Preparation And Characterization Of Double Rare Earth Organic Complexes Light Conversion Agents

The rare-earth light conversion agent was a new type of functional material with the ability of converting light, which had be widely used in the fields of optical fiber communication, agricultural film, biological analysis sensor and laser technology, etc.Although europium has been widely used for rare earth light conversion agent with excellent performance of photoelectricity and magnetism, the europium was expensive and emitted single spectra of europium, which not match with plant photosynthesis. Those disadvantages limited europium wildly used in agricultural films. In this paper, rare earth inorganic light conversion agents were synthesized with europium, samarium used as the center, and Al2O3, H3BO3 used as the matrix. A series of rare earth complexes organic light conversion agents were synthesized by using europium as the center, low price rare earth ions, salicylic acid and phenanthroline as organic ligands. Polyethylene light conversion films were successfully prepared with better performance and lower cost. The main contents were summarized as follows:1) Inorganic light conversion agent: Al18B4o33:Eu3+ inorganic rare earth light conversion agent was synthesized by high temperature solid state. The properties were characterized by X ray diffraction analysis, laser particle size analysis and fluorescence spectrum analysis. When n(Al) / n(B) was set at 4.5:1 in reactionmaterials,Al18B4o33:Sm3+ light conversion agent can be excited by the light which wavelength is 200-400 nm, characteristics of the red light was 580-710 nm and highest fluorescence intensity was weak of 735 (a.u.). Al18B4O33:Sm3+ light conversion agent can be excited by the light which wavelength is 200-500 nm,characteristics of the red light was 585-720 nm and the highest fluorescence intensity was about 3032 (a.u.). Compared with Al18B4O33:Sm3+ , the fluorescence intensity of Al18B4O33:Sm3+ was obviously higher, but lower than that of double rare earth organic complex light conversion agent.2) Double rare earth organic complex light conversion agents: Double rare earth organic complex light conversion agents EuxSm1-x(Hsal)3Phen and EuxY1-x(Hsal)3 Phen were prepared by samarium and europium or yttrium and europium, which had a better match with plant absorption spectrum. The properties of the organic light conversion agent were characterized by X ray photoelectron spectroscopy, infrared spectroscopy, fluorescence spectroscopy,thermogravimetric analysis and laser particle size analysis. The excitation intensity reached the maximum value when the light conversion agents were excited by 394 nm UV light and 465 nm blue and green light, When the molar content of Sm3+ was 70 %, the peak intensity of Eu0.3Sm0.7(Hsal)3Phen was reached to the maximum at 646 nm, and the emission light at 646 nm was in good agreement with the absorption spectrum. When the molarcontent of Y3+ is 70 %, the Eu0.3Y0.7(Hsal)3Phen excitation spectrum reached the maximum value at 200-465 nm, the emission spectral intensity reached the maximum value at 585-665 nm, and the optical conversion performance is good.3) Preparation of light conversion films: Eu(Hsal)3Phen,Eu0.9Sm0.1(Hsal)3Phen,Eu0.6Sm0.4(Hsal)3Phen,Eu0.5Sm0.5(Hsal)3Phen,Eu0.5Y0.5(Hsal)3Phen,Eu0.2Y0.8(Hsal)3 Phen and Eu0.1Y0.9(Hsal)3Phen was added into low density polyethylene separately to prepare light conversion films. The fluorescence performance of the films were characterized by fluorescence spectroscopy. Ultraviolet and violet light could be converted into red light by the light conversion films that were suitable for the plant photosynthesis.