Technical / Research - Page 16

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.

Researchers from RIKEN, the University of California, San Diego and others have developed a new mechanism to enhance the efficiency of OLED devices. The basic idea is to manipulate the electron spin to control the OLED exciton formation - basically lowering the OLED voltage so that only triplets and formed instead of a combination of singlets and triplets.

The researchers demonstrated this principal using an organic molecule called 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA), placed on a metal-supported, ultrathin insulating film. By measuring the emission spectrum, they could monitor the exciton type - and show that at a low voltage, only triplets are formed.

The Holst Centre announced that it will show several new fingerprint sensor innovations at Display Week 2019 next week. The research center will show a new high-resolution (500 PPI) under-the-display sensor that uses the Center's proprietary collimator technology as well as an in-display sensor concept that uses photolithography patterning to integrate the OLED and organic photo diodes (OPD) pixels side-by-side.

The Holst will also showcase a new over-the-display (suitable for LCDs) transparent sensor which at 70% the center says is the world's most transparent fingerprint sensor.

OLED driver maker MagnaChip launched its latest 28 nm OLED Display Driver IC for smartphone displays. MagnaChip says that it is using the world's most advanced process for OLED drivers, which enables it to achieve a 20% reduction in form factor compared to its previous 40 nm process.

In addition to the size reduction, the new process also enabled MagnaChip to reduce the voltage from 1.1V to 1V, which reduces the power consumption by more than 20%, and it also reduces the EMI levels (again, by 20%) which improves the phone's call quality.

Researchers from the Korea Advanced Institute of Science and Technology (KAIST) developed a self-powered wearable and washable OLED display device. The whole device is fabricated on textiles and the efficient OLED devices are driven by polymer solar modules.

Both the OLED device and the polymer solar panels are sensitive to moisture and oxygen, and regular OLED encapsulation will not protect such a device when washed. The researches designed a new washable encapsulation barrier using both ALD and spin coating. The device is flexible (curvature radius of 3 mm) and survived 20 washing cycles of 10 minutes each with little change in performance.

Professor Homas Teets from the University of Houston has been awarded a $589,000 National Science Foundation (NSF) CAREER Award to explore new synthetic strategies for producing photoactive organometallic compounds.

Specifically, Teets will use the award in three research areas - efficient and long-lasting blue OLEd emitters, near-infrared (NIR) emitting compounds and photocatalysts for organic synthesis capable of light-induced electron transfer. The grant will also fund educational projects aimed at children from kindergarten through high school.

TCL unveiled that the company is developing a new hybrid display technology that uses a blue OLED emitter coupled with red and green QD emitters. All three emitter materials will be combined and printed using ink-jet printing technology. TCL calls this technology H-QLED and this could prove to be the technology of choice for TCL's future high-end emissive TV displays.

It seems as TCL believes that commercial-level red and green QD emitters will be achievable in the future, but blue QD emission will be more difficult to develop, and hence it will rely on OLED emitters. TCL did not disclose more details - but this R&D effort is being performed at the company's Juhua Printing platform.

In 2014 we reported that the Tai-Yah (also called Atayal) tribe, the "dark tribe", has started to test National Tsing-Hua University's blue-free OLED lighting panels (produced by WiseChip).

These early candle-light street OLEDs were not suitable for that environment, and NTHU researchers say that mountain dew rapidly shorted the wires. But not NTHU has stepped up its efforts and teamed up with First-o-Lite to produce a new version of its panels. This time the researchers are positive that its new panels will enable the entire village to adopt blue-hazard free lighting,