Final Report: Highly Bright, Heavy Metal-Free and Stable Doped Semiconductor Nano-Phosphors for Economical Solid State Lighting Alternatives

EPA Contract Number: EPD08064
Title: Highly Bright, Heavy Metal-Free and Stable Doped Semiconductor Nano-Phosphors for Economical Solid State Lighting Alternatives
Investigators: Battaglia, David
Small Business: Nanomaterials & Nanofabrication Laboratories
EPA Contact: Manager, SBIR Program
Phase: II
Project Period: May 1, 2008 through April 30, 2010
Project Amount: $224,997
RFA: Small Business Innovation Research (SBIR) - Phase II (2008) Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Water and Wastewater

Description:

The purpose of this SBIR Phase II research was to progress the technical development and to determine the commercial potential of using heavy metal-free doped semiconductor nanocrystals (D-dots) as non-scattering nanophosphors for use in phosphor conversion type white LEDs for general illumination lighting applications. The long-term goal for this effort is to improve efficiencies and reduce costs of white LEDs, eventually yielding cost-competitive and efficiency-competitive, energy-saving, mercury-free solid state lighting (SSL) alternatives to energy-wasting incandescent bulbs and mercury-containing fluorescent lamps.

Summary/Accomplishments (Outputs/Outcomes):

It was found that improvements to the synthetic design for the Mn and Cu doped D-dots resulted in values of photoluminescence (PL) quantum yield (QY) near to or equal to that of bulk rare-earth phosphors. With appropriate surface protection/modification, D-dots could be incorporated into encapsulant materials, such as silicones, and retain near 100% of their original PL QY while remaining optically clear. Poor photostability under intense excitation light exposure was found to be a major technical concern when oxygen was present. Studies conducted under oxygen-free conditions, however, resulted in vastly improved photostability even under intense excitation. Based on these findings, LED based SSL devices were fabricated using D-dots as cool-to-warm white light converters and D-dot mixtures as white light emitters starting with near UV-LEDs as the excitation source.
 

Conclusions:

It appears from these results that D-dots can work in combination with as well as replacements for existing rare-earth phosphors. This research has commercial applications in the lighting industry, especially in the area of improvements to phosphor technology for phosphor conversion type white LEDs used for general illumination purposes by either working in combination with existing phosphors or fully replacing them in LED-based lighting devices. NN-Labs envisions from its results that such nanophosphor-based LEDs can be efficient enough and cheap enough to replace both inefficient incandescent lamps and fluorescent lamps that contain the heavy metal mercury in several lighting applications.


Journal Articles on this Report : 3 Displayed | Download in RIS Format

Other project views: All 3 publications 3 publications in selected types All 3 journal articles
Type Citation Project Document Sources
Journal Article Chen D, Viswanatha R, Ong GL, Xie R, Balasubramaninan M, Peng X. Temperature dependence of "elementary processes" in doping semiconductor nanocrystals. Journal of the American Chemical Society 2009;131(26):9333-9339. EPD08064 (Final)
  • Abstract from PubMed
  • Journal Article Viswanatha R, Battaglia DM, Curtis ME, Mishima TD, Johnson MB, Peng X. Shape control of doped semiconductor nanocrystals (d-dots). Nano Research 2008;1(2):138-144. EPD08064 (Final)
  • Full-text: Springerlink PDF
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  • Abstract: Springerlink
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  • Journal Article Zeng R, Rutherford M, Xie R, Zou B, Peng X. Synthesis of highly emissive Mn-doped ZnSe nanocrystals without pyrophoric reagents. Chemistry of Materials 2010;22(6):2107-2113. EPD08064 (Final)
  • Abstract: ACS
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  • Supplemental Keywords:

    Sustainable Industry/Business, Scientific Discipline, RFA, Pollution Prevention, Technology for Sustainable Environment, Sustainable Environment, Energy, Environmental Engineering, Economics, nanotechnology, nano-phophors, solid state lighting, alternative materials, alternative lighting,  LED lighting, Nanophosphors, Phosphor Conversion, Doped Semiconductor Nanocrystals, Doped Quantum Dots, RFA, Scientific Discipline, Sustainable Industry/Business, POLLUTION PREVENTION, Sustainable Environment, Energy, Economics, Technology for Sustainable Environment, Environmental Engineering, alternative lighting, nanotechnology, alternative materials, energy efficiency, solid state lighting


    SBIR Phase I:

    Highly Bright, Heavy Metal-Free, and Stable Doped Semiconductor Nanophosphors for Economical Solid State Lighting Alternatives  | Final Report