Effect of temperature on the optical properties of polyethylenimine-stabilized CdS nanoparticles

An unusually pronounced temperature dependence was found for photoluminescence intensity and energy of size quantization levels of polyethylenimine-stabilized CdS nanoparticles with diameter similar to 1.8 nm in the range 280-353 K. Evidence was given to support the hypothesis that these changes result from the reversible dissociation of a complex of the polymer amino groups with coordinatively unsaturated Cd(II) ions on the nanoparticle surface and the completion of the coordination sphere of these ions by water molecules participating in the non-radiative dissipation of the electronic excitation energy of CdS nanoparticles. Promise for the use of such nanoparticles is found in the development of sensor systems for monitoring the temperature of microvolumes and the diagnosis of heat exchange phenomena.