PdPc-PANI Hybrid Organic Semiconductor Film And The Gas Sensitive Mechanism Study

Along with the increasingly regard on environment protection, the study of poison gas sensor has magnitude significance. At present, the main methods adopted are inorganic way, it exists such problems as technique complex,high cost,low precision etc. Due to the low cost,simple film forming craft,compatible with other technique easily,work in mormal temperature, organic semiconductor has become the hotspot of study. Polyanilin (PANI) and metal phthalocyanine are two typical representations of it.This paper used cyclostyle methods to synthesize PdPc, and PANI doped with HClO₄ was also composed. The related characterization was carried out. Adopt micro-machining technique and mechanical mask, the Pt flat electrode which has heating resistor on its back was fabricated. This two organic semiconductor materials were mixed with each other on different ratios (PANI)_x(PdPc)_1-x(0≤x≤1) in order to relize hybrid and form film on the electrode by coating film craft and evaporated film craft in order to make gas sensor. Through gas sensitive testing in NO₂,SO₂,NO,Cl₂ with the density of 0.01﹪, the mixing material which has best sensitive ability was expected to be acquired. The result indicates that the compound film with x=1/6 has well sensitivity to different gas.The coating film and evaporated film were both characterized by SEM. From the two sides of the micro appearance and molecular structure, the sensitive mechanism was analyzed. The coating films of PdPc and PANI both have loose structure and reticular air hole; the evaporated film of PdPc appears spheric crystal grains with partly embed with each other. PANI film appears acicular crystal grains uniform distribution. Both have air hole. The presence of the air hole is propitious to the gas's adsoption and desorption. The coating film has bad order state, thick film, long response time but high sensitivity; the evaporated film has uniform distribution, thin film, low sensitivity but short response time. Furthermore, the effects of different factors such as the structure of the device and the detecting mode etc. on the sensitivity were also discussed. The foreground of the coming development was prospected.The experiment data show the feasibility of the principle and the craft, but its stability and sensitive mechanism still need to be further discussed. The compound film with other mixing ratios also could gain better sensitivity through the approach such as changing craft etc. Furthermore, the other characteristics such as selectivity of the compound film which has better sensitivity also need deep study. Detecting gas through sensor array using the hybrid material with different ratios is expected to realize.