Chemical surface treatment with toluene to enhances sensitivity of NO2 gas sensor based on CuPcTs/Alq3 thin films

Abstract

The nitrogen dioxide (NO2) gas sensor based on the blend of copper phthalocyanine-tetrasulfonic acid tetrasodium/tris-(8-hydroxyquinoline)aluminum (CuPcTs/Alq3) thin films was fabricated. The effect of chemical surface treatment with toluene on the structural, surface morphology and device sensitivity has been examined. The X-ray diffraction (XRD) patterns for as-deposited and chemically treated with toluenefilms exhibit a broad hump peak at 2q-24. The atomic force microscopy (AFM) measurements show that the average particle diameter decreases with immersing time. The needle like shapes can be seen from scanning electron microscopy (SEM) images forfilms treated at 60 min immersing time with toluene. Gas sensor characterizations demonstrate that all samples have superior NO2 gas sensitivity at 373 K operating temperature. The increase of sensitivity with increasing chemical treatment time up to 60 min was observed. Allfilms show a stable and repeatable response patterns