Polythiophene thin films are widely studied for applications in organic electronics. However, some comparisons are still missing, regarding distinct deposition techniques and regioregularity. Here regioregular and regiorandom alkyl-substituted polythiophene derivatives (P3ATs) were deposited on solid substrates using both Langmuir-Blodgett (LB) and Langmuir-Schaefer (LS) techniques. The main goal was to verify the possible influence of the regioregularity as well the deposition technique on their optical, electrical and electrochemical properties. LB and LS films of regioregular and regiorandom poly(3-butylthiophene) (P3BT) and poly(3-octylthiophene) (P3OT) were deposited onto glass/Indium-Tin-Oxide) substrates and characterized by UV-visible optical spectroscopy, atomic force microscopy, cyclic voltammetry, and conductivity measurements. The results demonstrated the influence of the deposition technique on the electrical outcome, moreover, the regioregularity affected all the performed characterizations. In addition, this paper may be useful to understand how the amphiphilic molecule addition affected the film properties of regioregular and regiorandom P3ATs, particularly the energy diagram provided by the electrochemical and absorption features.
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http://dx.doi.org/10.1088/1361-6528/ab19f0 | DOI Listing |
J Chem Phys
January 2025
Voevodsky Institute of Chemical Kinetics and Combustion of Siberian Branch of Russian Academy of Sciences, Institutskaya 3, 630090 Novosibirsk, Russia.
We developed a technique allowing the direct observation of photoinduced charge-transfer states (CTSs)-the weakly coupled electron-hole pairs preceding the completely separated charges in organic photovoltaic (OPV) blends. Quadrature detection of the electron spin echo (ESE) signal enables the observation of an out-of-phase ESE signal of CTS. The out-of-phase Electron-Electron Double Resonance (ELDOR) allows measuring electron-hole distance distributions within CTS and its temporal evolution in the microsecond range.
View Article and Find Full Text PDFChem Mater
June 2024
Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095-1569, United States.
Conjugated polymers are a versatile class of electronic materials featured in a variety of next-generation electronic devices. The utility of such polymers is contingent in large part on their electrical conductivity, which depends both on the density of charge carriers (polarons) and on the carrier mobility. Carrier mobility, in turn, is largely controlled by the separation between the polarons and dopant counterions, as counterions can produce Coulombic traps.
View Article and Find Full Text PDFThiophenes functionalised in the 3-position are ubiquitous building blocks for the design and synthesis of organic semiconductors. Their non-centrosymmetric nature has long been used as a powerful synthetic design tool exemplified by the vastly different properties of regiorandom and regioregular poly(3-hexylthiophene) owing to the repulsive head-to-head interactions between neighbouring side chains in the regiorandom polymer. The renewed interest in highly electron-rich 3-alkoxythiophene based polymers for bioelectronic applications opens up new considerations around the regiochemistry of these systems as both the head-to-tail and head-to-head couplings adopt near-planar conformations due to attractive intramolecular S-O interactions.
View Article and Find Full Text PDFChem Asian J
April 2024
Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan.
Regioregular and random conjugated polymers based on a boron-fused azomethine unit were synthesized by Sonogashira-Hagihara cross coupling reaction. Although these polymers exhibited similar optical properties in the solution states, a distinct difference was observed in the aggregation forming ability in the film states; scanning electron microscope (SEM) observation indicated the existence of fiber-like aggregates in the spin-coated film of the regioregular polymer, while regiorandom polymer showed no aggregate in the film state. Accordingly, the UV-vis absorption spectrum of the regioregular polymer showed an increased shoulder peak due to the aggregate formation, whereas the random one showed no change.
View Article and Find Full Text PDFACS Appl Mater Interfaces
July 2023
Department of Energy and Chemical Engineering, Incheon National University, Incheon 22012, Republic of Korea.
In this study, we examined how the regioregularity of poly(3-hexylthiophene) (P3HT) affects molecular packing, free volume, charge transport, and gas sensing properties. Our results showed that the presence of regular alkyl side chains on the polymer backbone promoted a high degree of structural order in regioregular P3HT molecules, leading to a compact packing density and reduced free volume. Consequently, it was more challenging for NO molecules to interact with the hole charge carriers in the conductive channel.
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