Controllably fabricated single microwires from Pd-WO_3·xH_2O nanoparticles by femtosecond laser for faster response ammonia sensors at room temperature

摘要

Microanoscale gas sensors attracted more attention because of their potential application in the emerging areas such as electronic capsules, wearable devices, and microdrone detectors. However, it is still a challenge to achieve microanoscale sensors with controllable processing parameters of active components and fast response and recovery capability. Here, a flexible and high precision femtosecond laser direct-writing technology is selected to print various semiconductor metal oxides nanoparticles into microscale designable patterns with mask-free. And by using Pd-doped WO_3·xH_2O nanoparticles we have fabricated single Pd-WO_3·xH_2O microwire (SPWM) as gas sensors, which represented high sensitivity, faster response and recovery. Especially, for ammonia gas sensing the SPWM with pre-designed lengths can possess ultrafast response with response/recovery time of 1.4/3.3 s in 50 ppm NH_3, or low limit-of-detection of 1 ppm at room temperature. This kind of micro-scale gas sensor is expected to be applied to human health monitoring, environmental air detection and other integrated intelligent devices.