Twistable and tailorable Cu-doped SnO2@PANI textile for wearable ammonia sensing

Abstract

Herein, a twistable and tailorable NH3 sensor utilizing hollow porous Cu-doped SnO2@PANI (PCS) composite was assembled on a flexible non-woven fabric substrate by in-situ polymerization technique and its gas sensing performance was tested at room temperature (∼25 °C). The results indicated that the well-designed PCS sensor to 50 ppm NH3 exhibited six times higher response (25.4) than the pristine PANI sensor (4.5). The PCS flexible sensor still possessed a response (1.53) for 10 ppb NH3, and the detection limit could reach 5.2 ppb for NH3. Meanwhile, the PCS flexible sensor demonstrated excellent flexibility with response decreases of only 1.97 % after 1000 times bending (120°), and 2.11 % after 100 times folding (150°) and long-term stability through 42 days of monitoring (maintaining 98.4 % response). Furthermore, the PCS sensor displayed insensitivity to relative humidity (20 % − 75 % RH), and the low sensing temperature could reach − 15 °C. The enhanced sensing performance of the PCS sensor was attributed to the synergistic effect of the vital role of abundant oxygen vacancy and − OH groups, as well as the hollow porous interconnected structure and the p-n heterojunction between Cu-doped SnO2 and PANI. This work provides more opportunities to design smart wearable devices for detecting ppb-level NH3 at room temperature.