Established in 2020 Sunday, April 2, 2023

Coupling light and matter to ensure optimum brightness for displays
The team has been able to realize polariton-based OLEDs with application-relevant efficiency and brightness for the first time. Image courtesy: Professor Malte Gather and Dr Andreas Mischok.

ST ANDREWS.- Researchers at the University of St Andrews, working with colleagues at the University of Cologne, have discovered a way of coupling light and matter to ensure optimum brightness and color of the latest TVs and smart screen displays without sacrificing the device's efficiency.

Lead investigator Professor Malte Gather, of the University of St Andrews School of Physics and Astronomy, a member of the Scottish Universities Physics Alliance (SUPA), explained, "Displays made of organic light-emitting diodes (OLEDs) have long entered the consumer market on all scales—from large TVs to high-resolution smartphone screens.

"However, as the display industry prepares for the next generation of devices with even higher color saturation, brightness and efficiency, scientists are facing several challenges. Inherently, organic light emitters show broad emission spectra due to their intrinsic disorder—a property that limits the available color space and color saturation for high-end displays.

"The emission spectra of OLEDs can be adjusted by the use of color filters or optical cavities, but this either comes at the cost of efficiency or leads to a strong dependence of the perceived color on viewing angle."

The researchers have now demonstrated that a fundamental scientific principle—the strong coupling of light and matter—can be utilized to modify the emission spectra of OLEDs in a manner similar to the use of a microcavity, but without inheriting the strong viewing angle dependence that typically accompanies such designs.

Professor Gather said that by placing the OLED stack between thin mirrors made from metallic materials already widely used in the display industry, the coupling between light and the organic material can be significantly enhanced. However, this coupling would typically lead to reduced device efficiency.

To avoid this, the researchers added a separate thin film of strongly light-absorbing molecules, something one would usually find in organic solar cells but so far not in OLEDs. This additional layer maximized the strong-coupling effect and thus created a hybrid light-matter particle, referred to as polariton, but crucially without substantially reducing the efficiency of the light-emitting molecules in the OLED.

Dr. Andreas Mischok, the first author of the present study, added, "Through the creation of polaritons, we are able to inherit some advantageous properties of matter, including their significantly reduced angular dependence."

While there have been reports on polariton-based OLEDs in the past, they have been plagued by very low efficiency and brightness, which has hindered any real-world applications and kept them confined to the world of fundamental research. With the new strategy, the team has now been able to realize polariton-based OLEDs with application-relevant efficiency and brightness for the first time.

Professor Gather added, "With a performance in the same range as OLEDs used in commercial displays, but with much-improved color purity and color stability under varying view angles, our polariton-based OLEDs could be of great value to the display industry."

In addition to being of interest for next-generation displays, the on-demand and efficient creation of large numbers of polaritons can be utilized for a multitude of applications from lasers to quantum computing.

The study is published in the journal Nature Photonics.

Today's News

March 19, 2023

Antibody fragment-nanoparticle therapeutic eradicates cancer

Satellite powered by 48 AA batteries and a $20 microprocessor shows a low-cost way to reduce space junk

Immune-cell booster for cancer patients

DNA treatment could delay paralysis that strikes nearly all patients with ALS

Scientists discover giant insect genome

Team successfully generates mouse models for two subtypes of multiple myeloma

Coupling light and matter to ensure optimum brightness for displays

"Denoising" a noisy ocean

Losing a key type of pancreatic cell may contribute to diabetes

How fishermen benefit from the reversing evolution of cod

Climate change creates 'win-win' between bald eagles and farmers

Genetic causes of three previously unexplained rare diseases identified

Humans bite back by deactivating mosquito sperm

Scientists develop energy-saving, tunable meta-devices for high-precision, secure 6G communications

Electroactive bacterium generates well-defined nanosized metal catalysts with remarkable water-splitting performance

Researchers discover a new approach to harvesting aerial humidity with organic crystals

3D-printed revolving devices can sense how they are moving

'Terminator zones' on distant planets could harbor life, astronomers say


Editor & Publisher: Jose Villarreal
Art Director: Juan José Sepúlveda Ramírez

Tell a Friend
Dear User, please complete the form below in order to recommend the ResearchNews newsletter to someone you know.
Please complete all fields marked *.
Sending Mail
Sending Successful