Organic Thin-Film Transistors for Selective Hydrogen Peroxide and Organic Peroxide Vapor Detection

摘要

Direct selective detection of hydrogen peroxide and di-tert-butyl peroxide vapors was demonstrated using organic thin-film transistor (OTFT) threshold voltage shifts. Positive threshold voltage shifts are observed during peroxide vapor sensing for metal-phthalocyanine (MPc)- and naph-thalocyanine (Nc)-based OTFTs. The positive threshold voltage shift observed for peroxides is not evident with nonoxidizing analytes such as dimethyl methylphosphonate (DMMP) and water. MPc and Nc OTFT sensors operating at room temperature have distinct responses in mobility and threshold voltage to peroxide vapors. The mobility changes are reversible under dry air flow, whereas positive threshold voltage shifts are reversed by counter-dosing with a polar, electron-donating analyte. The peroxide-induced threshold voltage shifts suggest an accumulation of positive charge in the MPc/Nc film. The results are consistent with a dual-response mechanism in which the peroxide molecularly chemisorbs and subsequently catalytically decomposes, forming reactive products and increasing fixed positive charge.