Facile Synthesis of Fullerene‐Like Polyoxotitanium Clusters and Their Metal‐Doped Derivatives With Nonlinear Optical Properties

ABSTRACT We report a facile solvothermal synthesis of a fullerene‐like polyoxotitanium cluster ( TOF‐1 ) and its metal‐doped derivatives, TOF‐1‐Cu and TOF‐1‐Mn . Solid‐state UV–Vis diffuse reflectance spectroscopy shows that metal incorporation effectively narrows the optical band gap from 3.67 eV for TOF‐1 to 3.01 and 3.33 eV for TOF‐1‐Cu and TOF‐1‐Mn , respectively. Open‐aperture Z‐scan measurements demonstrate that TOF‐1 exhibits typical reverse saturation absorption behavior, with the minimum normalized transmittance decreasing as the incident laser pulse energy increases. Notably, TOF‐1‐Cu displays enhanced nonlinear optical performance compared with the parent cluster and shows a clear concentration‐dependent nonlinear optical response. These results indicate that fullerene‐like polyoxotitanium clusters and their metal‐doped derivatives constitute a promising inorganic–organic hybrid platform for nonlinear optical applications.