Semiconducting Properties of the Hybrid Film of Elastic Poly(styrene-b-butadiene-b-styrene) Block Copolymer and Semiconducting Poly(3-hexylthiophene) Nanofibers

Abstract

We investigated the electrical properties of a composite film loaded with semi-conductive poly(3-hexylthiophene) (P3HT) nanofibers dispersed in poly(styrene-b-butadiene-b-styrene) (SBS). This structure can be regarded as the hybrid of SBS matrix with elastic mechanical properties and P3HT nanofibers with semiconducting properties. The P3HT nanofibers were embedded in the fingerprint pattern of microphase-separated SBS, as observed by scanning force microscopy. Furthermore, the electrical conductivity and field-effect mobility of the composite films were evaluated. The field-effect mobility was estimated to be 6.96 × 10−3 cm2 V−1 s−1, which is consistent with the results of previous studies on P3HT nanofibers dispersed in an amorphous polymer matrix including poly(methyl methacrylate) and polystyrene, and we found that the P3HT nanofiber network was connected in the SBS bulk matrix. The film was stretchable; however, at elongation by two times, the nanofiber network could not follow the elongation of the SBS matrix, and the conductivity decreased drastically. The field-effect transistor of this film was operated by bending deformation with a radius of curvature of 1.75 cm, though we could not obtain an off-state and the device operated in a normally-on state.

Stretchable and Conductive Li-Complexed Poly(3-hexylthiophene) Nanofibrils/Elastomer Composites for Printed Electronic Skins

“…At room temperature, the color immediately changed to dark brown owing to the partial dissolution of the nanofibrils. However, the long nanofibrils are formed again during spin coating of the solution because of the self-seeded growth process. − Figure C briefly illustrates the fabrication process of the highly stretchable strain and pulse sensor arrays. SBS is highly soluble in diverse organic solvents including chlorobenzene, chloroform, m -xylene, and toluene.…”

“…These solvents are also commonly used for dissolving P3HT powders. Such good solubility and miscibility of SBS and P3HT in the organic solvents allow the reproducible fabrication of composite films via easy control of film morphologies and thickness . The viscous Li-P3HT/SBS solution was directly spin-coated onto Ag nanowire/Ecoflex electrodes covered with a PI stencil mask.…”

“…Such good solubility and miscibility of SBS and P3HT in the organic solvents allow the reproducible fabrication of composite films via easy control of film morphologies and thickness. 35 The viscous Li-P3HT/SBS solution was directly spin-coated onto Ag nanowire/Ecoflex electrodes covered with a PI stencil mask. The uniformly deposited active layers displayed high sensitivity to mechanical stimuli.…”

“…This can be attributed to the suppressed microphase separation of SBS domains by the growth of P3HT nanofibrils in thick films (thickness = 130 nm) compared to the previous study employing thinner SBS films (Figure S6B). 35 The white arrows in Figure 2C indicate nanofibrils embedded within the SBS layer. XPS analysis was performed to investigate the coordination between Li + and the lone-pair electrons of sulfur atoms.…”