Manipulating emission of CdTeSe quantum dots embedded in synthetic opals

Photonic crystals (PCs) are the object of great interest due to the possibility, for appropriate PCs, to modify and control light propagation and even to influence the emission properties of an emitter, such as its emission diagram and its life time. One of the most common approaches to prepare 3D PCs takes advantage of the spontaneous self-organisation of spherical colloidal particles. Large opals have been prepared by the sedimentation method and the size of the balls has been adjusted so that the pseudo-band gap of those PCs lies in the same region than the emission band of CdSe/ZnS nanocrystals. Diagrams of radiation and the modification of the spontaneous life time of the embedded nanocrystals will be presented and discussed. It is found that, for the opal-CdSe/ZnS nanocomposites, the emission intensity decreases and the luminescence decay time increases in the spatial directions, in which the spectral positions of the photonic band gap and the luminescence peak of the quantum dots coincide. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim