N-terminalized titanium carbide MXene coupled with graphene oxide toward optimized temporal domain-dependent nonlinear absorption

A stepwise approach was implemented in this research to synthesize the covalent linkage between graphene oxide (GO) and MXene for the first time. The preparatory procedure involves the exchange of surface functional groups on MXene, followed by the covalent modification of N-terminalized MXene with GO, making a pioneering advancement in the domain of nonlinear optics. The resulting nanohybrids, labeled as f-MXene-GO, underwent fully comprehensive characterization by crystallographic, spectroscopic, and microscopic techniques. Z-scan measurements revealed that f-MXene-GO features an optimized nonlinear optical (NLO) response in both nanosecond (ns) regimes at 532 nm and femtosecond (fs) regimes at 800 nm across the visible and near-infrared spectra, surpassing its precursor and physically blended samples. The transmittance of f-MXene-GO gradually diminishes with increasing incident energy, displaying enhanced reverse saturable absorption (RSA) and optical limiting effects upon ns pulse excitation. Conversely, f-MXene-GO demonstrates promoted saturable absorption (SA) under fs laser illumination. The effective electron transfer process from MXene to the grafted GO, validated by theoretical calculations, stimulates superior NLO absorption. These findings not only elucidate the intricate relationship between the structure and the NLO response across wide spectral regions and time scales but also provide invaluable insights into the untapped potential of MXene-based materials for NLO applications.