title: Broadband pH-Sensing Organic Transistors with Polymeric Sensing Layers Featuring Liquid Crystal Microdomains Encapsulated by Di-Block Copolymer Chains.
abstract: We report broadband pH-sensing organic field-effect transistors (OFETs) with the polymer-dispersed liquid crystal (PDLC) sensing layers. The PDLC layers are prepared by spin-coating using ethanol solutions containing 4-cyano-4'-pentyl-biphenyl (5CB) and a diblock copolymer (PAA-b-PCBOA) that consists of LC-philic block [poly(4-cyano-biphenyl-4-oxyundecyl acrylate) (PCBOA)] and acrylic acid block [poly(acrylic acid) (PAA)]. The spin-coated sensing layers feature of 5CB microdomains (<5 μm) encapsulated by the PAA-b-PCBOA polymer chains. The resulting LC-integrated-OFETs (PDLC-i-OFETs) can detect precisely and reproducibly a wide range of pH with only small amounts (10-40 μL) of analyte solutions in both static and dynamic perfusion modes. The positive drain current change is measured for acidic solutions (pH < 7), whereas basic solutions (pH > 7) result in the negative change of drain current. The drain current trend in the present PDLC-i-OFET devices is explained by the shrinking-expanding mechanism of the PAA chains in the diblock copolymer layers.
authors.affiliation: Organic Nanoelectronics Laboratory, Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University , Daegu 41566, Republic of Korea.
authors.forename: Jooyeok
authors.initials: J
authors.lastname: Seo
authors.affiliation: Organic Nanoelectronics Laboratory, Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University , Daegu 41566, Republic of Korea.
authors.forename: Myeonghun
authors.initials: M
authors.lastname: Song
authors.affiliation: Organic Nanoelectronics Laboratory, Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University , Daegu 41566, Republic of Korea.
authors.forename: Jaehoon
authors.initials: J
authors.lastname: Jeong
authors.affiliation: Organic Nanoelectronics Laboratory, Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University , Daegu 41566, Republic of Korea.|Department of Physics, Division of Mathematical, Physical and Life Sciences, University of Oxford , Oxford OX1 3PD, United Kingdom.
authors.forename: Sungho
authors.initials: S
authors.lastname: Nam
authors.affiliation: Department of Polymer Science and Engineering and Graduate School of Applied Chemical Engineering, Kyungpook National University , Daegu 41566, Republic of Korea.
authors.forename: Inseok
authors.initials: I
authors.lastname: Heo
authors.affiliation: Department of Polymer Science and Engineering and Graduate School of Applied Chemical Engineering, Kyungpook National University , Daegu 41566, Republic of Korea.
authors.forename: Soo-Young
authors.initials: SY
authors.lastname: Park
authors.affiliation: Department of Polymer Science and Engineering and Graduate School of Applied Chemical Engineering, Kyungpook National University , Daegu 41566, Republic of Korea.
authors.forename: Inn-Kyu
authors.initials: IK
authors.lastname: Kang
authors.affiliation: School of Materials Science and Engineering, Kyungpook National University , Daegu 41566, Republic of Korea.
authors.forename: Joon-Hyung
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Organic Nanoelectronics Laboratory, Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University , Daegu 41566, Republic of Korea.|Priority Research Center, Research Institute of Advanced Energy Technology, Kyungpook National University , Daegu 41566, Republic of Korea.
authors.forename: Hwajeong
authors.initials: H
authors.lastname: Kim
authors.affiliation: Organic Nanoelectronics Laboratory, Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University , Daegu 41566, Republic of Korea.
authors.forename: Youngkyoo
authors.initials: Y
authors.lastname: Kim
keywords: diblock copolymer; liquid crystal; organic field-effect transistor; pH sensor; perfusion