Coupling porphyrin with MXene nanosheets: exploring non-covalent interactions and photophysical characteristics

A hybrid material was synthesized by coupling <i>meso</i>-(<i>p</i>-hydroxyphenyl)porphyrin (TPPH) with Ti₃C₂T_<i>x</i> MXene nanosheets <i>via</i> non-covalent interactions. The hybrid was characterized through UV-vis absorption, FTIR, Raman, steady-state and time-resolved fluorescence and absorption spectroscopy. The experimental data revealed significant electronic interactions between TPPH and MXene, supported by quantum chemical calculations. Formation of the ground-state TPPH/Ti₃C₂T_<i>x</i> complex was confirmed by a 40 nm red-shift in the porphyrin Soret absorption band. An analysis of steady-state and time-resolved emission experiments indicated that the observed quenching was solely due to a static mechanism. Femtosecond transient absorption spectroscopy demonstrated a rapid photoinduced electron transfer from the singlet excited state of TPPH to Ti₃C₂T_<i>x</i>, evidenced by the formation of a porphyrin radical cation. Additionally, the hybrid exhibited enhanced ambient stability compared to pristine MXene. These findings offer valuable insights into the photophysical properties of porphyrin-MXene hybrids, laying a strong foundation for their application in solar energy conversion technologies.