Power consumption - Page 9

Researchers from Dresden's Technical University (TUD) developed a new OLED device structure that combine vertical organic permeable base transistors (OPBT) and OLEDs materials - organic permeable base light-emitting transistor, or OPB-LET.

The new design successfully combines the function of a highly efficient switching transistor and an organic light-emitting diode. The OLED transistors (OLETs) are three-terminal devices combining a thin-film transistor with a light-emitting diode. Unlike previous OLETs, the OPB-LET offer high performance, thanks to the permeable base electrode located at the center of the device. The electrode forms a distinctive optical microcavity and so regulates the charge carrier injection and transport.

Last month Samsung Display announced that it has designed a new OLED stack (its M11 stack) that is 16% more efficient compared to its currently OLED stack. The first phone to adopt the new OLED materials will be the Galaxy S21 Ultra.

Anandtech posted an interesting and what seems to be comprehensive review of the Galaxy S21 Ultra display, comparing it to Samsung's previous generation panels. As you can see in the chart above, the results show that the new OLED stack is actually 26% to 31% more efficient when showing a full white screen. The brighter the display, the more efficient the new stack is compared to SDC's previous M10 OLED stack.

Samsung Display announced that it has employed new materials in its latest OLED stack that enables the display to be 16% more efficient compared to its currently OLEDs. The first phone to adopt the new OLED materials will be the Galaxy S21 Ultra.

SDC did not reveal much about the new materials beyond saying that the new architecture "speeds up electron flows in the display’s organic layers". SDC says it uses a new OLED material, which seems to have been developed in-house (although SDC also says it has been 'closely collaborating with global material companies' to increase its competitive edge). SDC holds over 5,000 OLED material patents.

OLED material developer Cynora announced that it achieved a breakthrough in its deep-green TADF material, which it brands as cyUltimateGreen. The new material delivers an efficiency of over 20% (EQE), a lifetime of 400 hours (LT95@15mA) and a color point and emission spectrum that matches today's DICI-P3 standard (Cynora does not specify the exact number).

Cynora further announced that is now making test kits of the new deep-green emitter available to its customers. Display makers can now start testing and verification using the new material. Cynora says it will also 'soon' follow with a deep-blue TADF solution.

Researchers from Osaka University developed the best performing heavy-metal-free room-temperature phosphorescence (RTP) OLED emitters.

The researchers say that the new emitter (called SiAz), made entirely out of carbon, hydrogen, nitrogen, and silicon atoms, combines the mechanisms of TADF and RTP to create an efficient emitter system.

LG Display announced that it has developed and employed new OLED technologies, including new OLED materials and a new OLED device structure (with a new added layer) that enabled it to improve the efficiency of its large-area WOLED panels by around 20%. This enabled LGD to increase the brightness of its OLEDs.

The first display to adopt this new structure and materials is the company's 77-inch OLED panel, but LGD will also apply it to its other panels over 2021. LGD also announced that it will start producing 83-inch and 42-inch OLED TV panels, that will join its existing 48-, 55-, 65-, 77- and 88-inch models.

Researchers from the Imperial College London have devised a method to create strong chiral light emitting polymers OLEDs. These OLED devices emit efficient polarized light - which means that they could be used to create OLEDs without an anti-reflection polarizer filter and thus enable higher efficiency displays.

The researchers discovered that using thin films of aligned polymer LED devices shaped like fusili pasta it is possible to emit high chirality light.

Researchers from Stanford university in collaboration with Samsung's Advanced Institute of Technology (SAIT) developed a new OLED structure that enables resolution of up to 10,000 PPI, high brightness and a cost-effective production process.

In the new so-called Metaphotonic OLED structure, the panel is produced on a base layer of reflective metal with nanoscale corrugations. This 'metasurface' can manipulate the reflective properties of light and thereby allow different colors to resonate in the OLED sub-pixels.

MicroLED technology is regarded by many as a highly promising display technology, that could rival OLED in many applications in the future. We have been following microLEDs since 2018 via MicroLED-Info and are indeed excited by the progress and potential of this display technology.

Peak EQE of RGB micro-LED as a function of LED chip size (source: Crystals)

One of the most talked-about advantages of microLED displays compared to OLEDs is the power efficiency. MicroLEDs are based on in-organic LEDs, which are inherently much more efficient than organic LEDs.

Researchers at Universal Display, developed an OLED device with plasmonic decay rate enhancement that dramatically increase device stability. By including a nanoparticle-based out-coupling scheme to extract energy from the plasmon mode, the researchers managed to maintain the device efficiency.

The device used an archetypal phosphorescent emitter to achieve a two-fold increase in functional stability at the same brightness as a reference conventional OLED device and extracted 16% of the energy from the plasmon mode as light.