A low-symmetrical zinc phthalocyanine-based Langmuir-Blodgett thin films forNO₂ gas sensor applications

For many years effective detection of hazardous substances such as nitrogen oxides has remained a crucial task for environmental safety. In this article, we demonstrate high promising NO₂-sensitive Langmuir-Blodgett monolayer structures based on 2-((2'- hydroxymethyl)-benzyloxy)-9(10),16(17),23(24)-tri-/re/-butyl- substituted low symmetrical zinc phthalocyanine complex bearing hydroxyl group on the periphery (compound 1). Amphiphilic arrangement of macrocycles was demonstrated to eliminate disordered molecular aggregation, resulting in a marked NO₂ gas sensing effect under real atmospheric conditions. The optical response of monolayers was at room temperature, with the significant spectral changes being caused by the specific charge transfer process in phthalocyanine n-conjugated electronic system. (paper)