Synthesis And Study On The Characteristics Of Agricultural Light Conversion Of Re:KY?WO₄?₂(Re=Eu³⁺,Sm³⁺,Eu³⁺/Sm³⁺)

Different wavelengths of light have different effects on plant growth and development.The increasement in the amount of red and blue light radiation promotes the growth of plants,ultraviolet light damages plants and green light causes waste of light energy.The light conversion agent can convert ultraviolet light and green light in sunlight into red light and blue light required for plant photosynthesis,thereby enhancing photosynthesis of plants,promoting plant growth and development,and improving agricultural development.In this paper,Re:KY?WO₄?₂(Re=Eu³⁺,Sm³⁺,Eu³⁺/Sm³⁺)powders were prepared by hydrothermal method assisted organic active agents.The phase,morphology and fluorescence properties of the powders were characterized by X-ray diffractometer,scanning electron microscope and fluorescence spectrometer.The effects of different controllable factors on the morphology,luminescence properties and light conversion properties of Re:KY?WO₄?₂(Re=Eu³⁺,Sm³⁺,Eu³⁺/Sm³⁺)powders were investigated.,the results are as follows:?1?Acetylacetone,CTAB and SDBS were selected as surface active agents respectively.The micro-nano-tungstate potassium silicate powder was prepared by hydrothermal method.The results showed that KY?WO₄?₂ crystal could be synthesized under three different surfactant conditions.The?220?crystal plane is the strongest peak,and the flaky KY?WO₄?₂ is assembled into a globular shape,but the spherical integrity,flower sphere size,specific surface area and crystallinity of KY?WO₄?₂ have different effects under different surface activities.When 10ml acetylacetone,0.5g CTAB or 0.06g SDBS was added,the integrity of the flower sphere assembly decreased.The spherical particle size was 4.5?m,5?m and 3?m,respectively;the specific surface areas were 36.932 m²/g,31.677 m²/g and 28.574m²/g,respectively;crystallinity is 75.98%,70.6%and 67.9%,respectively.?2?The difference in morphology of KY?WO₄?₂ under different surfactants has an effect on luminescence.The fluorescence performance showed that the sample with10ml of acetylacetone had the strongest luminescence intensity.Under certain conditions,the higher the crystallinity,the better the dispersibility,the largest specific surface area,the better the globular integrity,and the better the fluorescence performance.?3?Different rare earth doping and its concentration have different effects on morphology and luminescence properties.When the single-doped Eu³⁺ions is 45%,the KY?WO₄?₂ flower sphere has good dispersibility,the strongest luminescence intensity,and high intensity red light emission?612 nm?.When the single-doped Sm³⁺ions is 5%,the fluorescence performance is the best,and a red light emission based on650 nm is obtained.When the co-doped Eu³⁺/Sm³⁺ratio is 4:1,the particle size is smaller,the fluorescence intensity is the strongest,and the range of emitted light is wider.?4?The surfactant promotes the formation of flower globular KY?WO₄?₂.The surfactant changes the crystal habit of KY?WO₄?₂ crystal,and the crystal plane grows anisotropically to form a flake;the lamellar structure has a high specific surface area and surface energy,and the small lamellar structure grows at the expense of amorphous precipitates or small particles to form a primary flower-like structure;the flower-like structure grows in a concentric layer mode,and the edges of many sheets form a flower-like structure.The contact area of adjacent sheets is small,and the surface energy is reduced.Finally,the self-assembled structure of the sheet generates a spherical KY?WO₄?₂ in the form of the lowest energy.?5?Sm³⁺and Eu³⁺have absorption peaks in both the ultraviolet and green regions,emitting red-orange light and achieving light conversion.Sm³⁺has sensitization effect on Eu³⁺.The excitation spectrum of co-doped Eu³⁺/Sm³⁺contains absorption transitions of Eu³⁺and Sm³⁺,which coincide with the excitation lines of Eu³⁺and Sm³⁺,and some Sm³⁺ions deliver energy to Eu³⁺ions in the excited state.The sensitization effect enhances the transition emission of Eu³⁺ions.The co-doped Eu³⁺/Sm³⁺has an absorption peak superimposed in the ultraviolet and green regions,and emits high-intensity red-orange light,which is more compatible with the chlorophyll absorption spectrum.