Preparation And Luminescence Properties Of Rare Earth Doped Molybdenum/tungstate Nanocrystals

Lanthanide ions can exhibit sharp fluorescent emissions via intra-4f transitions because of unique and abundant energy level structures arising from 4fⁿ inner shell configurations.The controlled synthesis of nanocrystals with extremely small size,uniform shape,and relatively large specific surface areas is important for exploring the potential applications of RE ion doped nanocrystals.Here,we report a controlled synthesis of NaLa?MoO₄?₂?BaMoO₄,BaWO₄ and La₂Ti₂O₇ host materials.In addition,the luminescence properties and photocatalytic activity were studied in detail.The main contents in this thesis are as follows:?1?By using a straightforward hydrothermal strategy,we successfully prepared the rhombic NaLa?MoO₄?₂ nanocrystals through adjusting the raw material ratio and reaction temperature.NaLa?MoO₄?₂ is an excellent laser host material,by studing its corresponding luminous performance with Eu³⁺and Tb³⁺.?2?In this paper,we successfully synthesized string BaMoO₄:Ln³⁺?Ln=Eu,Tb,Er,and Gd?nanobeans by using a hydrothermal method.The photoluminescence properties of BaMoO₄:Ln³⁺were investigated in detail.Especially,the ²P_3/2?⁴I_11/2,²H_11/2?⁴I_15/2,and ⁴S_3/2?⁴I_15/2 transitions of Er³⁺ions in BaMoO₄:Er³⁺/Eu³⁺were observed for the first time.?3?We successfully synthesized the BaWO₄ nanocrystals by using a hydrothermal method,the photoluminescence properties of BaWO₄:Yb³⁺?20%?/Er³⁺were investigated in detail.The results show that BaWO₄ is an excellent laser host material.?4?Monoclinic phase La₂Ti₂O₇ and La₂Ti₂O₇:Eu³⁺nanocrystals were prepared by combining the hydrothermal method and calcination treatment.La₂Ti₂O₇ is an excellent fluorescent host material,by studing its corresponding luminous performance with Eu³⁺.In addition to the aforementioned photoluminescence properties,the La₂Ti₂O₇ and La₂Ti₂O₇:Eu³⁺nanocrystals can present photocatalytic activities for the degradation of RhB and 2,4-dichlorophenol.