Controlled Synthesis of Poly[(3-alkylthio)thiophene]s and Their Application to Organic Field-Effect Transistors

Abstract

Regioregular polythiophenes have been widely used in organic electronic applications due to their solution processability with chemical modification through side chain engineering, as well as their microstructural organization and good hole transport properties. Here, we introduce alkylthio side chains, (poly[(3-alkylthio)thiophene]s; P3ATTs), with strong noncovalent sulfur molecular interactions, to main chain thienyl backbones. These P3ATTs were compared with alkyl-substituted polythiophene (poly(3-alkylthiophene); P3AT) variants such that the effects of straight (hexyl and decyl) and branched (2-ethylhexyl) side chains (with and without S atoms) on their thin-film morphologies and crystalline states could be investigated. P3ATTs with linear alkylthio side chains (P3HTT, hexylthio; P3DTT, decylthio) did not attain the expected higher organic field-effect transistor (OFET) mobilities with respect to P3HT (hexyl) and P3DT (decyl) mainly due to their lower regioregularity (76−78%), although P3ATTs exhibit an enhanced tendency for aggregation and compact molecular packing, as indicated by the red-shifting of the absorption spectra and the shortening of the π−π stacking distance, respectively. Moreover, the loss of regioregularity issue can be solved by introducing more soluble 2-ethylhexylthio branched side chains to form poly [3-(2-ethylhexylthio)thiophene] (P3EHTT), which provides enhanced crystallinity and efficient charge mobility (increased by up to a factor of 3) with respect to the poly(2-ethylhexylthiophene) (P3EHT) without S atoms in the side moieties. This study demonstrates that the presence of side chain alkylthio structural motifs with nonbonded interactions in polythiophene semiconductors has a beneficial impact on the molecular conformation, morphologies, structural packing, and charge transport in OFET devices.

Group 16 conjugated polymers based on furan, thiophene, selenophene, and tellurophene

“…The regioselectivity of the metathesis reaction is influenced to a large extent by the ring substituents. The steric properties, 23 electronic nature, [24][25][26][27] and potential heteroatom coordination 28 of substituents may either individually or collectively affect the regioselectivity. Heterofunctional monomers are used to obtain exclusive metathesis product, which is achieved by either taking advantage of reactivity differences of different halogens (mostly Br/I) 29 or deprotonating monohalogenated monomer precursors.…”

“…3), including the whole series of Group 16 aromatic heterocycles. A large library of substituents has been established to diversify thiophene monomers, including alkyl, 41,42 alkyl ester, 43,44 alkyl ether, 45 oligoethylene glycol, 24,[45][46][47] thioether, 25,48 substituted aryl, 28,[49][50][51][52][53] alkynyl, 54 and a-ketal. 55 However, the diversity of functional groups is limited by their compatibility with relatively active Grignard and Negishi reagents.…”

Metallo-Supramolecular Rod–Coil Block Copolymer Thin Films for Stretchable Organic Field Effect Transistor Application

“…Then, the upper shearing plate was lowered to contact the substrate. The polymer semiconductor thin films were deposited by the shearing method with optimized conditions, as previously reported . The solution shearing deposition was performed under an ambient atmosphere at a substrate temperature of 25 °C and with a fixed moving speed of 1 mm s –1 , followed by postannealing at 55 °C under vacuum overnight.…”

“…The polymer semiconductor thin films were deposited by the shearing method with optimized conditions, as previously reported. 59 The solution shearing deposition was performed under an ambient atmosphere at a substrate temperature of 25 °C and with a fixed moving speed of 1 mm s −1 , followed by postannealing at 55 °C under vacuum overnight. Finally, the 60 nm Au electrodes were deposited onto the polymer films under high vacuum through a shadow mask defining channels of 20 μm in length (L) and 1500 μm in width (W).…”

A DFT analysis of electronic, reactivity, and NLO responses of a reactive orange dye: the role of Hartree-Fock exchange corrections

“…Since it was discovered in the 60's [1], nonlinear optics (NLO) has figured as a prominent field in the science of materials. Organic and inorganic chromophores with higher NLO response can be used to built a variety of devices, such as field-effect transistors [2,3], light-emitting diodes [4,5], solar cells [6][7][8], and sensors [9,10] that can improve logical circuits. The biggest advantage of such devices is their data transfer speed, once part of the information is performed at the light-speed limit.…”