Back in August we noted a few points about the development and adoption of blue phosphorescent OLED materials (“Singing the Blues”) and also indicated some hesitancy about the excitement that had gathered around the pending development of a blue phosphorescent OLED emitter material next year.  While the development of same by a number of companies, including Universal Display (OLED), Samsung Display (pvt), Sumitomo Chemical (4005.JP), Idemitsu Kosan (5019.JP), Merck (MRK), and Lumiotec (pvt), as well as a number of well-known universities, continues, the actual adoption of a blue phosphorescent material into a commercial OLED stack is a more difficult task and one that is likely not to adhere to the aggressive timelines than many hope for.
Universal Display began reporting commercial revenue from phosphorescent emitters in late 2005, primarily from its red emitter.  Previously the company’s sales came from developmental materials sold to customers and developmental contracts.  The first color OLED smartphone was the Samsung (005930.KS) X120, released in 1Q 2004, which had a 1.8” OLED display, was able to reproduce 65,000 colors, with a resolution of 128 x 128 pixels., and the following year BenQ (2352.TT) released the A520, which sported a 1.5” OLED display (128 x 128) and a smaller 96 x 96 display.  To compare that to what is available currently, the Xiaomi (1810.HK) 14 Pro released this month has a 6.73” OLED display that can reproduce 68 billion colors and has a resolution of 3200 x 1440 pixels.
We have been tracking sales of Universal Display’s OLED materials for more than 10 years and while the company announced its first commercial green phosphorescent green emitter material in the summer of 2010, Samsung Display, UDC’s biggest customer did not release a smartphone using both red and green phosphorescent emitters until the Galaxy S4 in April of 2013, almost 3 years later.  We expect Samsung Display had integrated the green emitter into the display stack for some time before the stack was stable enough to be used commercially, and while the OLED industry is far more adept at making stack material changes, we expect there will be a learning curve with blue phosphorescent emitter material when it is made available commercially.
At a seminar yesterday in South Korea, UBI research, a local consultancy, stated that Samsung Display had set a goal of applying blue phosphorescent OLED material to devices in the 2nd half of 2025, rather than in mid-2024 as previously expected.  We believe this is in reference to materials being developed by SDC, and while we assume they are working with UDC on that development, that remains unconfirmed.  UBI went on to state that they believed the current version of SDC’s blue phosphorescent emitter material is not efficient enough to be used as is, although they believe that SDC would be willing to use a more efficient version, even if the lifetime was only 55% of the fluorescent emitter materials it will replace.  Given that color point (deep blue), efficiency, and lifetime are all variables that determine the commercial success of an emitter material, it has been difficult to ‘blend’ the three major parameters to create a commercially viable blue phosphorescent emitter material.
To complicate matters further, the other components of the OLED stack, most of which are developed and produced by other material suppliers, must also work efficiently with the OLED emitter materials, and that combination must be formulated by the panel producer.  UDC and others will develop their blue phosphorescent emitter with host materials, but there are typically at least 4 layers (usually more) of additional materials that create the environment under which the emissive materials work best, so even if a panel producer decides to use a commercial blue phosphorescent emitter, all of the layers in the stack are likely to be redesigned to produce the most efficient stack combination, a time consuming task, and one that involves considerable testing. 
Why Blue?  The quest for a blue phosphorescent emitter material is not a frivolous one, as a proper phosphorescent blue emitter will improve the stack’s power efficiency.  Estimates seem to range for an improvement of between 20% and 35%, although we expect that the actual result will depend on both the blue material specs and the other stack emitters and materials.  Anything that can reduce the power consumption of a mobile device is of immense value to device designers who can add additional hardware or functionality or reduce the size of the battery, while maintaining or improving the overall display specifications. 
Why has it been so hard?  UDC and others have been on the trail of a blue phosphorescent emitter material for almost as long as commercial OLED materials have been around, but like other ‘blue’ structures, such as blue LEDs, the characteristics that create blue light are specific to what are known as ‘high bandgap’ materials.  In an OLED device, ‘holes’ (think: ‘anti-electrons’) are injected into the stack at the Highest Occupied Molecular Level (HOMO), while electrons are injected at the Lowest Unoccupied Molecular Level (LUMO), with the space between those two ‘points’ called the bandgap.  As the world of electronics always strives toward a neutral state, the two ‘migrate’ to the bandgap mid-point and when they pair, they release light energy and cancel each other.  The frequency (color) of that light energy is proportional to the size of the ’gap’ between HUMO and LUMO, with larger gaps creating higher (blue) frequencies and small gaps creating lower (red) frequencies.
Unfortunately, the larger the bandgap, the more unstable the materials tend to be, which means they have short lifetimes, just as in nature animals or insects with high metabolic rates tend to have shorter lifetimes than those with slower rates, and this has been a fundamental problem for OLED material scientists.  In theory, a lighter blue should be more stable and have a longer lifetime, but a deep blue is essential to balance the phosphorescent red and green already being used in RGB OLED displays, so the quest to find a material with a large bandgap with a stable structure continues.  Eventually a material will be found that meets the necessary criteria, but once it becomes commercialized, it will take time to find its way into OLED stack, just the way green phosphorescent emitter material did, along with the more predictable issues surrounding cost, availability, and IP that overhang current OLED emitter materials.  It’s coming and its going to create a stir when it does, but aside from the initial hoopla, blue phosphorescent OLED emitter material is just a part of the OLED stack and will be subject to the same starts and stops as other OLED materials.

Taiwan based Digitimes indicated in an article that Samsung Display (pvt) and LG Display (LPL) are decreasing their reliance on outside sources for organic materials used to produce flexible OLED displays.  While this is ultimately true, that South Korean firms would ideally like to have ultimate control over the materials used in the production of flexible (and other) OLEDs, the article did little to specify any changes that have not been mentioned previously, generally citing mergers and investments by both producers that would help them gain the necessary IP to bring production of flexible OLED materials to Samsung SDI (006400.KS) and LG Chem (051910.KS) respectively.

The article specified that both producers obtained polyamide varnish from Japanese supplier Ube Industries (4208.JP) and a number of other TFT backplane production materials from South Korean suppliers ENF Technology (102710.KS), Dongjin Semichem (005290.KS) and Dongwoo Fine-Chem (pvt), a division of Sumitomo (8053.JP), none of whom struck us as different than would have been expected.  Further, deposition materials, a far more important component of the OLED production process, were specified coming from Idemitsu Kosan (5029.JP), Universal Display (OLED), Dow Chemical (DOW), and Merck (MRK), but hinted that the Samsung purchase of Novaled and an investment in Sun Fine Chem, a division of Hodogaya Chemical (4112.JP) were leading to the acquisition of IP that would allow these organics to be made internally, and finally that flexible substrates and cover glass were sourced from 3M (MMM) and Corning (GLW) respectively.

While there are a great number of materials and suppliers used in the OLED production process, this article did little to shed any light on current or potential changes that have been implemented by South Korean producers.  Samsung purchased Germany based Novaled for $347m back in August 2013, a company known for its ‘PIN OLED’ material that is used to enhance the electron mobility of certain OLED stack layers.  It doesn’t replace other stack components, but works with other stack materials to give better overall stack results, and an investment by Samsung in SFC (Sun Fine-Chem) a division of Hodogaya Chemical, goes back to 2011.

We believe that the only thing relating to OLED materials that has changed recently, other than the usual vying for a position in the OLED stack of these South Korean producers, is the change in backplane made by Samsung Display earlier this year.  This change, to the M8 backplane did make some changes in OLED material suppliers, with red host material moving from Dow to Duksan Neolux (213420.KS) and green host moving from Samsung SDI to Nippon Steel (5401.JP), while other emitter and host materials suppliers remained the same.  While on a long-term basis, OLED producers are always looking to reduce costs, using their leverage to pit one supplier against the other, that doesn’t always lead to using home country or in-house suppliers, as is seen in the change above where green host moved from an in-house South Korean supplier to a Japanese supplier, and both producers evaluate many materials from suppliers to find the right combination of performance and cost.  If a local or in-house supplier can meet those needs, everyone is satisfied, if not, there is no hesitation on the part of Samsung Display and LG Display to use outside suppliers, and that has not changed over the last few years.