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Organic thermoelectric (OTE) materials have been considered to be promising candidates for large area and low‐cost wearable devices owing to their tailorable molecular structure, intrinsic flexibility, and prominent solution processability. More importantly, OTE materials offer direct energy conversion from the human body, solid‐state cooling at low electric consumption, and diversified functions. Herein, we summarize recent developments of OTE materials and devices for smart applications. We first review the fundamentals of OTE materials from the viewpoint of thermoelectric performance, mechanical properties and bionic functions. Second, we describe OTE devices in flexible generators, photothermoelectric detectors, self‐powered sensors, and ultra‐thin cooling elements. Finally, we present the challenges and perspectives on OTE materials as well as devices in wearable electronics and fascinating applications in the Internet of Things. [ABSTRACT FROM AUTHOR]

Optically tunable field‐effect transistors (FETs) with near infra‐red (NIR) light show promising applications in various areas. Now, arylazopyrazole groups are incorporated in the side chains of a semiconducting donor–acceptor (D‐A) polymer. The cis–trans interconversion of the arylazopyrazole can be controlled by 980 nm and 808 nm NIR light irradiation, by utilizing NaYF4:Yb,Tm upconversion nanoparticles and the photothermal effect of conjugated D‐A polymers, respectively. This reversible transformation affects the interchain packing of the polymer thin film, which in turn reversibly tunes the semiconducting properties of the FETs by the successive 980 nm and 808 nm light irradiation. The resultant FETs display fast response to NIR light, good resistance to photofatigue, and stability in storage for up to 120 days. These unique features will be useful in future memory and bioelectronic wearable devices. [ABSTRACT FROM AUTHOR]

2D conductive metal–organic frameworks (2D c‐MOFs) feature promising applications as chemiresistive sensors, electrode materials, electrocatalysts, and electronic devices. However, exploration of the spin‐polarized transport in this emerging materials and development of the relevant spintronics have not yet been implemented. In this work, layer‐by‐layer assembly was applied to fabricate highly crystalline and oriented thin films of a 2D c‐MOF, Cu3(HHTP)2, (HHTP: 2,3,6,7,10,11‐hexahydroxytriphenylene), with tunable thicknesses on the La0.67Sr0.33MnO3 (LSMO) ferromagnetic electrode. The magnetoresistance (MR) of the LSMO/Cu3(HHTP)2/Co organic spin valves (OSVs) reaches up to 25 % at 10 K. The MR can be retained with good film thickness adaptability varied from 30 to 100 nm and also at high temperatures (up to 200 K). This work demonstrates the first potential applications of 2D c‐MOFs in spintronics. [ABSTRACT FROM AUTHOR]

We report the synthesis, characterization, redox behavior, and n-channel organic field-effect (OFET) characteristics of a new class of thieno[3,2-b]thiophene-diketopyrrolopyrrole-based quinoidal small molecules 3 and 4. Under ambient atmosphere, solution-processed thin-film transistors based on 3 and 4 exhibit maximum electron mobilities up to 0.22 and 0.16 cm2 V−1 s−1, respectively, with on-off current ratios ( Ion/ Ioff) of more than than 106. Cyclic voltammetry analysis showed that this class of quinoidal derivatives exhibited excellent reversible two-stage reduction behavior. This property was further investigated by a stepwise reductive titration of 4, in which sequential reduction to the radical anion and then the dianion were observed. [ABSTRACT FROM AUTHOR]

High-performance n-type organic phototransistors (OPTs) based on a core-expanded naphthalene diimide are reported in this letter. The photo responsivity is as high as 27000 AW-1 and photocurrent/dark-current ratio reaches 1.1 × 107 under a white light illumination with a power density of 107 μWcm-2. In such OPTs, persistent photoconductivity (PPC) is observed, which can be instantly eliminated by a positive gate voltage pulse. This is explained in terms of trapped photo holes in the channel. In the light on-off switching test, such PPC also leads to well-reproducible memory effect in the OPTs. [ABSTRACT FROM AUTHOR]

Abstract: Dithienothiophene-phenylene cooligomers with n-hexyloxy or n-dodecyloxy substituents have been synthesized and compared to the previously reported unsubstituted parent compound. The effect of substituents on the thermal, electronic, optical, thin film structure and field-effect transistor (OFET) properties was investigated. Structural phase transitions from highly-ordered nanocrystalline to liquid crystalline were observed at 241 and 213 °C for n-hexyloxy- and n-dodecyloxy-substituted compounds respectively, different from the parent compound. For the alkoxy-substituted compounds, the absorption spectra in thin film blue shift 50 nm, while the fluorescence spectra in thin film red shift 88–100 nm compared to those in solution. The OFET devices based on the alkoxy-substituted compounds exhibit mobilities as high as ca 0.02 cm2V−1s−1 and their performance is sensitive to the alkoxy substituents and substrate temperatures. [Copyright &y& Elsevier]