Facile synthesis, magnetic, electrical and photoelectric properties of layered quaternary chalcogenides K2FeCu3Q4 (Q = S and Se)

Abstract

Layered chalcogenides have attracted much attentions due to their unique physical properties. Herein, two novel layered quaternary chalcogenides K₂FeCu₃Q₄ (Q = S and Se) with the ThCr₂Si₂-type structure have been synthesized via a facile hydrothermal approach. Their structures were confirmed by XRD, XPS and TEM. The magnetic studies revealed that K₂FeCu₃S₄ nanoparticles show a superparamagnetic behaviour at low temperature while K₂FeCu₃Se₄ microcrystals exhibit a weak ferromagnetic behaviour with a high magnetic transition temperature. The temperature dependence, ρ(T) is semiconducting for all the compounds and explained well by the variable range hopping (VRH) rather than the adiabatic small polaron hopping (SPH). The band gaps of K₂FeCu₃Q₄ are in the range of 0.99–1.28 eV. Their photoelectric responses were also characterized, which demonstrated their potential for application in photovoltaic devices.