Power consumption - Page 6

Researchers from the Université de Rennes in France have developed a simplified PHOLED green emitter that achieves the world's highest efficiency in single-layer PHOLEDs - an EQE of 22.7%.

The researchers, led by Prof. Cyril Poriel, say that the emissive layer was developed using a rational molecular design. The impact of the phosphorescent emitter on the ambipolarity of the charge transport is particularly evidenced and appear as a key concept in the high performance that was achieved.

A few months ago, Japan Display (JDI) announced that it has developed a "historic breakthrough in display technology" - a new OLED deposition process which they refer to as eLEAP, that is said to be cost effective and can be used to create freeform OLEDs that are brighter, more efficient, and longer lasting compared to OLEDs produced using mask evaporation (FMM).

According to a new report from Korea, Samsung Display is interested in JDI's new technique. Interestingly the report shows conflicting views within SDC - some are interested in adopting this new technology, especially at SDC's upcoming 8-Gen IT OLED production line, while others are more interested in preventing SDC's competitors (JDI, or others?) from using it, perhaps by pressuring OLED equipment makers to not offer needed equipment to JDI.

TCL (CSoT) announced that the company has finalized the development of several new OLED technologies, which has been deployed at the company's production lines.

The first technology is LTPO, or Low-Temperature Polycrystalline Oxide, an OLED backplane technology developed originally by Apple. LTPO enables variable refresh rates, and TCL's technology can support a wide range of frequencies, from 1Hz to 144Hz.

Second-generation OLED phosphorescence emission features an internal quantum efficiency of almost 100% - which would normally mean you cannot get more efficient than that.

As Kyulux explains in a recent post, though, phosphorescent suffers from a wide emission spectrum. In order to achieve a good color gamut (for which as narrow-spectrum emission as possible is best) display makers have to filter out the "tail" of the emission. This results in reduced brightness and efficiency.

Idemitsu Kosan announced that it has developed the world's most efficient blue fluorescence OLED emitter system. Idemitsu's new system achieves an EQE of 14% (at current density of 10 mA/cm²), a lifetime of over 400 hours (LT95 @ 50 mA/cm²) and a color point of (0.14,0.08).

The new material system uses a tandem structure of two blue OLED emitter layers. Idemitsu says that by separating the region that causes charge recombination and utilizing TTF (Triplet-Triplet Fusion) it managed to achieve the high light output.

Japan Display (JDI) announced that it has developed a new OLED deposition technology, which they refer to as eLEAP, that is cost effective and can be used to create OLEDs that are brighter, more efficient, and longer lasting compared to OLEDs produced using mask evaporation (FMM). eLEAP also enables OLED freeform deposition. JDI regards its new technology as a " historic breakthrough in display technology".

eLEAP is based on a lithographic method, and does not require any masks. The main advantage seems to be that OLED displays produced by eLEAP technology can achieve an aperture ratio of 60%, compared with FMM OLEDs which achieve a ratio of about 28%. This means that the OLED displays can be driven at lower currents - which extends the lifetime, improves the efficiency and also enables higher-peak brightness when needed.

As we reported last week, LG Display is developing OLED TV panels that utilize a microlens array to increase the light output. LGD unveiled its first prototype display at SID Displayweek 2022.

LGD is showing a 77" 8K panel that features what the company refers to as Meta-lit Lens Array, or MLA technology. The MLA layer increases light output by more than 20%, and the panel achieves a brightness of 2,000 nits. LGD says that the viewing angles is also increased using the MLA technology.

Reports from Korea suggest that LG Display is looking into adopting a microLens array in its large OLED TV panel architecture. The microlens layer could boost brightness by up to 20%, which will also increase efficiency (if brightness is kept as before).

MicroLens array structure, University of Michigan

According to the report, the project is at an advanced stage, and panels with the microLens array could be introduced by the end of this year. LGD will apply the technology to its OLED.EX panels, so brightness could reach up to 1,200 nits. LGD considers this technology as it faces competition in large-area OLED production, from Samsung's QD-OLED panels, for the first time.

This is a sponsored article by Nanomatch

Recent applications of the Nanomatch Toolkit to improve OLEDs:

• Charge carrier mobility
• Charge screening in OLED materials
• Doping
• Excited states in molecular thin films

Attend our talk at SID Display Week (Session 28 on May 11 2022, 10:40 AM) for further information.

Read more:

In 2016, Researchers from Japan's Semiconductor Energy Laboratory (SEL) announced a new OLED device architecture, called ExTET ('exciplex triplet energy transfer'), that can increase the performance of OLED devices. The technology was applied for a patent in 2011.

The ExTET technology, which is a modification of the host material and the EML layer in phosphorescent OLED devices, have since been introduced to commercial AMOLED panels, increasing the efficiency and lifetime of the materials, while also lowering the drive voltage.