Spectroscopic Characterization and Systematic Crystal-Field Modeling of Optically Active Rare Earth R3+ Ions in the Bismuth Germanate BiY1-x
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- 作者：C. Cascales ; C. Zaldo
- 刊名：Chemistry of Materials
- 出版年：2006
- 出版时间：August 8, 2006
- 年：2006
- 卷：18
- 期：16
- 页码：3742 - 3753
- 全文大小：355K
- 年卷期：v.18,no.16(August 8, 2006)
- ISSN：1520-5002
文摘
The synthesis conditions and structural characteristics of polycrystalline R-doped BiY1-xRxGeO5 orstoichiometric BiRGeO5 (R = trivalent rare earth Pr3+, Nd3+, Sm3+, Eu3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+,or Yb3+) germanate compounds are presented. The energy levels of each R3+ up to the absorption edgeof the germanate matrix have been established from 10 K optical absorption and photoluminescencespectra measurements. Detailed single-electron C2(Cs) Hamiltonians combining free-ion and crystal-field interactions have been used to model the above 4fN configurations. Very satisfactory correlationswere obtained between observed and the calculated energy levels, and corresponding tabulated data arereported. Systematic trends in the evolution of crystal-field parameters have been identified. The properestimation of phenomenological crystal-field parameters and crystal-field strengths at the R3+ site for thewhole Pr-Yb series is the first step in prospecting the possibilities of this germanate structure as a newsolid-state laser host. The observed medium-high (~660 cm-1) splitting for the 2F7/2 ground state ofYb3+ in BiYbGeO5 fulfills a prerequisite for an efficient Yb quasi-three-level laser operation. The possibilityof accepting large amounts of optically active R3+ ions and the intense Raman shifts observed at highfrequencies are other advantageous characteristics of the title host.