Ultra-sensitive room temperature ammonia detection enabled by MEMS-based 0D/1D/2D PA₁₀Mo₂ nanocomposites

A 0D/1D/2D Au/PANI/MoS₂ hierarchical nanocomposite based on micro-electromechanical systems (MEMS) was successfully synthesized through in situ chemical oxidative polymerization. This composite overcomes the performance bottlenecks of single or dual-component combinations through a multi-dimensional synergy of "interface coordination-charge penetration-path optimization-stability enhancement." The built-in electric field generated by the p-n heterojunction formed between PANI and MoS₂ can drive the directional migration of carriers, thereby optimizing the carrier transport process. The synergy between Au nanoparticles and MoS₂ regulates the growth and distribution of PANI, enabling it to grow vertically on the MoS₂ surface and shorten the response and recovery time. At room temperature, the response and recovery times for 1 ppm ammonia are 69 s and 89 s, respectively, while those of pure PANI are 95 s and 156 s. Additionally, PANI resolves the problem of easy stacking between MoS₂ layers, increasing the proportion of active sites in the film from 12.82 to 45.87%. When the ammonia concentration is 1 ppm, the sensor can achieve a response value of 92.5%, with a theoretical minimum detection limit of 0.45 ppb. This research provides an innovative and efficient solution for ammonia detection at room temperature and shows significant potential in wearable electronic devices and human health monitoring.