Molecular understanding of a π-conjugated polymer/solid-state ionic liquid complex as a highly sensitive and selective gas sensor. Issue 43 (26th August 2020)

• Record Type: Journal Article
• Authors: Stewart, Katherine; Limbu, Saurav; Nightingale, James; Pagano, Katia; Park, Byoungwook; Hong, Soonil; Lee, Kwanghee; Kwon, Sooncheol; Kim, Ji-Seon
• Is Part Of: Journal of materials chemistry. Volume 8:Issue 43(2020)
• Page Start: 15268
• Page End: 15276
• Publication Date: 2020-08-26
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0tc03093g
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Electric-field driven chemical doping modulation in a solution-processed organic semiconductor and solid-state ionic liquid blend in response to volatile organic compounds provides an exciting opportunity to facilitate low-power chemical gas sensors. Abstract : Electric-field driven chemical doping modulation in a blend of solution-processed organic semiconductors (OSCs) and solid-state ionic liquids (SSILs) in response to volatile organic compounds (VOCs) provides a new exciting opportunity to facilitate printable and low-power chemical gas sensors (chemiresistors). In order to fully exploit this opportunity, a fundamental understanding of the molecular-level interactions among the OSCs, SSILs, and VOC components during the device operation is urgently needed. Herein, we demonstrate a highly sensitive and selective VOC gas sensor using π-conjugated polymer (here, P3HT as a model homopolymer) and SSIL blends. A newly developed SSIL forms a semi-crystalline solid at room temperature. P3HT with high molecular weight and regioregularity allows an extremely well-interconnected network in blends desirable for efficient charge transport. In P3HT:SSIL blends, we identify electric-field driven strong chemical interactions between π-CP and SSIL to tune the electrical conductivity of the π-CP. The enlarged interfacial areas in blends and the solid-state nature of the SSIL ensure highly tunable electrochemical interactions between them, efficiently modulating the electrical conductivity of the π-CP further upon exposure to different polar and non-polar VOCs. Our results demonstrate the π-conjugated polymer/SSIL complex as a new highly sensitive and selective gas sensor and provide a key scientific understanding of its molecular-level operational mechanism critical for developing molecular sensors towards next generation noninvasive diagnostics.