0D MXene quantum dots/2D MXene derived metal–organic frameworks for enhanced nonlinear optical absorption across spectral and temporal regimes

Abstract

Metal–organic frameworks (MOFs) with π-electronic conjugated systems have garnered considerable attention, enabling third-order nonlinear optics. However, their nonlinear optical (NLO) properties pose challenges, including photogenerated carrier formation and low charge separation, which require urgent improvement. In this study, zero-dimensional Ti₃C₂ MXene quantum dots (Ti₃C₂ QD) and two-dimensional V₂C MXene derived porphyrinic MOFs (V₂C PMOF) are assembled into the heterostructure, denoted as Ti₃C₂ QD/V₂C PMOF, which is fully characterized by crystallographic, spectroscopic, and microscopic methods. It is worth noting that the parental features are easily inherited from the hard template, thus tailoring MOFs with controlled dimensional growth. The Ti₃C₂ QD/V₂C PMOF heterostructure shows optimized reverse saturable absorption (RSA) compared to individual components, under irradiation with both nanosecond (ns) pulses at 532 nm and femtosecond (fs) pulses at 800 nm. The enhancement of the NLO response is mainly attributed to the exceptional interfacial electron transfer capabilities, corroborated by steady-state photoluminescence, X-ray photoelectron spectroscopy, and theoretical calculations. These discoveries not only provide invaluable insights into the undeveloped vanadium-based MOF for future practical NLO applications but also establish a reference for the development of MOF-based materials via the guest–host strategy.