Photoactivated conductive MOF thin film arrays on micro-LEDs for chemiresistive gas sensing.

Abstract

Electrically conductive metal-organic frameworks (cMOFs) are emerging as promising chemiresistors due to their diverse compositions, chemical properties, porosity, and room-temperature conductivity, enabling the design of energy-efficient devices. However, limited activation in this regime hinders sensitivity and reversibility. In this study, cMOF thin films are integrated onto a micro-LED (μLED) platform using a layer-by-layer method, enabling photoactivated gas sensing even at room-temperature. The systematic coating allows for precise tailoring of films (e.g., thickness and overlayer structures) based on the adsorption properties of each analyte (ethanol, trimethylamine, ammonia, nitrogen dioxide). The selected arrays are optimized by varying the wavelengths and intensities of μLED, enabling sensitive and reversible sensing through additional charge generation, while consuming ultra-low power (587 µW). Additionally, a deep learning algorithm achieves rapid gas recognition within tens of seconds, with 99.8% classification accuracy in concentration prediction. This work demonstrates the feasibility of the cMOF-μLED integrated sensor platform, paving the way for next-generation gas-sensing technologies.