Caesium manganese fluoride cubic-perovskite nanoparticles – synthesis, luminescence and magnetic properties

Abstract

Lead halide perovskite materials have outstanding optical properties such as color purity and efficient fluorescence in the visible spectrum. However, the toxicity of lead makes the synthesis, processing, use and disposal of such materials hazardous for humans and the environment. Therefore, the exploration of different perovskite materials containing the transition metal Mn(II) and fluoride anions might lead to more appealing alternatives towards more sustainable and environmentally friendly functional materials. Nanocrystals primarily consisting of cubic CsMnF3 – a polymorph so far only reported at pressures of 3 × 104 bar – were synthesized from manganese(II) acetate and caesium fluoride precursors using a heating-up approach in high boiling organic solvents. The concentration of defects could be tuned by changing the amount of fluorinating precursor CsF, with more defects produced when an excess of CsF was used in the synthesis. The structure, morphology, optical and magnetic properties of the product nanoparticles were studied. Due to their X-ray sensitized fluorescence, likely caused by defects in the crystal structure, these materials are promising for potential applications in dosimetry.Graphical CsMnF3 nanocrystals were synthesized by a heating-up method using stoichiometric or excess quantities of the fluoride precursor CsF to control the concentration of defects (CMF and CMF-d). The obtained nanoparticles exhibited X-ray sensitized luminescence, enhanced by a factor of up to 3.75 after irradiation with X-rays for 2 h.