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LG claims to have solved the blue PHOLED puzzle with a new tandem OLED display technology

Fluorescent and phosphorescent layers stacked together (Image Source: LG)
Fluorescent and phosphorescent layers stacked together (Image Source: LG)
Unlike the tandem OLED displays used by Apple's screens, which stack two WRGB layers, LG's latest tandem OLED tech combines fluorescent and phosphorescent layers to improve the efficiency of the blue pixels, boosting overall brightness and reducing power consumption by 25%.

More energy efficiency OLED screens could soon be possible with a new LG solution based on tandem display technology, which is also supposed to solve the blue fluorescence inefficiency.

Initial LG designs released in the early 2010s included organic blue, red and green subpixels based on fluorescence light emission. These first implementations certainly proved superior to LCDs and eventually even to plasmas as the contrast and color purity was better.  However, the energy efficiency was considerably lower, and due to the higher power required to make the OLEDs as bright as LCDs, burn-in problems emerged as the biggest con for the technology. 

Meanwhile, current displays, be they W-OLED or QD-OLED, are way less prone to burn-in, since the red and green pixels now use phosphorescence light emission, which also increases power efficiency. Unfortunately, the blue OLEDs are still based on fluorescence and display makers have been trying to come up with a blue phosphorescent OLED (PHOLED) solution for several years now. 

Universal Display was supposed to launch a stable blue PHOLED by the end of 2024, yet it had to delay the launch to 2025 because the solution is not yet stable enough. LG is trying to tackle the problem in a different way. Instead of entirely replacing the blue OLEDs with PHOLEDs, LG managed to develop a stable solution that combines a fluorescent layer with a phosphorescent layer for the blue pixels. Fluorescent blue pixels have a typical efficiency of around 25%, but with the new tandem technology, LG is pushing the efficiency close to 100%, and this means the blue pixels can get brighter with less energy, which in turn could boost overall OLED display brightness and reduce power consumption by 25%. 

Apparently, this tandem solution would also eliminate the need for a white subpixel, so LG’s future OLED displays could actually have no white dilution and higher color purity that matches or even exceeds Samsung’s QD-OLED color gamut. Of course, Samsung is not sitting on its hands either as it announced a similar technology shortly after LG’s tandem display press release. Samsung, however, has not yet completed development of its solution, which combines PHOLEDs with TADF (thermally activated delayed fluorescence).

When it comes to availability for the new tandem OLED displays, LG stated that it “plans to evaluate the performance for mass production within the year,” so mass production will most likely be scheduled for 2026 and only for smartphones at first. Samsung has not yet commented on any such plans, but Universal Display could still be first to market if it manages to come up with a stable blue PHOLED next year.

Samsung's tandem and TADF solutions (Image Source: The Elec)
Samsung's tandem and TADF solutions (Image Source: The Elec)
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> Expert Reviews and News on Laptops, Smartphones and Tech Innovations > News > News Archive > Newsarchive 2024 08 > LG claims to have solved the blue PHOLED puzzle with a new tandem OLED display technology
Bogdan Solca, 2024-08-27 (Update: 2024-08-27)