Regensburg 2007 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 24: Nano structured materials II

MM 24.6: Talk

Wednesday, March 28, 2007, 18:00–18:15, H4

Balancing the White Light Shade of Dual-Color Emitting Nanocrystals — •Sergiy Mayilo¹, Sameer Sapra², Thomas Klar¹, Andrey Rogach¹, and Jochen Feldmann¹ — ¹Photonics and Optoelectronics Group, Department of Physics and CeNS, Ludwig-Maximilians Universität München, Germany — ²Physical Chemistry Group, Technische Universität Dresden, Germany

Semiconductor nanocrystals (NCs) are highly fluorescent with fluorescence quantum efficiencies as high as 80%, being ideal candidates for use in white light emitting devices. Simple mixing of red, green and blue emitting NCs may lead to undesirable changes in color during the lifetime of the device due to different temporal stabilities of the components. Here we present the generation of white light from core-shell-shell CdSe/ZnS/CdSe NCs [1]. These particles have two emission lines: blue (500 nm) from the CdSe shell and orange (612 nm) from the CdSe core. The ZnS layer is used as a spacer between the two emitting regions. The shade of the white light can be controlled during synthesis by varying the thickness of the CdSe shell. The relative intensities of both emission lines are also determined by intra-nanocrystal energy transfer. When the colors are well matched the resulting emission appears as pure white light. The synthesized NCs have 30% quantum efficiency.

[1] S. Sapra, S. Mayilo, T.A. Klar, A.L. Rogach, J. Feldmann, Bright white light emission from semiconductor nanocrystals: by chance and by design, Advanced Materials (in press)