Polyaniline @ porous nanosphere SnO_2/Zn_2SnO_4 nanohybrid for selective room temperature flexible NH_3 sensor

摘要

A simple and cheap flexible gas sensor utilizing polyaniline @ porous nanosphere SnO_2/Zn_2SnO_4 nanohybrid (PZN) was assembled on a polyethylene terephthalate (PET) film free of interdigital electrode by in-situ chemical oxidation polymerization technique for rapid and selective detection of NH_3 at room temperature. The structure, morphology and composition of as-prepared sample was characterized roundly through XRD, FESEM, TEM, Raman, UV-vis and XPS, respectively. The effect of different mole amount of porous nanosphere SnO_2/Zn_2SnO_4 composite on NH_3 sensing response was appraised and the results indicated that PZN flexible sensor with a 10 mol% porous nanosphere SnO_2/Zn_2SnO_4 (PZN 10) to 100 ppm NH_3 exhibited response signal of 20.4, which is 2.6 times higher than that of pristine polyaniline (7.8) at room temperature. Furthermore, PZN 10 flexible sensor possessed low detection limit of 500 ppb of NH_3 in conjunction with good reproducibility, bending and robustness properties at room temperature. The enhanced NH_3 sensing properties can be attributed to the morphology structure and p-n heterojunction between polyaniline and porous nanosphere SnO_2/Zn_2SnO_4, and the underlying sensing mechanism was also further analyzed and verified using impedance spectroscopy.