Dynamics of Ternary Cu–Fe–S₂ Nanoparticles Stabilized by Organic Ligands

Abstract

Chalcopyrite-type (Cu-Fe-S 2 ) ternary nanocrystals stabilized by long aliphatic chain ligands could be considered as isolated hard nano-objects dispersed in soft network of organic ligands. The main attention was paid to the behavior of the particles whose average size was varied in a controllable manner from 3 to 20 nm. Dynamics of nanoparticles was studied by applying Mössbauer spectroscopy. The fast dynamics could be described by two-level environment. Deeper level (atomic) was practically the same as for bulk material except Debye temperature, but the higher level (particle motion) was described by the classical harmonic oscillator with the spring constant dramatically softening with increasing temperature. Such behavior led to fast decrease of the fraction detectable by Mössbauer spectroscopy with increasing temperature. The induced internal oscillations within particle by surrounding thermal bath additionally contribute to the shift of measured spectra. Slow dynamics was characterized by the thermally driven overdamped harmonic oscillator motions. In addition, the long range-like diffusion of particles was seen. No significant rotation of particles was found within the accessible temperature range.

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“…The broad spectral component of Fe­(IO 3 ) 3 - r shows some manifestation of thermally dependent electronic relaxation phenomena. However, the microscopic mechanism responsible for the relaxation (e.g., spin-phonon and spin–spin interactions) or thermally controlled iron ion dynamics associated with the oscillations is difficult to predict …”

Colloidal Synthesis and Thermoelectric Properties of CuFeSe2 Nanocrystals

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Experimental Studies Reveal Bacteriophages Can Affect Precipitation of Mineral Phases

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