锗酸锌锰荧光体发光学与荧光瞬态衰减研究

制备一系列锗酸锌锰荧光体,并探讨其发光特性、瞬态荧光衰减与色度值与所掺杂锰离子含量之间的相互关系.本系列荧光体锰离子发射峰波长,随Mn²⁺含量由0增加0.05,由527nm红移至534nm.实验表明这可能与Mn²⁺所占据的四面体格位,遭扭曲而导致晶场强度变弱有关.本系列荧光体的CIE色度坐标值,则随所掺杂Mn²⁺含量,仅有微小改变.锗酸锌锰荧光体瞬态荧光衰减的研究结果表明:锗酸锌基质的衰减生命期在纳秒范围;随Mn²⁺掺杂量增加,在毫秒范围的锰离子荧光衰减生命期逐渐缩短.此现象可能与Mn²⁺-Mn²⁺离子对中,Mn²⁺的自旋交换相互作用有密切关系.

Luminescence and Time-Resolved Fluorescence Decay of Mn2+ -activated Zn2 GeO4 Phosphors under Ultraviolet Excitation

We have investigated the synthesis, luminescence and time-resolved fluorescence decay spectra for Zn2 GeO4: xMn phosphors doped with different contents of Mn2 + as an activator. The microstructure of Zn2 GeO4: xMn samples is highly dependent on synthetic conditions. The observed red shift in λem from 527 nm to 534 nm with increasing Mn2+ content has been investigated and rationalized by the presence of a weak crystal field due to the substitution of Zn2+ by Mn2+ , which leads to a distorted tetrahedral lattice site. The CIE chromaticity coordinates were found to shift slightly with variation of doped Mn2+ content. Time-resolved fluorescence decay curves of Zn2GeO4:xMn have also been investigated. Interestingly, the shortening of fluorescence decay lifetime observed in Zn2 GeO4:xMn phosphors with increasing Mn2+ dopant concentration has been rationalized by the alteration of transition probability as a consequence of magnetic interaction between Mn2 + -Mn2 + pairs in the host lattice.