Fluorescent Chemo-sensors Based on “Dually Smart” Optical Micro/nano-waveguides Lithographically Fabricated with AIE Composite Resins

Novel high-performance non-label fluoro-sensing micro/nano-optics requires lithographically fabricable stimuli-fluorescence energy transductive materials well-tailored in molecular level, towards superior processibility, stability, sensitivity, on-chip integration and and portability, and real-time and in-situ analysis. Here, aggregation-induced-emission fluorophores with oxetane groups (AIEoxes) and their covalently co-crosslinkable epoxy composites are customized for the fabrication of micro/nano-devices via single/multi-photon lithographies. The oxetane modification increase AIEoxe’s miscibility in epoxy matrix (the doping ratio up to 10 wt%), and consequently, improved as-formed devices’ quality, stability, and fluorescent intensity and sensitivity. The multi-color-AIEoxe polymeric micro/nano-devices allow fluorescence-resonance-energy-transfer among AIEoxes, which enables sensitive and specifically recognizable spectral detection. With the micro/nano-waveguide configuration, solvent-responsive AIE fluorescence and evanescent-field/refractive-index sensing enhance the AIE-fluorescent detection of trace organic solvents in aqueous solutions (detection limit, ~0.004% v/v, tetrahydrofuran/water) and their facile integration in functional micro/nano-systems like optofluidics.