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Bacterial cellulose (BC) nanofiber-supported polyaniline (PANI) nanocomposites have been synthesized via in situ polymerization of aniline onto BC nanofibers scalfold. Optimized preparation conditions were employed to achieve higher conductivity. The resultant BC/PANI nanocomposites were fully characterized in terms of structure, morphology, and thermal stability. The flake-like morphology of BC/PANI nanocomposites was observed using a field-emission gun scanning electron microscope. By manipulating the ordered flake-type nanostructure, BC/PANI nanocomposites achieved outstanding electrical conductivity as high as 5.1 S/cm. The as-prepared BC/PANI nanocomposites demonstrated a mass-specific capacitance of 273 F/g at 0.2 A.g −1 current density in supercapacitor application, the highest value reported so far for polymer-supported PANI composites.

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Electrode materials with a three-dimensional (3D) network structure and high-conductivity are crucial for the development of robust high-performance supercapacitors. Herein, a facile method has developed for the covalent intercalation of graphene oxide (GO) with bacterial cellulose (BC) fibers via one-step esterification to construct a 3D cross-linked structural scalffords. The as-prepared composite exhibits a tensile strength of 18.48 MPa and an elongation at break of 24%. With an outstanding electrical 10 conductivity of 171 S m -1 , the composite electrode demonstrates a good mass-specific capacitance of 160 F g -1 at 0.4 A g -1 current density. Robust supercapacitor is demonstrated with an outstanding capacitance retention of 90.3% over 2000 recycles. The impressive mechanical and electrochemical properties of covalently intercalated BC/GO composite may open new avenue in developing cross-linked GO nanocomposites for stretchable electronics. This is the first report on the preparation of covalent 15 intercalating BC/GO composite for robust supercapacitor application. Experimental 70Chemicals and materials. All starting materials and reagents were obtained from commercial sources and used without further purification unless otherwise noted. N, N'-dimethyl formamide (DMF) was distilled under vacuum prior to use. Distilled water was used for the preparation of the standard solutions for the 75 adsorption tests.Novel 3D cross-linked BC/GO composite has been prepared with a tensile strength of 18.48MPa and elongation at break of 24%. With an outstanding electrical conductivity of 171 S m -1 , the composite electrode exhibits a mass-specific capacitance of 160 F g -1 and a capacitance retention of 90.3% after 2000 cycling.

Four benzodithiophene-triazoloquinoxaline alternating polymers, PBDTT-BTzQx-EH-C1, PBDT-BTzQx-EH-C1, PBDT-BTzQx-EH-C12 and PBDT-BTzQx-C12, have been designed and synthesized to investigate the correlation of alkyl side chains with the opto-electronic properties of the resulting polymers. The introduction of side chains onto the thiophene spacer or quinoxaline unit lowers the highest occupied molecular orbital energy level of the polymers, while excessive chains prevent the polymer backbone from p-p stacking and result in a decreased short circuit current and fill factor in a photovoltaic application. The bulk heterojunction cells fabricated by blending PBDTT-BTzQx-EH-C1 with [6,6]phenyl-C61-butyric acid methyl ester exhibit a best power conversion efficiency (PCE) of 1.40%, with a short-circuit current density of 4.12 mA cm À2 , an open-circuit voltage of 0.62 V and a fill factor of 55%.The device was further optimized to 2.24% PCE by using PFN (5 nm)/Ca (5 nm) as a co-interfacial layer.

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Selenium-heterocyclic and side-chain strategies for developing near-infrared (NIR) small fused-ring acceptors (FRAs) to further obtain short-circuit current density (J sc ) have proven advantageous in the top-performing polymer solar cells (PSCs). Herein, a new electron-rich central selenium-containing heterocycle core (BTSe) attaching alkyl side chains with a terminal phenyl group was coupled with a difluorinated and dichlorinated electron-accepting terminal 1,1-dicyanomethylene-3-indanone (IC) to afford two types of new FRAs, BTSe-IC2F and BTSe-IC2Cl. Interestingly, in spite of the weaker intramolecular charge transfer, BTSe-IC2F shows a stronger NIR response because of the smaller bandgap (E g opt ) up to 1.26 eV, benefiting from the stronger ordered molecular packing in comparison to BTSe-IC2Cl with an E g opt of 1.30 eV. Additionally, thermal annealing induced an evident red shift by ∼50 nm in the absorption of D18:BTSe-IC2F blend films. Such a phenomenon may be attributed to the synergistic impact of the formation of inward constriction toward the molecular backbone because of the combination of bulky side chains and fluorinated IC as well as the reduced aromaticity of the selenium heterocycle. Consequently, the thermally annealed device based on BTSe-IC2F/D18 achieves a champion power conversion efficiency (PCE) of 17.3% with a high fill factor (FF) of 77.22%, which is among the highest reported PCE values for selenium-heterocyclic FRAs in binary PSCs. The improved J sc and FF values of the D18:BTSe-IC2F film are simultaneously achieved mainly because of the preferred face-on orientations, the wellbalanced electron/hole mobility, and the favorable blend morphology compared to D18:BTSe-IC2Cl. This work suggests that the selenium-heterocyclic fused-ring core (with proper side chains) combined with fluorinated terminal groups is an effective strategy for obtaining highly efficient NIR-responsive FRAs.

The insufficient charge separation and sluggish exciton transport severely limit the utilization of polymeric photocatalysts. To resolve the above issues, we incorporate bountiful carboxyl substituents within a novel benzodiimidazole oligomer and assemble it into a crystalline semiconductor. The photocatalyst is polar, hydrophilic, short-range crystalline, and capable of both hydrogen and oxygen evolution. The introduction of carboxyl side-groups adds asymmetry to the local structure and increases the built-in electric field. Further, accelerated carrier transfer is enabled via the short-range crystallinity. The superior hydrogen and oxygen production rates of 18.63 and 2.87 mmol g À 1 h À 1 represent one of the best performances ever reported among dual-functional polymeric photocatalysts. Our work initiates studies on high-performance oligomer photocatalysts, opening a new frontier to produce solar fuel.