Structural evolution and electronic properties of cerium doped germanium anionic nanocluster CeGen- (n=5-17): Theoretical investigation

The rare earth element doped germanium cluster represents a fundamental nanomaterial and exhibits potential in next-generation industrial electronic nanodevices and applied semiconductors. Herein, the cerium-doped germanium anionic nanocluster CeGen- (n = 5-17) has been comprehensively investigated by the double hybrid density functional theory of mPW2PLYP associated with the unbiased global searching technique of artificial bee colony algorithm. The cluster's growth pattern undergoes three stages: n = 5-9 with the replaced structure, n = 10-15 with the linked structure, and n >= 16 forming a Ce-encapsulated in Ge inner cage motif. The clusters' PES, IR, and Raman spectra were simulated, and their HOMO-LUMO gap, magnetism, charge transfer, and relative stability were predicted. These theoretical values can serve as a reference for future experiments to some extent. Moreover, the special D-2d symmetry cage geometry of CeGe16- leads to a higher stability and preferred energy gap, making it an ideal candidate for further studies on its aromaticity, UV-vis spectra, and chemical bonding characteristics. In summary, CeGe16- has excellent optical activity that can be potentially employed as a building block in the development of optoelectronic functional materials.