Technical / Research - Page 15

Researchers from RUDN University in Russia have synthesized new OLED emitter compounds. These compounds seem to be phosphorescent emitters, based on copper and silver atoms.

The researchers say that the compound platform they created can lead to efficient and cost-effective OLED emitters, and also offer a special molecular geometry that can enable freedom-of-design for developers.

Researchers from Korea's Yonsei University has developed a 3D printing technique that can be used to deposit transparent OLED displays on any shape. The new technique 3D prints both the support structure and the 3D screen electronics.

The method is based in Digital Light Processing (DLP) system that prints the transparent plastic frames, and then uses an electrohydrodynamic jet (e-jet) printer to create the OLED layers as seen in the image above.

A new company has recently been launched in Poland, to commercialize a new family of TADF OLED compounds. Noctiluca, which takes its name from a bio-luminescent marine creature, was established a few months ago with aims to be the world's first company to produce a commercial-ready blue TADF emitter.

Noctiluca's story begins with an innovative organic DSSC solar cell platform that was developed at Synthex, an organic chemistry development platform company based in Torun, Poland. A few years ago the researchers turned their attention to light emitting materials (which are quite similar to the light harvesting materials used in solar panels) and intensive research culminated in a promising family of new TADF compounds - which was then spun-off as Noctiluca,

Researchers from the Max-Planck-Institute for Polymer Research (MPI-P) have built upon new understanding on organic electronic material defects to suggest ways to design higher efficiency OLED materials.

The researchers explain that they have discovered that clusters of water inside organic semiconductors can function as hole traps, and oxygen clusters can capture electrons in hole-dominated organic semiconductors. Even a small number of such water and oxygen defects can cause highly unipolar charge transport and harm the efficiency of the materials.

LG Electronics performed an interesting test comparing an OLED TV to an LCD LED TV to analyse the physical and emotional responses of viewers. The test was done on identical twins in the UK (Henry and William Wade), which viewed a Game of Thrones episode on LG's OLEDE9 TV and an 2013 LG LCD LED TV.

LG used Realeye's AI platform to analyse the facial expressions, head movements and body language of the twins, in addition to their hear rate. LG says that the test revealed that its OLED TV held 25% more attention than its 2013 TV, and that happiness was three times higher. The LG OLED TV provided a 15% more intense experience from a positive emotional standpoint.

Researchers from Japan's Kyushu University developed new OLED devices made by integrating OLED emitters with thick layers of hybrid perovskite materials. The researchers say that such a device structure to enable lower-cost production and better viewing angles in OLED displays.

OLED devices usually use a very thin layer of organic materials, as these are poor conductors, which makes production more difficult and also leads to cavity effects which distorts the emission color. The thick perovskite-OLED hybrid layer (which is around 2,000 nm thick) are more easily processed compared to thin film layers while still being highly conductive.

Researchers from TU Dresden developed a new method to extract trapped photos from OLED devices. The idea is to generate controllable nanostructures with directional randomness and dimensional order. This method is said to significantly boost the efficiency of white OLED devices. The researchers report that it is possible to achieve an external quantum efficiency of up to 76.3%.

To produce the nanostructures, the researchers use reactive ion etching, a facile, scalable and lithography-free method. In addition to these advantages, the method enables to specifically control the topography of the nanostructures by adjusting the process parameters.

Researchers from the Max Planck Institute for Polymer Research (MPI-P) have developed an efficient OLED device that is comprised of a single organic material layer - replacing the normal stack of 5-7 layers in modern OLED devices.

The researchers managed to create this OLED device by using a TADF material (CzDBA, diboron based TADF) and by using a newly developed charge injection strategy. The OLED device features a low operating voltage (2.9V at 10,000 cd/m^₂, an EQE of 19% (at 500 cd/m²) and a lifetime of 1,880 hours at 50% (for 1,000 cd/m²). The color of the device is greenish-yellow.

Researchers from the Imperial College London developed a new class of PLED materials that exhibit circularly polarized luminescence. Basically this means that the new materials emit polarized light which could make for more efficient Polymer-OLED devices as none of the light will be blocked by the external anti-glare circular polarizer added to the display.

In 2013 researchers from the ICL has reported they are researching the usage of Helicenes as emitter materials in PLED devices that also emit circularly polarized light - the researchers termed these devices CP-OLED (Circularly-Polarized OLED). Helicenes materials are thermally-stable polycyclic aromatics with helically-shaped molecules.

The US Department of Energy (DoE) has granted $1.1 million to Penn State University professors Chris Giebink and Michael Hickner for a new project to increase the efficiency of OLED lighting panels.

The researchers, collaborating with OLEDWorks in this project (and previous ones as well), aim to find a way to lower the refractive index of the organic materials which will increase the external efficiency of OLED devices. The basic idea is to insert other molecules and blend them with the existing OLED materials which lower the refractive index without adversely affecting the properties of the original molecules.