Fabrication of Three-dimensional Porous Copper Phthalocyanine Films and Their Applications for NO2 Gas Sensors

In order to achieve high sensitivity in gas-sensors based on organic field-effect transistors (OFETs), the most crucial and direct approach to enhance their sensing performance and reduce response and recovery times was through appropriate modification or improvement of the organic semiconductor (OSCs) layer, such as altering its surface morphology or structure. The micro/nano structure of spin-coated copper phthalocyanine (CuPc) films was controlled by utilizing polyvinyl alcohol ordered nanofibers (PVA ONFs). The electrical and gas-sensitive properties of CuPc/PVA ONFs films were investigated and analyzed. The CuPc/PVA ONFs film transistors exhibited improved output and transfer characteristics when the CuPc solution concentration was 75 mg/mL, with a mobility (μ) of 6.90 × 10-4 cm2/Vs. Compared with the spin-coated CuPc film transistors, the mobility increased by 74.24%. The sensors demonstrated the relative response of 12,942 % to 20 ppm NO2 gas. Additionally, it showed the response time of 1.49 min and recovery time of 2.32 min. The response rate reached up to 90 %, while the sensitivity was measured at 611 %/ppm, and the limit of detection (LOD) stood at 0.2 ppm. The research presented in this paper advances the potential applications of phthalocyanine materials within the realm of flexible and 3D-printed sensing technologies.