Preparation,Properties And Application Of Novel Ion-doped Gd₂MoO₆ And Yb₆O₅F₈ Upconversion Luminescent Materials

Upconversion luminescent?UCL?materials had been attracted extensive attention in recent years due to their great application prospects in solid ultraviolet,cell imaging,temperature sensors,color display sources and solar cells etc.UCL was a process of converting absorbed multiple low-energy photons into a high-energy photon through a radiative transition.Commonly,the near-infrared light was converted into visible or ultraviolet light.However,the luminous efficiency of the UCL material in practical applications was relatively low,which was affected by many factors,such as the doping mode of ions,excitation mode and matrix materials.Therefore,the novel ion doped Gd₂MoO₆ and Yb₆O₅F₈ UCL materials were synthesized by mild sol-gel method and hydrothermal method,respectively.The UCL properties,mechanism and applications of two materials were explored.?1?Most articles reported on the luminescent intensity was improved by replacing the cations in the matrix materials.However,there were few studies on the replacement of anionic groups,and was no report about the simultaneous substitution of the anionic groups and cations in the matrix material.Therefore,Gd₂MoO₆ was selected as the matrix,and its anionic group and cation were partially substituted.?WO₆?^6-/La³⁺single and co-doped Gd₂MoO₆:Er³⁺/Yb³⁺upconversion nanoparticles?UCNPs?were synthesized by sol-gel method.It was found that under single wavelength excitation,strongest,the red emission intensity increased by 4.8?980 nm?and 6.6?1550 nm?times,respectively.On the other hand,the red emission of?WO₆?^6-/La³⁺single and co-doped Gd₂MoO₆:Er³⁺/Yb³⁺exhibited"1+1>2"synergistic effect upon the simultaneous excitation at two-wavelengths,the possible mechanism process was proposed sample was found to have good thermosensitivity,and have excellent selectivity to the dimethyl methylphosphate?DMMP?.?2?Yb³⁺ions were often used as sensitizers owing to their large absorption cross section upon 980 nm excitation.However,the research on the fluorine oxides rich in Yb³⁺ions with low phonon energy was scarce.Therefore,a novel self-sensitized Yb₆O₅F₈ crystal was synthesized by hydrothermal method in this paper.And the effects of p H on the crystal phase,morphology and particle size were firstly investigated.In addition,it was found that the green or red phosphors with high color purity could be obtained by Yb₆O₅F₈:Er³⁺crystal had strong red light monochromaticity due to the energy transfer?ET?and energy back transfer?EBT?process between Yb³⁺and Er³⁺.And it exhibited synergistic effect upon the simultaneous excitation at two-wavelengths.Therefore,biomedicine and solar cells.