Role of Rare earth doping on scintillation enhancement in yellow emitting KZnF₃ nano cubes

Herein, we report the KZnF₃ nanocubes as one of the candidates to get Ce³⁺ doping and down conversion phenomenon under UV photon excitation as well as energetic x-rays to its low phonon energy and unique crystal structure. The hydrothermal method involving aqueous and organic solvents (ethanol and oleic acid) was used to prepare the synthesis of the doped KZnF₃ nanoparticlesKZnF₃ belongs to the cubic perovskite structure with the <!--[if gte msEquation 12]>p m:val="¯"/> style='mso-bidi-font-style:normal'>m style='mso-bidi-font-style:normal'>3m space group (no. 221) showing crystallite sizes around 60 nm by X-ray diffraction and doping of Ce³⁺ up to 2% was found to be consistent with the crystal structure. Transmission electron microscopy suggested the cube-like morphology of nanoparticles with average size distribution around ~ 50 nm and energy dispersive spectroscopy confirmed the uniform distribution of elements. FTIR analysis confirmed the adsorption of the oleic acid ligands on the surface of the nanoparticles. The UV excitation (254 nm) of the undoped KZnF₃ nanocubes showed the yellow luminescence centered at 582 nm, whereas the doping of Ce³⁺ improved the intensity around 580 nm and displayed a very week broad band emission around 350 nm due to f-d transition in Ce³⁺ ion. Further, undoped and doped KZnF₃ nanoparticles were excited by x-ray energies which showed the hot yellow emission band around 580 nm suggesting a huge energy transfer under high energy radiation. The Ce³⁺ doped specimen, like photoluminescence data, showed two components of emission 340 nm due to Ce³⁺ and enhanced 580 nm due to matrix. Additional emission intensity stability test under maximum x-ray flux for 10 minutes showed the stable emission without degradation. The strong room temperature emission at 580 nm and week emission at 340 nm further promotes the exploration of different doping based KZnF₃ nanocubes for a wide variety of applications including displays, solar energy, catalysis and bioimaging etc. and making the example an interesting candidate for x-ray scintillation applications.