Spectroscopic Examination and Theoretical Modelling of Fluorescence Spectral Diffusion of Dot-In-Rod Nanoparticles

Here we investigate the photoluminescence properties, more specifically the spectral diffusion, of chemically-synthesized CdSe/CdS particles, which consist of a spherical core enclosed by an elongated shell. Time and spectral resolved data were collected at low temperature to analyze the spectral diffusion of the emission. The observed correlation between the energy and the decay time of the emission was used to develop a theoretical model, which includes migrating surface charges to describe the fluorescence jittering. Our initial model calculations already show a good agreement with our experimental studies. In the next step, the model was refined by the incorporation of strain effects and the geometric parameters as well as different material compositions were investigated in respect to spectral diffusion. One of these possible systems could be ZnSe/CdS, a type-II heterostructure. Further, ZnSe/CdS particles have been synthesized and their spectral diffusion behavior has been compared to their type-I CdSe/CdS counter-part.