Article
The Latest Advances Changing the Prospects for OLED Materials
Published: July 16, 2012 Category: Advanced Materials OLEDs

The technology gaps in the OLED industry have not gone unnoticed by the materials suppliers, which have been providing steady improvements in performance.  Overall, most clearly needed by the OLED industry are materials used in the functional stack – emitters, hosts, transport and blocking materials, etc. – that enable higher efficiency and longer lifetimes at the right color points to achieve proper color gamut (in displays) or the right color rendering index (CRI) and color temperature (in lighting). 

Obviously, US-based OLED materials pioneer Universal Display Corporation (UDC) and its materials partners are at an advantage here, at least with respect to phosphorescent technologies and the superior efficiency that they can provide, and with respect to customization and optimization of auxiliary materials to be used in conjunction with the phosphorescent materials. 

However, a breakthrough by an outside firm based on non-phosphorescent (or at least not on iridium metal cores) could be quite lucrative to the inventing firm as well. Breakthroughs in any of a number of other materials could also translate into a significant opportunity.

The Need for Better Blue Emitters

In Lighting: As we noted above, lifetime is still a critical issue for up-and-coming key OLED applications. Some progress has been made on the color and lifetime of a light blue OLED emitter system that may advance OLED lighting. For example, UDC is now actively commercializing a light blue emitter that delivers 70 lm/W luminous efficacy and an operating lifetime of 30,000 hours (to 70% of initial luminance) in an OLED lighting panel.

While this achievement is notable, the industry still has much to be accomplished.  First, it remains to be proven that this material can be scaled up at the customer with the same results.  Second, even this performance lags behind that required to support a serious business case, i.e., at 100 lm/W and 50,000+ hour lifetimes, for using OLED lighting in general illumination applications.

In Displays: More critically, the lifetime problem has not yet been solved adequately for red, green, blue (RGB) full-color displays, especially with respect to high efficiency deep blue phosphorescent emitters.

In the AM OLED displays on the market today, red phosphorescent emitters are already used preferentially, and green phosphorescent systems are increasingly being adopted as well.  But even in the relatively small, relatively short-lived AM OLED mobile computing applications, the blue emitter system is still dominated by a conventional fluorescent system.

Furthermore, there are no real signs that the industry will make the switch to all-phosphorescent any time soon, other than a vague promise by Samsung to adopt UDC’s phosphorescent blue “as soon as it can be qualified.”

The problem is that the larger-area applications like TVs are expected to have much longer product lifetimes than most mobile computing devices, which today makes differential aging among emitter systems a problem for display engineers and consumers alike. 

NanoMarkets expects that the OLED TV industry will need to make a move toward all phosphorescent to allow the technology to establish a strong foothold in the display market. Solving this problem is a materials related issue. 

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