Geometrical Evolution Pattern and Spectroscopic Properties of Terbium-Doped Germanium Anionic TbGen (n = 6–17) Nanoclusters: From Tb-Lined to Tb-Encapsulated Structures

Developing advanced materials with enhanced performance through the doping of nanoclusters is a promising strategy. However, there remains an insufficient understanding of the specific effects induced by such doped nanoclusters, particularly regarding the structural evolution pattern after doping with rare-earth elements and their impact on performance. To solve this problem, we used first-principles calculation to study the structural evolution pattern and spectroscopic properties of anionic TbGe<i>_n</i> (<i>n</i> = 6-17) nanoclusters through the ABCluster global search technique coupled with the mPW2PLYP double-hybrid density functional theory. The results revealed that the geometrical evolution pattern is from the typical Tb-linked structures (for <i>n</i> = 10-13, in which Tb acts as a linker connecting two germanium sub-clusters) to Tb-centered cage configurations (for <i>n</i> = 14-17). The simulated photoelectron spectroscopy of anionic TbGe₁₆ agrees well with its experimental counterpart. Furthermore, we calculated properties such as infrared spectroscopy, Raman spectroscopy, ultraviolet-visible (UV-vis) spectra, magnetism, charge transfer, the HOMO-LUMO gap, and relative stability. The results suggest that TbGe₁₂^- and TbGe₁₆^- clusters, with their remarkable stability and tunable photothermal properties, can serve as ideal building blocks for developing novel functional nanomaterials. These clusters demonstrate promising applications in solar photothermal conversion, photoelectric conversion, and infrared imaging technologies through their distinct one- and three-dimensional architectures, respectively.