Effect of ion intercalation and electrochemisorption on nonlinear optical absorption of MoO₃: A comparative study of six different ions

Electrochemical modulation of nonlinear optical (NLO) absorption has recently garnered significant attention. In this work, we demonstrate the effective modulation of the third-order NLO absorption of layered molybdenum trioxide (MoO₃) by cation intercalation. Upon application of different negative voltages to samples in different electrolytes, we observe varying degrees of enhancement in MoO₃'s nonlinear absorption corresponding to different cations and different electrochemical processes. Cation intercalation of H⁺, Li⁺, Na⁺, K⁺, and Mg2⁺ is found to be more effective in enhancing the nonlinear absorption of MoO₃ than electrochemisorption of Al3⁺ cations. Notably, Li⁺ intercalation leads to the most significant performance improvement, with an enhancement of 11.6 times and a nonlinear absorption coefficient of - 79.88 ± 11.21cmGW-1. This improvement is ascribed to the increasing number of defect states in MoO₃ during ion intercalation, which strengthens its saturation absorption behavior. Our work provides valuable insights into the electrically controlled NLO performance of MoO₃ and can be applied to other similar materials.