title: Efficient Deep Red Light-Sensing All-Polymer Phototransistors with p-type/n-type Conjugated Polymer Bulk Heterojunction Layers.
abstract: Here we demonstrate deep red light-sensing all-polymer phototransistors with bulk heterojunction layers of poly[4,8-bis[(2-ethylhexyl)-oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]-thiophenediyl] (PTB7) and poly[[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)] (P(NDI2OD-T2)). The device performances were investigated by varying the incident light intensity of the deep red light (675 nm), while the signal amplification capability was examined by changing the gate and drain voltages. The result showed that the present all-polymer phototransistors exhibited higher photoresponsivity (∼14 A/W) and better on/off photoswitching characteristics than the devices with the pristine polymers under illumination with the deep red light. The enhanced phototransistor performances were attributed to the well-aligned nanofiber-like morphology and nanocrystalline P(NDI2OD-T2) domains in the blend films, which are beneficial for charge separation and charge transport in the in-plane direction.
authors.affiliation: Organic Nanoelectronics Laboratory and KNU Institute for Nanophotonics Applications, 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 3PU, United Kingdom.
authors.forename: Sungho
authors.initials: S
authors.lastname: Nam
authors.affiliation: Organic Nanoelectronics Laboratory and KNU Institute for Nanophotonics Applications, 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 and KNU Institute for Nanophotonics Applications, Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University , Daegu 41566, Republic of Korea.
authors.forename: Hyemi
authors.initials: H
authors.lastname: Han
authors.affiliation: Organic Nanoelectronics Laboratory and KNU Institute for Nanophotonics Applications, 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: Department of Physics, Division of Mathematical, Physical and Life Sciences, University of Oxford , Oxford OX1 3PU, United Kingdom.|Department of Engineering Science, Division of Mathematical, Physical and Life Sciences, University of Oxford , Oxford OX1 3PJ, United Kingdom.
authors.forename: Donal D C
authors.initials: DDC
authors.lastname: Bradley
authors.affiliation: Organic Nanoelectronics Laboratory and KNU Institute for Nanophotonics Applications, Department of Chemical Engineering, School of Applied Chemical Engineering, Kyungpook National University , Daegu 41566, Republic of Korea.
authors.forename: Youngkyoo
authors.identifier: http://orcid.org/0000-0002-9391-2636
authors.initials: Y
authors.lastname: Kim
keywords: all-polymer phototransistor; deep red light-sensing; photoresponsivity; photoswitching; polymer/polymer bulk heterojunction layer