The The Sral <sub> 2 </ Sub> O <sub> 4 </ Sub>: Eu Of <sup> 2 + </ Sup>, Dy By <sup> 3 + </ Sup> Rare Earth Storing Materials Preparation And Properties Of

In this thesis, SrAl2O4:Eu2 + ,Dy3 + long afterglow photoluminescence materials were prepared by coprecipitation synthesis. TG-DTA, XRD, SEM, and luminescence spectrum analyzer were used to analyse and measure SrAl2O4:Eu2+,Dy3+ phase transition process, microstructures, surface morphology, excitation and emission spectrums, afterglow decay performances. The results show that the samples sintered at 1100℃are all monoclinic SrAl2O4 and the grain sizes are about 10~100μm. The excitation and emission spectrums of samples are both broad-band spectrums. The peak of the emission spectra is at 520 nm. The samples sintered at 1100℃for 2h in reduction atmosphere show optimal luminescent properties. The initial luminosity and the decay times of the samples are larger than 8000mcd/m2 and 8 hours respectively. Adding proper H3BO3 in the samples can decrease sintering temperature greatly and increase the content of SrAl2O4 matrix and improve phosphor performances. It is discovered that the emission intensity of phosphors increases firstly then decreases with the content of Eu2+ increasing. The quenching concentration of Eu2+ is about 0.75mol%. It is proved that the fluorescent decay process includes fast decay and consequently slow decay process due to the two different existent trapping levels. Dy3+ can play an important role in the process of decay. With the content of Dy3+ increasing, the depth of trap level also increases. With the sample grain sizes decreasing, the initial luminosity of the samples are decreased, but increased for decay speed. Red shift of excitation and emission spectrums are observed.