Single-Precursor Laser-Written Heterogeneous Oxide Array for Olfactory Sensing

Biomimetic olfactory systems utilizing cross-sensitive sensing arrays can detect and discriminate odors–a fundamental perceptual modality lacking in most intelligent systems. A primary implementation barrier lies in the inherent complexity of fabricating heterogeneous sensing arrays. Herein, a laser-programmable direct-writing strategy for single-step fabrication of heterogeneous transition metal oxide (TMO) arrays from a single precursor is reported. By precisely tuning laser parameters, in situ synthesis and continuous compositional modulation of multinary TMO heterostructures are achieved within millisecond timescales. Each fine-tuned TMO demonstrates distinct selectivity, and their combination generates signature patterns for different volatile organic compounds and complex odor mixtures. Phase analysis in combined with density functional theory (DFT) calculations, elucidates that phase transitions among competing oxide phases follow Boltzmann distributions governed by transient thermal gradient dynamics. DFT calculations of the electronic density of states further reveal the gas sensing mechanisms of laser-direct-written TMO heterostructures with varying surface phases. In addition to the new insights into laser-induced phase transformations in TMOs, this work establishes a highly efficient and scalable strategy for fabricating olfactory sensing arrays.