钨酸铅晶体中掺杂阳离子的计算机模拟

用缺陷化学方法讨论了Nd3 、Th4 、Sb5 掺杂PbWO4(PWO)中可能存在的杂质缺陷模型,用GULP软件计算了不同杂质缺陷的生成能.计算结果表明,Nd3 和Th4 将占据PWO晶体中VP2b-周围的Pb位,对VP2b-的电荷补偿抑制了PWO晶体中420 nm吸收带.Sb5 在高浓度掺杂时将占据PWO晶体中V2O 周围的W位,并由于占据W位所呈现的一价负电性补偿V2O 的正电性,使孤立的铅空位增多,引起350 nm吸收的减弱和420 nm吸收的增强.

Computer simulation of cations doped lead tungstate

The positions of the impurity ions of Nd3 ,Th4 ,Sb5 in PbWO4(PWO) crystal are simulated by computer technology.The corresponding defect clusters energy is calculated.The defect chemistry and the formation of the defect clusters are discussed.The mechanism of the doping effects of Nd3 ,Th4 ,Sb5 are studied.The calculation results show that the Nd3 and Th4 would occupy the Pb sites near V2-Pb,and restrict the 420 nm absorption band by compensating the electronegative charges of V2-Pb.When the PWO is doped with high concentration,the Sb5 would occupy the W sites near V2 O,make the V2-Pb capture two holes more easily to form the colour center of 420 nm absorption.The conclusions are detailedly discussed.