A new low bandgap polymer POD2T‐DTBT has been synthesized and found to give excellent performances in organic thin‐film transistor (OTFT) and organic photovoltaic (OPV) applications. OTFTs based on POD2T‐DTBT have achieved good hole carrier mobilities of 0.2 cm2V−1s−1 and OPVs based on blends of POD2T‐DTBT and PC71BM have demonstrated promising power conversion efficiencies of 6.26%.

A new series of 2,1,3-benzothiadiazole (BT) acceptors with different conjugated aryl-vinylene side chains have been designed and used to build efficient low-bandgap (LBG) photovoltaic copolymers. Based on benzo[1,2-b:3,4-b']dithiophene and the resulting new BT derivatives, three two-dimensional (2D)-like donor (D)-acceptor (A) conjugated copolymers have been synthesised by Stille coupling polymerisation. These copolymers were characterised by NMR spectroscopy, gel-permeation chromatography, thermogravimetric analysis and differential scanning calorimetry. UV/Vis absorption and cyclic voltammetry measurements indicated that their optical and electrochemical properties can be facilely modified by changing the structures of the conjugated aryl-vinylene side chains. The copolymer with phenyl-vinylene side chains exhibited the best light harvesting and smallest bandgap of the three copolymers. The basic electronic structures of D-A model compounds of these copolymers were also studied by DFT calculations at the B3LYP/6-31G* level of theory. Polymer solar cells (PSCs) with a typical structure of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) (PEDOT):poly(styrenesulfonate) (PSS)/copolymer:[6,6]-phenyl-C(61) (C(71))-butyric acid-methyl ester (PCBM)/calcium (Ca)/aluminum (Al) were fabricated and measured under the illumination of AM1.5G at 100 mW cm(-2). The results showed that the device based on the copolymer with phenyl-vinylene side chains had the highest efficiency of 2.17 % with PC(71)BM as acceptor. The results presented herein indicate that all the prepared copolymers are promising candidates for roll-to-roll manufacturing of efficient PSCs. Suitable electronic, optical and photovoltaic properties of BT-based copolymers can also be achieved by fine-tuning the structures of the aryl-vinylene side chains for photovoltaic application.

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A room temperature stable CuI-coordination polymer was characterized and pyrolysed to form a low density, thermoelectric composite with a relatively high Seebeck coefficient (∼1308 μV K−1) below 100 °C.