Electroluminescent Ag nanoparticles decorated carbon nanotubes–based device for room-temperature NH3sensing application

Abstract

Alternating-current electroluminescence (AC-EL) technologies have recently emerged as promising platforms for multifunctional optoelectronic devices. However, their application in gas sensing remains limited. Herein, we report a dual-function AC-EL device incorporating a silver nanoparticles–decorated carbon nanotubes (AgNPs–CNTs) sensing layer that enables simultaneous light emission and room-temperature ammonia (NH<inf>3</inf>) detection. The AgNPs–CNTs, consisting of CNTs with an average diameter of ∼16 nm uniformly decorated with AgNPs of ∼25 nm in diameter, significantly enhance charge transport and electric-field distribution, leading to a 1.6-fold increase in electroluminescent intensity after coating. Upon exposure to NH<inf>3</inf>, the device exhibits a clear and reversible decrease in optical luminance. The AgNPs-CNTs based AC-EL device demonstrates linear concentration-dependent sensing over the range of 100–1000 ppm (R² = 0.997), high sensitivity (∼0.026 ppm⁻¹), rapid response–recovery behavior, excellent device-to-device reproducibility, and strong selectivity against common volatile organic compounds and humidity. The sensing mechanism of the AgNPs-CNTs based AC-EL device is proposed via electron donation from NH<inf>3</inf> to the p-type CNTs, modulation of the AgNPs/CNTs metal–semiconductor junctions, and subsequent suppression of excitation processes within the ZnS:Cu,Cl phosphor layer. The results demonstrate a simple, low-cost, and scalable strategy for developing optical gas sensors based on AC-EL architectures. This work establishes AC-EL devices as a promising platform for next-generation visual gas indicators and low-power optoelectronic sensing systems suitable for environmental monitoring, smart packaging, and wearable electronics.