Nonbonding conformational locks including S…O and Se…O interactions were employed to construct the planar π-conjugated systems. For example, based on the electron-neutral alkoxy-functionalized thienyl-vinylene (TVTOEt) building-block co-polymerized, with either BDT (benzodithiophene) or T2 (dithiophene) donor blocks, or NDI (naphthalenediimide) as an acceptor block, are synthesized and characterized. The effect of BDT and NDI substituents (alkyl vs alkoxy or linear vs branched) on the polymer performance in organic thin film transistors (OTFTs) and all-polymer organic photovoltaic (OPV) cells is reported. Co-monomer selection and backbone functionalization substantially modifies the polymer MO energies, thin film morphology, and charge transport properties, as indicated by electrochemistry, optical spectroscopy, X-ray diffraction, AFM, DFT calculations, and TFT response. TVT-based polymer TFTs exhibit stable carrier mobilities in air as high as 0.5 and 0.05 cm2/V-s (n- and p-type, respectively). All-TVT polymer-based complementary inverter circuitry exhibiting high voltage gains (∼50) and ring oscillator circuitry with high fosc(∼1.25 kHz) is readily fabricated from these materials by simple inkjet printing. When n-type polymer is used as an OPV acceptor with PTB7 as a donor, the corresponding blend yields TFTs with ambipolar mobilities of μe = 5.1 × 10−3 cm2 V–1 s–1 and μh = 3.9 × 10−3 cm2 V-1 s–1 in ambient, among the highest mobilities reported to date for all-polymer bulk heterojunction TFTs, and all-polymer solar cells with a power conversion efficiency (PCE) of 1.70%.

Nonbonding "conformational locks" for constructing highly planar π-conjugated systems

251st National Meeting (2016)

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