Nm Red Phosphor Compound Light Conversion Films, Characterization And Application

Nano composite luminescent plastic (NCLP) was prepared by mixing nano-phosphor and organic polymer. There have been evidences that the greenhouse made by the plastic film containing special photoluminescent materials, which is so called sunlight-conversion film (SCF), may considerably increase the yield and quality of the products. In this thesis, nano-particles of MS:Eu (M=Ca,Sr) and Ca_0.8Zn_0.2TiO₃:Pr³⁺,Na⁺ were synthesized and characterized. Furthermore, nano composite sunlight-conversion film (NCSCF) mixing CaS: Eu nano-particles and PE was investigated.Generally, the red persistent phosphor is synthesized by the solid-state reaction at high temperature. The temperature of the solid reaction is so high that products synthesized become conglomeration easily, which results in the particles are big and no uniform. To meet the need of application of the phosphor, the products have to grind. As a result, the luminescent centers of the phosphor are destroyed and the luminescent brightness of the phosphor falls. Taking the relation between luminescent performance and granularity of the phosphor into account, considering the request of actual application of the phosphor, we believe the phosphors will have new performance that the tradition phosphors have not when the granularity of the phosphor falls to nano-scale.The red persistent phosphors: alkaline-earth metals sulfides activated with Europium have been studied long before. However, alkaline-earth metals sulfides cannot be synthesized in solution with water for hydrolyzation generally. So, the reports about the nano-meter particles of alkaline-earth metalssulfides activated with Europium are found hardly any. The details as follows:1. Preparation, characterization and luminescent properties of CaS:Eu nano-phosphorThe materials: CaC^. (NH^SO^ EuCl3 and C are mixed. Then, the precursor is obtained by ultrasonic-coprecipitation method. Finally, the nano-particles of red persistent phosphor CaS: Eu is synthesized by sintering the precursor. The SEM image indicates the nano-particles are uniform, spheric and the diameter of the particles is under 50 nm. The excited spectrum of nanometer CaS: Eu is composed of two broad bands and the excited peak value locates at 270 nm and 545 nm respectively. In contrast to that of the phosphor synthesized by the solid reaction at high temperature, the excited spectrum of the nano-particles synthesized by sintering the precursor shifts to "blue section". The emission spectrum is a broad band and the emission peak value locates at 650 nm, which is ascribed to the transition of 4f7—?4f65d1 of Eu2+. The optimized condition of nanometer CaS:Eu synthesized is : 1000°C, 2h, Eu3+:Ca2+= 0. 0015 mol: 1 mol.In addition, Nano-particles of CaS: Eu are synthesized by microwave heating the precursor. The analysis results indicate the nano-particles are uniform, spheric and the diameter of the particles is under 50 nm. The excited peak value becomes less than that of the phosphor synthesized by sintering the precursor. As the microwave power is 750 w, the brightness of the nanometer CaS: Eu synthesized by microwave heating the precursor for 8 min is highest.2. Preparation, characterization and luminescent properties of SrS:Eu nano-phosphorNano-particles of SrS: Eu are synthesized by microwave heating the precursor obtained using the ultrasonic-coprecipitation method. The analysisresults indicate the nano-particles are uniform, spheric and the diameter of the particles is under 50 nm. The excited peak value becomes less. As the microwave power is 750 w, the brightness of the nanometer SrS: Eu synthesized by microwave heating the precursor for 12 min is highest.3. Preparation, characterization and luminescent properties of nano composite sunlight-conversion plastic flimNano-film was synthesized with nano-particles of CaS: Eu and PE. In contrast to the film of normal CaS:Eu, nano-film presents better scattered performance, physics performance and sunlight conversion performance.4. Preparation, characterization and luminescent properties of Cao.gZno.aTiCV. Pr, Na nano-phosphorMixing the materials: Pr(NO3)3 , Ca(NO3)2, Zn(NO3)2 ? NaNO3 , HOCH2CH2OH, critric acid and Ti(OC4H9)4 under certain condition, the precursor was obtained after a series of physical and chemical processes. Then, the nano-particles of red persistent phosphor Cao.gZno.2Ti03: Pr3+, Na+ was synthesized by sintering the precursor. The analysis results indicates that the uniform, spheric nano-particles of Cao.8Zn0.2Ti03: Pr3+, Na+ can be obtained when the precursor was sintered at 1000 °C for 5 h. The diameter of nano-particles is under 50 nm. In contrast to that of the phosphor synthesized by the solid reaction at high temperature, the excited spectrum of the nano-particles shifts to "blue section". The beginning brightness of the nano-particles is higher than that of the phosphor synthesized by the solid reaction at high temperature and the decay becomes faster.