Laser constructed vacancy-rich TiO2-x/Ti microfiber via enhanced interfacial charge transfer for operando extraction-SERS sensing

Abstract

Semiconductor-molecule surface-enhanced Raman scattering (SERS), especially the stronger interfacial charge transfer process (ICTP), represents a frontier in the field of SERS with spectral reproducibility and unparalleled selectivity. Herein, through a laser microfabrication method in situ, the free-standing, super hydrophilic and vacancy-rich TiO2-x/Ti is successfully synthesized. Using blue TiOx/Ti (B-TiOx/Ti) as pre-concentrated substrate, a nanomolar-level limit of detection of 12 nmol/L at 1385 cm–1, is confirmed using crystal violet (CV) bacteriostat as a model under 532 nm excitation. Furthermore, the results demonstrate that the SERS enhancement mechanism is via the moderate adulteration of oxygen vacancy, which leads to a narrow value of band gap and increases the ICTP of substrate to molecules. Using a hand-held extractor assembled with B-TiOx/Ti microfiber, the operando analysis of mixtures distributed information excited in different parts of Asian carp is facilely achieved. This work guides the controlled synthesis of vacancy-rich TiO2-x/Ti nanostructure and its application in ultrasensitive extraction-SERS detection. It also provides the direction for the rapid and operando transmission of biological information with temporal and spatial concentration distribution in human tissues by highly sensitized materials.