SBIR Phase II: Highly Efficient, Long Lifetime, and Inexpensive Nanocrystal Light Emitting Diodes (LEDs)

This Small Business Innovation Research (SBIR) Phase II project will advance the performance of light emitting diodes based on semiconductor nanocrystals (NanoLEDs) to the same level of that of organic/polymer light emitting diodes (OLEDs). The key parameters of NanoLEDs targeted for this Phase-II program are 2000 hours operation lifetime, above 200 Cd/m2 brightness, and 0.5-2% external quantum efficiency. The Phase-II program will improve the performance of the NanoLEDs through a unique design of the nanocrystal thin layer in the devices. This design enables the ligands of all nanocrystals to be inter- and intra-particle cross-linked, which results in the thermally stable nanocrystal thin films required for high performance devices. The three dimensionally cross-linked ligands are short and have quasi-conjugated electronic structures, instead of the traditional long aliphatic ligands. This choice aims to dramatically improve the charge injection and charge transport in the NanoLEDs. New types of nanocrystals to be used will diminish the re-absorption and energy transfer in the densely packed nanocrystal thin films identified in literature. With the committed support from a state agency and extensive collaboration with mainstream industry it is expected to commercialize this technology in the display and lighting industry within five years. The commercial potential of NanoLEDs is enormous. NanoLEDs possess nearly all of the advantages of OLEDs, but with readily tunable and narrow emission profiles. OLEDs are currently being used in active commercial development. The commercial goal in the Phase-II is to boost the performance of the NanoLEDs to at least the same level of that of the polymer LEDs, the low end of OLED devices. The first generation of NanoLEDs will be used in portable electronic devices. When the lifetime of NanoLEDs is extended over ten years, they will be used for other display technologies and in the lighting industry. NanoLEDs will one day change the way we see the world. Based on industry estimation, the near-term market for flexible LEDs, including NanoLEDs, will be $5 billion in 2005. After they are adapted to the mainstream of the flat panel graphics and lighting applications, the market size is going to be at least tens of billions.