Ultra-Sensitive Room-Temperature Ammonia Detection Enabled by MEMS-Based 0D/1D/2D PA10Mo2 Nanocomposites

In this study, a 0D/1D/2D Au/Polyaniline/MoS₂ (PA ₁₀ Mo ₂ ) hierarchical nanocomposite based on microelectromechanical systems (MEMS) was successfully synthesized via in situ chemical oxidative polymerization. The 0D, 1D, and 2D materials in the composite form a three-dimensional transport network; the surfaces of MoS₂, PANI, and Au promote gas diffusion through unsaturated bonds, polar groups, and high surface energy, respectively. The sensor fabricated from this composite exhibits response and recovery times of 69 seconds and 89 seconds, respectively, at room temperature for 1 ppm of ammonia, whereas those of pure PANI are 95 seconds and 156 seconds, respectively. Additionally, gold nanoparticles regulate the growth and distribution of PANI and MoS₂, increasing the active sites in the film from 12.82% to 45.87%. Moreover, the built-in electric field of the p-n heterojunction formed between PANI and MoS₂ drives the directional movement of carriers, optimizing carrier transport. When the ammonia concentration is 1 ppm, the sensor can achieve a response of 92.5%, and its theoretical minimum detection limit is 0.45 ppb. This work presents an innovative and efficient solution for ammonia sensing at room temperature, demonstrating significant potential in the fields of wearable electronic devices and human health monitoring.