Electrodeposition of PTCTA/ZnO Composite Films for Acetic Acid Vapor Detection at Room Temperature

Metal oxide semiconductor sensors based on zinc oxide (ZnO) and its composites are found to be very sensitive in detecting acetic acid vapor. However, its operating temperatures usually exceed 200 °C. In this work, an environmentally friendly and controllable electrochemical approach for constructing poly(4,4',4″-Tris(carbazol-9-yl)-triphenylamine) (PTCTA) and ZnO composite films was successfully obtained for acetic acid sensing at room temperature. The conjugated microporous polymer (CMP) films of PTCTA were synthesized via an electropolymerization (EP) method using 4,4',4″-Tris(carbazol-9-yl)-triphenylamine (TCTA) molecule as a precursor. Subsequently, ZnO was deposited in situ to fabricate homogeneous PTCTA/ZnO composite films. The resulting PTCTA/ZnO composite films achieved a response value of 2.42 for 200 ppm acetic acid vapor at room temperature, which was significantly outperforming standalone PTCTA or ZnO films. This enhanced sensing capability was attributed to the porous structure, the synergistic effects of the p-n heterojunction at the PTCTA/ZnO interface and the oxygen adsorption/desorption occurring on the ZnO surface. What's more, PTCTA/ZnO composite films demonstrated structural stability and flexibility. The results suggested that the developed novel PTCTA/ZnO composite films showed great potential for acetic acid determination.