UC San Diego

Detection of gas phase hydrogen peroxide (H₂O₂) has growing importance in the security and defenses industries. Hydrogen peroxide based explosives are increasingly popular with terrorists as they are simple to synthesize from common materials. Triacetone triperoxide, a common hydrogen peroxide based explosive, can be detected by its release of hydrogen peroxide vapor upon exposure to UV light. A selective peroxide vapor detection method is demonstrated utilizing metal phthalocyanine (MPc) thin film transistors (chemFETs) which obviated the need for a detection array. The selective detection of vapor phase H₂O₂ on a single sensor element is demonstrated by recording on-current, mobility, and threshold voltage in MPc chemFETs. Doses of H₂O₂ cause an irreversible threshold voltage shift not evident with the non-oxidizing common background analytes such water and di -methyl methylphosphonate (DMMP). Furthermore, the Vth shift responds linearly to the dose time for exposure times of 1, 5, and 20 minutes, which permits dosiometric sensing analysis. ChemFET vapor detection of di-tert-butyl peroxide is also reported with varying shifts in Vth based on the metal center of the phthalocyanine film. This analysis permits a novel approach to selective H₂O₂ detection which is fundamentally different and potentially more selective than prior H₂O₂ detection methods