Technical / Research - Page 28

Researchers at the US DoE's Ames Laboratory developed a near ultra-violet (UV) OLED device that can be used as an on-chip photosensor. They say that this is the first time that light can be captured and manipulated at around 400 nm - or near the invisible end of the spectrum.

The researchers envision a tiny chip that can act as a whole spectrometer - so it can measure the absorption or luminescence spectrum of anything that can absorb or emit light. There are many applications for such a sensor - for food safety, water quality, medical diagnosis and more. This near-UV OLED development is a step towards that goal.

Finding an alternative for ITO as a transparent electrode is one of the major flexible OLED challenges. A few days ago, The Faunhofer Institute FEP demonstrated an OLED device that has a graphene electrode, developed as part of project GLADIATOR.

The Fraunhofer developed the device in collaboration with Spain-based Graphenea, which supplied the CVD-produced monolayer graphene. Graphene-Info posted an interview with the project's coordinator who further explains the technology, why graphene is promising and what are the challenges that still has to be solved before graphene transparent electrodes can be commercialized.

The Faunhofer Institute FEP is going to demonstrate an OLED device that has a graphene electrode, developed as part of project GLADIATOR. The Fraunhofer developed the device in collaboration with Graphenea, which supplied the CVD-produced monolayer graphene.

This first demonstrator is a small OLED device. The partners in this project now aim to create a larger-sized OLED with an active area of 42 cm². They also plan to develop a fully-flexible transparent OLED, with an active area of 3 cm².

Professor Bjorn Lussem from Kent State University received a $180,000 grant from the Binational Science Foundation to continue his development of an OLED display that is driven by a vertical organic transistor.

Professor Lussem explains that vertical transistors use less voltage so they are more power efficient. A vertical design also means you can make higher density displays. Professor Lussem's partner in this reserach is Professor Nir tessler from Israel's Technion institute for technology.

US-based Pixelligent has been researching light extraction materials for OLED lighting panels for a long time, and the company now officially announced a new family of OLED lighting products.

The PixClear Zirconia nanocrystal family of high index materials enable revolutionary light extraction and efficiency for a wide variety of OLED Lighting applications. PixClear materials can be incorporated into OLED lighting panels as an internal light extraction and smoothing layer, delivering more than twice the amount of light currently extracted in OLED lighting devices.

Researchers from Korea's Ulsan Institute of Technology announced that they have developed a new technique that can improve the efficiency of Iridium-doped phosphorescent emitters by more than 30 times.

The team explained that this dramatic increase in efficiency was achieved by a new method to synthesize molecules - which resulted in "stronger" molecules. More precisely, the researchers created an emitter molecule in which the two carborane units were thethered by an alkylene linker.

This is a guest post by SCM's business developer Fedor Goumans

To further improve the efficiency and life-time of organic light-emitting diodes (OLEDs), ultimately the properties of underlying materials need to be tweaked at the molecular level. In materials science, as in other fields, modeling has become a more wide-spread tool integrated with experiments for a holistic research & development approach.

In particular, high-throughput screening computational screening may considerably reduce experimental costs for synthesizing and testing new materials. At the molecular level there are a few properties that are important for OLED life-time and efficiency. A simplified set up for an OLED device is depicted in Figure 1. The charge mobility and light emission properties can be predicted with computational chemistry, as explained below.

Researchers from Germany's Goethe University discovered that graphene doped with boron atoms feature an intensive blue fluorescence - which means that this new material may prove to be useful in OLED devices.

The Boron doping changes the graphene in two ways. First of all, it shifts the fluorescence into the desirable blue spectral range. It also improve the capacity to transport electrons. The new material is reportedly not sensitive to oxygen and moisture, unlike most boron-containing graphenes.

ITRI and Orbotech signed an agreement to jointly develop solutions for flexible display production. In the first stage, ITRI will use Orbotech's inspection technology to identify production bottlenecks in flexible AMOLED processes.

ITRI says that they are confident that flexible devices are the future of the display industry, and that flexible OLEDs will bring next generation form factors such as foldable tablets and wearable devices.

FlexEnable and Chunghwa Picture Tube (CPT) demonstrate an OTFT full-color flexible AMOLED display manufactured by using FlexEnable's low-temperature process and CPT's RGB OLED technology.

The glass-free prototype display (which you can see above) is a full-color AMOLED that operates at 60Hz and is only 125 microns thick. This is a great achievement, but it's not clear whether CPT aims to commercialize such displays any time soon.