Silaindacenodithiophene is copolymerized with benzo[c][1,2,5]thiadiazole (BT) and 4,7‐di(thiophen‐2‐yl)benzo[c][1,2,5]thiadiazole (DTBT), respectively their fluorinated counter parts 5,6‐difluorobenzo[c][1,2,5]thiadiazole (2FBT) and 5,6‐difluoro‐4,7‐di(thiophen‐2‐yl) benzo[c][1,2,5]thiadiazole (2FDTBT). The influence of the thienyl spacers and fluorine atoms on molecular packing and active layer morphology is investigated with regard to device performances. bulk heterojunction (BHJ) solar cells based on silaindacenodithiophene donor‐acceptor polymers achieved PCE's of 4.5% and hole mobilities of as high as 0.28 cm2/(V s) are achieved in an organic field‐effect transistor (OFET).

Drain-source current in organic thin-film transistors has been monitored in situ and in real time during the deposition of pentacene. The current starts to flow when percolation of the first monolayer (ML) occurs and, depending on the deposition rate, saturates at a coverage in the range 2-7 MLs. The number of active layers contributing to the current and the spatial distribution of charge carriers are modulated by the growth mode. The thickness of the accumulation layer, represented by an effective Debye length, scales as the morphological correlation length. These results show that the effective Debye length is not just a material parameter, but depends on the multiscale morphology. Earlier controversial results can be unified within this framework.

Functional supramolecular architectures for bottom-up organic nano- and microtechnology are a high priority research topic. We discovered a new recognition algorithm, resulting from the combination of thioalkyl substituents and head-to-head regiochemistry of substitution, to induce the spontaneous self-assembly of sulfur overrich octathiophenes into supramolecular crystalline fibers combining high charge mobility and intense fluorescence. The fibers were grown on various types of surfaces either as superhelices or straight rods depending on molecular structure. Helical fibers directly grown on a field effect transistor displayed efficient charge mobility and intrinsic 'memory effect'. Despite the fact that the oligomers did not have chirality centers, one type of hand-helicity was always predominant in helical fibers, due to the interplay of molecular atropisomerism and supramolecular helicity induced by terminal substituents. Finally, we found that the new sulfur overrich oligothiophenes can easily be prepared in high yields through ultrasound and microwave assistance in green conditions.

A novel supramolecular nanoarchitecture, comprising C(60)/Co porphyrin nanosheets, was prepared by a simple liquid-liquid interfacial precipitation method and fully characterized by means of optical microscopy, AFM, STEM, TEM, and XRD. It is established that the highly crystalline C(60)/Co porphyrin nanosheets have a simple (1:1) stoichiometry, and when incorporated in bottom-gate, bottom-contact field-effect transistors (FETs), they show ambipolar charge transport characteristics.

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A series of benzotrithiophene-containing random terpolymers for polymer solar cells is reported. Through variations of the two other components in the terpolymers, the absorption profile and the frontier energy levels are optimized and 10 maximum power conversion efficiencies are nearly doubled (5.14%) relative to the parent alternating copolymer.Research in organic photovoltaics (OPV) has been attracting much attention over recent years and the development of new light-harvesting donor materials for bulk-heterojunction (BHJ) 15 solar cells with fullerene-based electron acceptors has been progressing rapidly with solar cell efficiencies fast approaching 10%. 1,2 Judicious adjustment of frontier energy levels is an integral part of the process when designing new donor materials for OPV applications. 3,4 This is, firstly, to ensure efficient charge 20 transfer from the excited donor material to the acceptor material and, secondly, to optimize the inherent trade-off associated with pursuing both a high open-circuit voltage and a favourable spectral overlap with the solar radiation.Several strategies to broaden the absorption spectra of the 25 light-harvesting materials and thus better match the solar spectrum can be envisioned. By combining two solar cells in series to create a tandem solar cell, one can utilize two complementary donor materials with different absorption bands and effectively harvest a larger proportion of the solar 30 radiation. 5,6 Alternatively, the incorporation of several different chromophores into one polymeric donor material by means of a random copolymerization approach has also been proven to effectively broaden the absorption spectrum. 7 The latter, single component strategy has recently been applied in OPV devices 35 with some success although clear evidence of significant improvements over the parent systems is limited. [8][9][10] We have previously reported on the synthesis of benzo[1,2-b:3,4-b':5,6-d'']trithiophene (BTT) and on BTT-BT (BT = benzothiadiazole) and BTT-DPP (DPP = diketopyrrolopyrrole) 40 alternating donor-acceptor type copolymers for photovoltaic applications with moderate efficiencies. 11-13 Here we describe a highly successful approach to improving the OPV efficiency significantly by randomly copolymerizing BTT and DPP with a third monomer as illustrated in Scheme 1. By varying the nature 45 and the content of the third monomer we are able to fine tune the frontier energy levels as well as significantly optimise the optical absorption spectrum. Additionally, both the solubility and phase separation can also be further enhanced. As a direct result hereof, we are now able to demonstrate solar cells with power conversion 50 efficiencies as high as 5.14% with these random terpolymers, compared to 2.68% for the alternating copolymer analogue. As illustrated in Scheme 1, three-component microwaveassisted Stille polycondensations were carried out by reacting one equivalent of distannylated C16-BTT with one equivalent of a dibrominated mixture of DPP and a third comonom...

A multiscale investigation of N,N′‐bis(n‐octyl)‐x:y, dicyanoperylene‐3,4:9,10‐bis(dicarboximide), PDI8‐CN2, shows the same molecular arrangement in the bulk and in thin films sublimated on SiO2/Si wafers. Non‐conventional powder diffraction methods and theoretical calculations concur to provide a coherent picture of the crystalline structure. X‐ray diffraction (XRD) and atomic force microscopy (AFM) analyses of films of different thickness deposited at different substrate temperatures indicate the existence of two temperature‐dependent deposition regimes: a low‐temperature (room temperature) regime and a high‐temperature (80–120 °C) one, each characterized by different growth mechanisms. These mechanisms eventually result in different morphological and structural features of the films, which appear to be highly correlated with the trend of the electrical parameters that are measured in PDI8‐CN2‐based field‐effect transistors.

A label-free immunosensor based on an organic electrochemical transistor integrated with an immuno-affinity membrane for cytokine detection at physiologically relevant concentrations is reported.