|
Marcus Müller, Nikolai Gaponik, Tobias Otto, Vladimir Lesnyak, Paul Mundra, Alexander Eychmüller
Physikalische Chemie/Elektrochemie, TU Dresden, 01062 Dresden, Germany Generating warm white light by color conversion of the blue and the UV part of the spectrum is a huge and promising research field. Since up to 22 %[1] of the energy consumption of industrialized countries is used for lighting, a replacement of the currently used, comparably ineffective incandescent bulbs and fluorescent lamps by LEDs would contribute a large amount to global goals in the reduction of energy consumption. Currently, mainly rare earth doped materials are used as phosphors. Those materials mostly show relatively broad emission spectra with up to 100 nm FWHM and spectral tailing[2]. Moreover, the supply of rare earths, which are the emission centers, is mostly controlled by a monopolist who already reduced the amount which is exported. Therefore, rare earth free phosphors based on quantum dots became of more interest. This includes the possibility to adjust the emission color of the phosphor by varying the size of the quantum dots used. As demonstrated in present work the problem of the photodegradation of the nanoparticles can be overcome by incorporation them into a gas proof crystalline host matrix. The obtained composite materials can be dispersed in silicones, commonly used as encapsulating agents for the semiconductors in LEDs, which makes them a stable, easy to prepare and efficient candidate for a new generation of phosphor materials. [1] US Department of Energy (DOE) 2006 Solid-State Lighting Research and Development Portfolio; Multi-year program plan FY'07-FY'12 (Chicago: Navigant Consulting) [2] IEEE JOURNAL ON SELECTED TOPICS IN QUANTUM ELECTRONICS, VOL. 8, NO. 2, P.339 |
|