OLED displays use organic materials that emit light when electricity is applied. OLEDs enable emissive, bright, thin, flexible and efficient displays. OLEDs are set to replace LCDs in all display applications - from small displays to large TV sets.
UDC OLED material performance, 2012
One of the main problems of OLED displays is the limited lifetime of the OLED materials. In past years we have seen great advances in this area, and today OLED materials are quite long lasting - with material lifetime reaching million hours or more.
Blue OLED lifetime
A blue OLED emitter is the most unstable emitter, and blue OLEDs (required to create a full-color display) suffer from short lifetimes. This is especially true for the efficient phosphorescent blue emitter - and today there's still no commercial efficient blue emitter.
The OLED industry is seeking several routes to develop an efficient blue. PHOLED pioneer Universal Display is developing a blue PHOLED, but has yet to find a commercial-ready material. Other promising route is TADF emitter technology.
The latest OLED lifetime news:
HDTVTest posted an interesting interview with Cadmium-Free QD developer Nanosys CEO and president Jason Hartlove. In this long interview Jason discusses the company's technology and recent achievements.
Jason reveals that the company is working on emissive Quantum Dots displays - and he expects to have a full-color monitor-size QLED display prototype ready by the end of 2019. Jason says that they hope to show these display prototypes in private demos at CES 2020.
In March 2018 OLEDWorks launched its first flexible OLED panels, branded as BendOLEDs. The company now announced that the panels are now commercially available - and rebranded as LumiCurve Wave, which is the first panel in OLEDWorks LumiCurve product family.
The LumiCurve Wave is produced on Corning's 0.1mm thin Willow Glass flexible glass substrate. OLEDWorks says that the Wave panels are extremely thin and light and deliver the superb light quality and excellent color rendering that is uniquely achievable with OLED.
An interview with Cynora's CMO Dr. Andreas Haldi - talking about TADF, lifetime, color points and more
German TADF developer Cynora presented its latest blue TADF material in May 2018 - with a CIEy of 0.14, EQE of 20% and a lifetime of 20 hours LT97 at 700 nits. Cynora expects to have blue material in the mass production by 2020.
Cynora's Chief Marketing Offer, Dr. Andreas Haldi was kind enough to answer a few questions we had regarding TADF emitters, the differences between next-generation emitter technologies, lifetime, color points and more.
Kyulux announced that it has developed a new blue Hyperfluoresence/TADF OLED emitter. Kyulux managed to extend the lifetime of the material and reached 100 hours at LT95 (@ 750 cd/m2) while maintaining a high EQE of 26% - 22% at 1,000 cd/m2. The emission wavelength is 470 nm.
Kyulux says that its blue Hyperfluorescence emitter is the world’s top performing material at the moment. Kyulux now aims to work together with OLED panel makers to improve the systems further by optimizing the device structure and the rest of the OLED stack in pilot production lines.
IGNIS developed a new driver chip to enhance OLED compensation process using individual pixel sensing
IGNIS Innovation announced that in collaboration with its partners, the company developed a driver chip that incorporates the ability to sense individual pixels on the panel. This new ability integrates into IGNIS' overall external compensation process and can improve the perofrmance and lifetime of AMOLED displays.
IGNIS says that this new IC is already being used on medium sized panels designed for IT and automobile applications.
Samsung researchers study the degradation of blue PHOLED materials, offer new design strategies for longer lasting blue emitters
Researchers from Samsung Electronics and the Ewha Womans University in Korea collaborated in a new study of the degradation in blue phosphorescence OLED materials. This study demonstrate the importance of controlling exciton-induced electron transfer, and more importantly provides strategies for the design of longer-lasting blue PHOLED materials.
The researchers say that the study reveals the charge-neutral generation of polaron pairs (radical ion pairs) by electron transfer from the dopant to host excitons. According to the study, device lifetime correlates linearly with the rate constant for the annihilation of the radical ion pair.
SEL develops a new Host-Guest system that enables red phosphorescent emitters with 5.4X the lifetime
Researchers from Japan's Semiconductor Energy Laboratory (SEL) developed a novel Host-Guest system that drastically improves the lifetime of OLED emitters. The researchers report that using this system, a deep-red phosphorescent emitter achieved 5.4 times longer the lifetime compared to the same emitter with a conventional system.
The researchers will present the new system at SID DisplayWeek 2018 in May. The new system is not only highly durable, it also satisfies the red chromaticity of the BT.2020 standard.
Taiwan-based Chunghwa Picture Tubes (CPT), in collaboration with European research institute imec (in the framework of the Holst Centre collaboration) have demonstrated an ultra-high resolution OLED display that was patterned using photolithography - without the need for an FMM (metal mask). A photolithography process offers a high aperture ratio, large substrate sizes and good yield control.
The prototype display that was demonstrated is a passive display with a 1400x1400 resolution (or 1250 PPI!) of side-by-side orange and green OLEDs. imec reports that preliminary lifetime investigation shows operation of each color after patterning for a few hundred hours at more than 50% of the original brightness.
A few days ago, Cynora hosted the 2017 International TADF Symposium in Frankfurt, Germany. Cynora reports that about 150 attendees from all over the world listened to experts from the industry and academia and were updated on the latest news regarding TADF OLED emitters.
Cynora itself showed an update on its latest blue emitter. The company now has material that features a CIEy of 0.18 (target - 0.1), EQE of 14% (target 15%) and a lifetime of 10 hours LT97 at 700 nits (target is over 100 hours). Cynora says that development is progressing well and it is confident it will reach its target material performance by the end of the year.
In May 2017 Cynora announced a new blue TADF emitters that achieves a 15% EQE at 1000 nits with an emission peak of 470 nm and a LT97 of > 90 hours (at 700 nits) on a device level. Cynora has stated several times that it aims to commercialize its first highly efficient blue TADF emitter by the end of this year.
According to Cynora, the performance requested from customers is an EQE (at 1000) of over 15%, a lifetime (LT97 at 700 nits) of over 100 hours and a wavelength of 460 nm (color purity FWHM 60 nm).