Study of the Phase-Evolution Mechanism of an Fe–Se System at the Nanoscale: Optimization of Synthesis Conditions for the Isolation of Pure Phases and Their Controlled Growth
Monika Ghalawat, Pankaj Poddar
Abstract
The iron selenide (Fe–Se) family of nanoparticles (FexSey—where x/y ranges from 1:2 to 1:1) has been fabricated by a thermal decomposition method. The control over solution chemistry has been developed by intensively investigating the effect of reaction parameters by means of wide-angle X-ray scattering, leading to the rich insights into the phase-evolution mechanism of the Fe–Se system. The phase transformation followed the FeSe2 → Fe3Se4 → Fe7Se8 → FeSe sequence in the temperature range of 110–300 °C. The deep mechanistic insight helped in the identification of optimized conditions needed to crystallize the individual phase of the Fe–Se system as well as control of the morphology, crystalline phase purity, and thermal stability of the obtained Fe–Se nanoparticles.