Single-Crystal-like Structure of Poly(9,9-dioctylfluorene) Thin Films Evaluated by Synchrotron-Sourced Grazing-Incidence X-ray Diffraction

Misaki, Masahiro; Nagamatsu, Shuichi; Chikamatsu, Masayuki; Yoshida, Yūji; Azumi, Reiko; Tanigaki, Nobutaka; Ueda, Y.; Yase, Kiyoshi

doi:10.1295/polymj.pj2007063

Cited by 9 publications

(11 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The half-width of the distribution of the (110) diffraction plane was estimated to be 4°, which means that the molecular chains are excellently oriented along the friction direction in the film. This distribution of the PT films is comparable to that of PTFE films (about 3°) [ 40 ] and poly(9, 9′-dioctylfluorene) films (about 2–3°) [ 57 ].…”

Section: Resultssupporting

confidence: 54%

Oriented Thin Films of Insoluble Polythiophene Prepared by the Friction Transfer Technique

et al. 2021

Self Cite

View full text Add to dashboard Cite

A thin film of unsubstituted polythiophene (PT), an insoluble conjugated polymer, with molecular chains uniaxially oriented in plane was prepared by the friction transfer method. The structure of highly oriented thin films of PT was investigated using grazing-incidence X-ray diffraction (GIXD), ultraviolet–visible (UV–vis) spectroscopy, and infrared (IR) spectroscopy. The polarized UV–vis and IR spectra and GIXD measurements showed the PT molecular chains were well aligned in parallel to the friction direction. The GIXD studies clarified that the polymer backbones were aligned with very narrow distribution, such that the half-width was about 4 degrees. The degree of orientation of the PT friction-transferred film was higher compared with those of regioregular poly(3-alkylthiophene)s. Moreover, the GIXD results show a preferred orientation where the a-axis is perpendicular to the substrate plane.

show abstract

Section: Resultssupporting

confidence: 54%

Oriented Thin Films of Insoluble Polythiophene Prepared by the Friction Transfer Technique

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Orientation methods for CPs are generally categorized by the physical state, in which they were processed such as by processing in solution state or in solid state . Solution processing made the device fabrication possible at low cost and low temperature; nonetheless, there are some limitations such as a need for good solubility of the CPs, surface wettability, and, in some techniques, pre-aggregation in solution is essential for orientation. , At the same time, a need for halogenated organic solvents for film fabrication may also create serious health and environmental hazards during large-scale production. , Friction transfer is a solvent-free processing method to orient CPs and is effectively utilized to overcome these issues. − There are reports on the high optical anisotropy of such thin films and their impact on controlling the anisotropic charge transport. − …”

Section: Introductionmentioning

confidence: 99%

Investigation and Control of Charge Transport Anisotropy in Highly Oriented Friction-Transferred Polythiophene Thin Films

Kumari

Pandey

Nagamatsu

et al. 2020

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

Highly oriented thin films of poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno [3,2-b]thiophene] (PBTTT) were prepared by friction-transfer technique followed by their characterization using polarized absorption spectroscopy, angle-dependent polarized Raman spectroscopy, and X-ray diffraction (XRD) techniques. Orientation in high-molecular-weight (M W ) polymers is hampered by chain folding or entanglements, which limit their macromolecular orientation. Interestingly, utilizing high-molecular-weight PBTTT (M W > 50 kDa) and friction-transfer technique, successful fabrication of highly oriented thin films with very high dichroic ratio (∼30) was demonstrated. The role of the substrate's surface energy and its impact on the field-effect mobility (μ) of the oriented thin films were comprehensively investigated. The influence of annealing the thin films as prepared on the bare and self-assembled monolayer (SAM)-treated SiO 2 surfaces exhibiting differential trends of μ was systematically investigated. This was explained by partial and complete conformational transformation of macromolecules on bare and SAM-treated SiO 2 surfaces, respectively, after annealing them beyond liquid crystalline phase transition temperature, as revealed by in-plane and out-of-plane XRD results. On bare SiO 2 , optimum μ up to 0.03 cm 2 V −1 s −1 along the backbone orientation was obtained for the thin films annealed to 120 °C; whereas, it reached up to 0.36 cm 2 V −1 s −1 on SAM-treated SiO 2 after annealing at 200 °C. Finally, a charge transport mechanism was proposed taking evidence from the anisotropic optical and electrical characteristics of the friction-transferred PBTTT films into consideration.

show abstract

“…The structural observations of PFO based on TEM and selected area electron diffraction patterns were previously published by Chen et al, Misaki et al, and Brinkmann . GIWAXS diffraction study of PFO structure was published by Misaki et al and Kawana et al Here, the structure of the TA PFO was recorded in grazing-incidence geometry using a 2D X-ray detector. The GIWAXS pattern of TA PFO reveals many diffraction spots suggesting the preferential spatial orientation of the PFO molecular crystals (Figure a).…”

Section: Resultsmentioning

confidence: 99%

Correlation between Molecular Stereostructure, Film Microstructure, and Electronic Structure of Polyfluorene and Fluorene Based Alternating Copolymers F8BT and PFO–DBT

et al. 2021

View full text Add to dashboard Cite

Identifying key parameters that can help control molecular ordering in the active layer of high-performance organic devices is an important topical issue. Finding a correlation between the spatial molecular structure of polymer backbones and the thin film's structural and optoelectronic properties is thus of utmost importance. In this paper, the influence of the backbone spatial structures of homopolymer PFO and copolymers F8BT and PFO− DBT with various stereoisomers varying by the up or down spatial orientation of individual chemical units in the comonomer on the film microstructure and electronic structure is studied. The computed energetics of the stereoisomers revealed at least two energetically favorable stereoisomers in both copolymers. These theoretical findings correlate with the thin film's crystallinity analyzed by the GIWAXS method, which showed ill packing in copolymers with stereoisomers. Thus, the molecular stereostructure was identified as a critical parameter that can help control molecular organization in active layers of organic photonic devices.

show abstract

Single-Crystal-like Structure of Poly(9,9-dioctylfluorene) Thin Films Evaluated by Synchrotron-Sourced Grazing-Incidence X-ray Diffraction

Cited by 9 publications

References 29 publications

Oriented Thin Films of Insoluble Polythiophene Prepared by the Friction Transfer Technique

Oriented Thin Films of Insoluble Polythiophene Prepared by the Friction Transfer Technique

Investigation and Control of Charge Transport Anisotropy in Highly Oriented Friction-Transferred Polythiophene Thin Films

Correlation between Molecular Stereostructure, Film Microstructure, and Electronic Structure of Polyfluorene and Fluorene Based Alternating Copolymers F8BT and PFO–DBT

Contact Info

Product

Resources

About