminescent layer of a light-emitting diode (LED) is a film of organic compound that emits light in response to an electric current, researchers are making great strides in LED testing with nanoparticles. Scientists recently developed a method to employ standard electrical switching techniques to create color displays from pairs of nanoparticles that produce different colors of the spectrum. This innovative technology has ramifications for luminaires, solid state lighting, and just about all lighting applications.
The research has come out of Rice University’s Smalley-Curl Institute and was supported by the National Science Foundation, the Welch Foundation, the American Chemical Society, the Air Force Office of Scientific Research, and the Smalley-Curl Institute.
Electrochemically Constructed Drawbridges
Electrochemically-constructed drawbridges can be opened and closed merely by applying or removing the voltage in light-activated nanoparticles. The traditional use of gold nanoparticles has many benefits but historically has been limited thus far regarding the creation of distinct reversible colors. Naturally, then, researchers are pleased about the new possibilities.
How Electrochemical Nanoparticle Color Switching Works
Here’s how the color switching works: Pairs of metal nanoparticles absorb light and convert it into plasmons (a quantum measurement of plasma oscillation), which then scatter to a frequency on the spectrum. What’s more, minor changes in the back-and-forth motion of the plasmon shifts the color, with bigger frequencies meaning more distinct changes in color. Researchers have found that gold nanoparticles can produce a variety of colors while remaining very stable. The price of gold is not a large issue as it only takes an infinitesimal amount of gold to create an incredibly bright color.
To state it simply, the process is the creation of an electrochemical bridge across the inter-particle gap that produces a completely reversible transition between the capacitive and conductive plasmonic couplings.
Electrochemically bridging nanoparticles to form reversible color modifications has ramifications for all kinds of LED testing, including CIE 127, LM-79, LM-80. To stay on top of the latest innovations in spectroradiometers that test night vision compatibility, record measurements (LED, OLED, IRED and display), detect spectral response, measure internal and external quantum efficiencies, and more, contact Gooch & Housego today at 800-899-3171.