Temperature effects on the spectral properties of colloidal CdSe nanodots, nanorods, and tetrapods

The temperature dependence of the absorption and fluorescence spectra of colloidal CdSe nanocrystals was compared for three different shapes (dots, rods, and tetrapods) in the range of 4-300 K. While the shift of the fluorescence maximum indicates little dependence on the shape, the authors find that the broadening of the emission spectrum behaves very differently for dots and rods, indicating major differences in the broadening mechanisms for different shapes. Tetrapods behave more similarly to dots, which suggests that the lowest exciton state is centered at the core. (c) 2007 American Institute of Physics.