Fabrication And Broadband Up-conversion Luminescence Of Mn²⁺-Yb³⁺ Codoped Glass Ceramic

Up-conversion luminescence material is a host that can emit high energy photon by absorbing low energy photon.So far,up-conversion luminescence materials have been widely used in bio-imaging,solid laser,display,lighting and solar cells.Owing to the rapid commercialization of diode laser,up-conversion luminescence has been developed to be a research hotspot.In the previous investigations,the doping ions of up-conversion luminescence material were mostly rare earth ions.The emission bands of rare earth ions are narrow and the emission peaks are fixed in several common wavelengths,which prevent the application of up-conversion luminescence material in unconventional wavelengths.The emissions of transition metal ions are broad and sensitive to their local environment.Thus,it is possible to obtain broadband and tunable emissions in transition metal ions doped materials.In the past,some studies about up-conversion emission of transition metal ions in low temperature have been reported.Recently,researchers have obtained up-conversion emission of Mn²⁺-Yb³⁺codoped crystals at room temperature,which facilitates the application of up-conversion luminescence material.Comparing to crystal,glass exhibits high optical transmittance,excellent machinability and low cost,it is a good matrix for fiber laser and 3-D display.However,there has no report about broadband up-conversion emission in glass by now.In this work,Mn²⁺-Yb³⁺codoped glasses were prepared to achieve broadband up-conversion emission of Mn²⁺ions.Then,the glass ceramics were prepared to obtain enhance up-conversion emission.Finally,the up-conversion and energy transfer mechanism were discussed by the investigation of emission spectra.In this work,firstly,the Mn²⁺doped fluosilicate precursor glass was prepared.The glass ceramic was prepared by heat treatment.It was proved that KZnF₃ nanocrystals have precipitated among the glass ceramic by the XRD and TEM results.It was noticed that Mn²⁺ions have enter KZnF₃ crystal lattices and the emission in glass ceramic was enhanced according to the excitation and emission spectra.Yb³⁺doped fluosilicate precursor glasses and glass ceramics were prepared.It was proved that KZnF₃ nanocrystals have precipitated among the glass ceramic by the XRD results.For investigating the emission mechanism of Yb³⁺,the up-conversion emission spectra excited by 980 nm laser were measured.Comparing to precursor glass,the emissions in glass ceramic were enhanced,indicating that Yb³⁺ions have entered KZnF₃ crystal lattices.Finally,Mn²⁺-Yb³⁺codoped glasses and glass ceramics were prepared.Excited by 980nm laser,the up-conversion emissions of Mn²⁺and Yb³⁺ions were both observed.The emission color of glasses can be regulated by changing the concentration of SiO₂ or Yb³⁺ions.Therefore,the multicolor up-conversion emission can be achieved in the glass.Comparing to glass samples,the up-conversion emission of Mn²⁺and Yb³⁺ions were both enhanced in glass ceramic samples.Thus,the emissions in glass ceramic were more tunable.