SBIR Phase I:Cadmium-free nanocrystals based light emitting diodes for full color flat panel displays

This Small Business Innovation Research Phase I project will develop cadmium (Cd)-free semiconductor nanocrystal (quantum dot)-polymer nanocomposite light emitting diodes (LEDs) that are compact and lightweight and have superior imaging performance and long lifetimes. Polymeric LEDs (PLEDs) provide these advantages, and also feature the advantage of cost-effective solution processability; as a result, PLEDs are expected to replace liquid crystal displays (LCDs) and cathode ray tubes (CRTs) in many existing applications. In addition, these devices have the potential to enable new product forms and applications. However, current PLED technology has some disadvantages, including limited emitting colors, broad and red-tailed emission peaks, low efficiency, and short lifetimes. The proposed Cd-free QD based PLEDs promise to increase the number of colors (by 54% over the NTSC standard color gamut), allowing high color diversity and accuracy for the viewer. This Phase I effort will focus on the development of ultraviolet/blue emitting PLEDs. The follow-on Phase II project will focus on developing full-color devices with the performance to meet the standards necessary for commercial display devices and lighting products. The broader impact/commercial potential of this project will be to enable more extensive use of PLEDs in various electronic devices and replace less-efficient LCDs, which convert only 10% of the input energy into light. The fabrication of LCD displays is also a high-cost and energy consuming process. Replacing LCDs with PLEDs produced at a lower cost will reduce energy consumption and greenhouse gas emissions. Due to their superior features, Cd-based quantum dots (QDs) are being extensively pursued for next-generation LED applications. However, Cd is very toxic and has been linked to a number of human health problems. Meanwhile, production, manipulation, and waste treatment of Cd materials is expensive and can be deleterious to the environment due to the toxicity of Cd-containing materials. The success of this project will benefit society by eliminating the use of Cd-based QDs in LED applications, leading to improved human health and reducing environmental pollution.