Automation assisted systematic investigation on ZIF photonic crystals: From microscopic mechanism to the detection of organophosphorus compounds

Metal-organic framework materials exhibit significant advantages in the field of harmful gas adsorption by virtue of their large pore size and high specific surface area. The construction of photonic crystals using zeolitic imidazolate framework-8 (ZIF-8) particles as assembly units can enhance the signal transduction ability, and their polyhedral morphology further expands the ordered arrangement of photonic crystals. In this study, we focus on the optimization of the assembly conditions, response properties, and mechanism of action of ZIF-8 particles, and combine with an automated photonic crystal preparation platform to realize the rapid screening of assembly parameters. The optimized ZIF-8 photonic crystal arrays exhibit selective naked-eye recognition of organophosphorus compounds: It is experimentally confirmed that organophosphorus compounds induce particle size changes through adsorption–surface interactions, which in turn modulate the photonic bandgap widths and lead to the quenching or enhancement of reflectance spectra at specific wavelengths, whereas small-molecule alcohols trigger the spectral quenching of only a single wavelength due to the adsorption-induced particle swelling. The Python-based automated control platform further enables scalable morphology tuning and successfully prepares colored microspheres with tunable photonic properties. This study reveals the ligand-mediated assembly mechanism of metal-organic framework photonic crystals and provides a theoretical basis for the design of metal-organic framework photonic crystals.