Bioinspired Hierarchical Silica Nanoarchitecture for VOCs Discrimination through Confined-Space Optical Modulation

Abstract

Abstract Optical discrimination of volatile organic compounds (VOCs) commonly relies on chemically active materials or multisensor arrays, making stable signal transduction and structural integration challenging. Here, we report a bioinspired hierarchical silica nanoarchitecture replicated from Morpho butterfly wing scales for photoreflectance discrimination of six organic vapors. The architecture preserves multilevel ridges, lamellae, papillae, and interconnected gaps spanning the nanoscale to microscale. Coupled with a fiber-optic readout, it generates analyte-dependent reflectance profiles across 380–1045 nm, with a maximum reflectance change of 80%, enabling differentiation among the tested VOCs. The silica replica shows a blank-to-recovery reflectance deviation below 1% at 996 nm under nitrogen-cycling tests, confirming baseline stability of the readout. Wave-optical simulations support a confined-space optical modulation mechanism, in which vapor filling within hierarchical gaps changes the effective refractive index and reshapes the photoreflectance spectra. This work establishes a structure-encoded route to VOCs discrimination using a single inorganic photonic architecture.