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U.S. Department of Energy Energy Efficiency and Renewable Energy
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Materials Degradation Analysis and Development to Enable Ultra Low Cost, Web-Processed White P-OLED (Phase I)

Investigating Organization

Add-Vision Inc.

Principal Investigator(s)

J. Devin MacKenzie

Subcontractor

None

Funding Source

Small Business Innovation R&D, Phase I

Award

DOE Share: $98,855

Contract Period

6/20/07 - 3/19/08

Add-Vision ("AVI") has developed a path for specialty SSL using a doped Polymer Light-Emitting Diode (POLED) device structure, enabling printing of devices with low capital equipment and operating costs. Devices made with AVI's approach are efficient, thin, flexible, and robust and AVI has plans with licensing partners to commercialize this technology in entry level specialty SSL applications. However, additional performance improvements, which would be made possible through the degradation analysis and material and process development proposed in the early stages of this STTR program would enable commercialization of this technology in a broader range of applications of interest to DOE and their licensees for interior buildings, safety and night lighting.

AVI will combine its expertise in printed POLED devices, materials, processing and electrical characterization with the materials analysis and synthetic capabilities of Lawrence Berkeley National Laboratory to identify the primary efficiency degradation mechanisms for doped POLED devices (Phase-I), then develop a next generation materials set based on this analysis for high efficiency, longer lifetime printed devices. Upon achievement of the performance and lifetime improvements, Phase-II and III emphasize product demonstration, process scale-up and pilot manufacture with continuous engagement with their manufacturing licensee(s) and product development customers.

AVI's POLEDs are anticipated to accelerate the early adoption of POLED technology in SSL and improve energy savings and overall product performance in future building applications, including electronic signage, architectural lighting, safety lighting, emergency and portable lighting, and other specialty lighting products. The print-based manufacturing approach of this OLED technology has inherently low cost capital equipment and operating adoption, product start-up, and large scale web manufacture of SSL that could leverage the resources of the U. S.'s more than 40,000 printing operations.

Since the beginning of the project, Add-Vision has seen substantial improvements in device performance through morphology improvements, formulation optimization of LEP materials, and improved encapsulation technology. We have now repeatedly demonstrated fully air printed P-OLED devices of >1000 hrs lifetime with 100 Cd/m2 maximum luminance, meeting our initial brightness lifetime goals. Work is ongoing to improve operating voltages and further elucidate the next limiting degradation issue. This includes ongoing work with purified organic materials and microscopy work made available by LBNL
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(a)
On the left is a square consisting of patches of orange, yellow, and a few black and one white patch. On the right is a square that is fairly uniform orange or blackish orange, with a few black patches and a few tiny yellow patches.

(b)
A chart with Luminance (Cd/sq m) on the vertical axis, and Time in hours on the horizontal axis. A slightly undulating line representing Luminance begins in the lower 80s Cd/sq m, rises to 100 Cd/sq m at 100 hours, slowly falls at 1,000 hours, and at 1,100 hours drops more precipitously to reach about 60 Cd/sq m at 1,200 hours. Another line, representing Voltage, begins at around 10 volts, slowly rises to reach about 18 volts at 1,000 hours, and then rises more quickly, reaching 31 volts at 1,200 hours.

Figure 1. (a) Atomic force micrographs showing the improvements in surface morphology that have been achieved through printed LEP formulations development [right] as compared to the previous formulations [left] Note that the X and Y scales are 8 microns and the z height scales are 40nm per division on the left and 20 nm per division on the right. The lifetime test data for an encapsulated part made from these formulations is shown in (b) demonstrating 1000 hrs operation in air under constant current driving conditions.