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A series of donor‐acceptor polymers, namely PTEB, PMEB, PEEB, and PPEB, are designed and synthesized for temperature sensing. The polymers are composed of hemi‐isoindigo as the acceptor unit, 3,3″‐bis(dodecyloxy)‐2,2″‐bithiophene as the donor unit, and thiophene as the spacer unit. Carbamate solubilizing side chains are used to increase the solubility of the polymers in a green solvent anisole. Furthermore, the carbamate side chains can be thermally removed to form solvent‐resistant polymers PTNB, PMNB, PENB, and PPNB, respectively. The removal of carbamate side chains also helps to elevate the highest occupied molecular orbital energy level of the polymer, thereby promoting p‐doping. PMNB, PENB, and PPNB films are doped with 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) and used for fabricating temperature sensors on flexible polyethylene terephthalate substrates. The sensors exhibit high temperature coefficient of resistance (TCR) of up to −1.92 (±0.125)% °C−1 at 20–60 °C. This is the highest TCR achieved to date for resistor‐type temperature sensors using a non‐composite single conductive polymer. High sensitivity, green solvent processability, and mechanical flexibility make these temperature sensors promising for use in low‐cost, ubiquitous applications. [ABSTRACT FROM AUTHOR]

Three thiophene- S, S-dioxidized indophenine (IDTO) isomers, 3 a ( E, E, E), 3 b ( Z, E, E), and 3 c ( Z, E, Z), were synthesized by oxidation of an indophenine compound. 3 b and 3 c could be converted into the most-stable 3 a by heating at 110 °C. An IDTO-containing conjugated polymer, PIDTOTT, was prepared using 3 a as a comonomer through a Stille coupling reaction, and it possesses a narrow band gap and low energy levels. In organic field effect transistors (OFETs), PIDTOTT exhibited unipolar n-type semiconductor characteristics with unexpectedly high electron mobility (up to 0.14 cm2 V−1 s−1), despite its rather disordered chain packing. [ABSTRACT FROM AUTHOR]

Organic thin film transistors (OTFTs) are promising candidates as alternatives to silicon TFTs for applications where light weight, large area and flexibility are required. OTFTs have shown potential for cost effective fabrication using solution deposition techniques under mild conditions. However, two major issues must be addressed prior to the commercialization of OTFT-based electronics: (i) low charge mobilities and (ii) insufficient air stability. This article reviews recent progress in the design and development of thiophene-based polymer semiconductors as channel materials for OTFTs. To date, both high performance p-type and n-type thiophene-based polymers with benchmark charge carrier mobility of > 0.5 cm2 V-1 s-1 have been archived, which bring printed OTFTs one step closer to commercialization. [ABSTRACT FROM AUTHOR]

Abstract Solid-state packing and polymer orientation are critical for achieving high charge carrier mobility in organic thin-film transistors. Four side chain substituents, 2-octyldodecyl (−20), 4-octyltetradecyl (−22), 2-decyltetradecyl (−24), and 4-decylhexadecyl (−26), were synthesized to study the effect of side chains on the molecular crystallinity and charge transport properties of diketopyrrolopyrrole–thieno[3,2- b ]thiophene copolymers (DPPTTs). Achieving high-performance DPP-based polymers not only depends on crystallinity, but also on the appropriate proportions of polymer chain orientations. DPPTT22 and DPPTT26 have more coplanarity of the backbone structure and a shorter π–π stacking distance, but the charge mobilities are limited. The objective of this study is to determine the influence of different side chains on the layer distance and π–π stacking regarding 3D carrier channel formation. However, a favorable morphology is also important to improve the charge mobility. DPPTT24 shows improved mobility due to its suitable edge-on-oriented crystallinity and well-interconnected domains with small grain boundaries. Graphical abstract Image 1 Highlights • DPPTT low-bandgap polymers with various branched alkyl side chains synthesized. • Effect of side chains on crystallinity and charge transport of DPPTTs was studied. • Effect of side chains on layer distance and π–π stacking was studied. • DPPTT24 shows improved mobility due to its edge-on oriented crystallinity. [ABSTRACT FROM AUTHOR]

A facile and moderate to high yielding protocol is reported for the synthesis of 2,7-bis(5-bromothiophen-2-yl)-3,8-bis(2-decyltetradecyl)-3,8-dihydropyrimido[4,5- g ]quinazoline-4,9-dione, which can be potentially used to synthesize other pyrimido[4,5- g ]quinazoline-4,9-diones. Moreover, new pyrimido[4,5- g ]quinazoline-4,9-diones synthesized by this route can potentially be used as organic semiconductors. [ABSTRACT FROM AUTHOR]

Abstract: Alkyl amine stabilized gold nanoparticles (Au-NPs), with diameters of 1–10nm, deposited at the interface of the hole-collecting buffer layer [poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)] and poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester (P3HT):(PCBM) active layer were found to significantly reduce solar cell performance. The reduced performance was attributed to interactions between the amine based organic stabilizers and the PEDOT:PSS buffer layer. This was confirmed by screening various organic stabilizing ligands at the interfacial layer and measuring the resulting solar cell performances. In addition, it was found that alkyl thiol capped Au-NPs (5–10nm) incorporated at the buffer layer and their corresponding alkyl thiol stabilized ligands had a lesser impact on the overall performance of the polymer solar cells. [Copyright &y& Elsevier]

Abstract: ZnO nanopillars are grown on a ZnO seed layer on fluorine-doped tin oxide (FTO)-coated glass substrates for the fabrication of inverted organic photovoltaic devices based on poly(3-hexylthiophene) and (6,6)-phenyl C61-butyric acid methyl ester. It is found that the oriented ZnO nanopillars play an important role in collecting photogenerated electrons and act as an electron-transport path to the cathode. OPV devices with a ZnO nanopillar layer grown on a ZnO seed layer exhibit a threefold increase in power conversion efficiency compared with that of devices with a ZnO seed layer only. [Copyright &y& Elsevier]

A novel class of liquid-crystalline organic semiconductors based on 2,5′-bis-[2-(4-pentylphenyl)vinyl]-thieno(3,2-b)thiophene and 2,5′-bis-[2-(4-pentylphenyl)vinyl]-(2,2′)bithiophene were synthesized through proper structural design. The materials exhibited high field-effect mobilities up to 0.15 cm2V−1s−1and current on/off ratio of 1 × 106. The high performance is attributed to their abilities to form highly ordered structures through molecular packing, which is revealed by single-crystal and thin film X-ray diffraction (XRD). The structures were analyzed by polarized optical microscope and showed obvious changes in texture corresponding to the phase changes in DSC diagrams, indicating their abilities to form liquid-crystalline structures. High environmental stabilities have been demonstrated with these new compounds, which is consistent with their low HOMO levels and large band gaps. In addition, UV−vis spectra of the thin films formed from these compounds have showed that their absorption peaks mainly appear in the range of ultraviolet spectrum region, indicating they could be used for the application of those circuits requiring transparency such as optoelectronic devices. [ABSTRACT FROM AUTHOR]