Ultrathin Ti_(3)C_(2)T_(x)（MXene） Nanosheet-Wrapped NiSe_(2) Octahedral Crystal for Enhanced Supercapacitor Performance and Synergetic Electrocatalytic Water Splitting

Metal selenides,such as NiSe2,have exhibited great potentials as multifunctional materials for energy storage and conversation.However,the utilization of pure NiSe2 as electrode materials is limited by its poor cycling stability,low electrical conductivity,and insufficient electrochemically active sites.To remedy these defects,herein,a novel NiSe2/Ti3C2Tx hybrid with strong interfacial interaction and electrical properties is fabricated,by wrapping NiSe2 octahedral crystal with ultrathin Ti3C2Tx MXene nanosheet.The NiSe2/Ti3C2Tx hybrid exhibits excellent electrochemical performance,with a high specific capacitance of 531.2 Fg-1 at1 A g-1 for supercapacitor,low overpotential of 200 mV at 10 mA g-1,and small Tafel slope of 37.7 mV dec-1 for hydrogen evolution reaction(HER).Furthermore,greater cycling stabilities for NiSe2/Ti3C2Tx hybrid in both supercapacitor and HER have also been achieved.These significant improvements compared with unmodified NiSe2 should be owing to thestrong interfacial interaction between NiSe2 octahedral crystal and Ti3C2Tx MXene,which provides enhanced conductivity,fast charge transfer as well as abundant active sites,and highlight the promising potentials in combinations of MXene with metal selenides for multifunctional applications such as energy storage and conversion.

Naphthalene diimide based near-infrared luminogens with aggregation-induced emission characteristics for biological imaging and high mobility ambipolar transistors

Organic conjugated materials combining high conductivity with strong solid-state emission are highly desired for organic electronic applications,yet still rather rare.Herein,a novel luminogen(TEN)comprised by linking naphthalene diimides and triphenyl ethylene with vinyl bridges is reported.TEN exhibits aggregation-induced emission(AIE)behavior of a strong nearinfrared fluorescence over 700 nm and the efficiency above 60.5%in the solid state,while also shows promising application in vivo bio-imaging with good permeability and extremely low background.Single crystal of TEN reveals intra-and intermolecular C–H…O hydrogen bonds,contributing to an inclined molecular stacking along the a-axis of the cell,creating a 1 D charge carrier transporting channel under a shortπ-πinteraction distance of 3.42?,which might benefit the solid emission and charge transport ability simultaneously.Solution processed bottom contact,top gate organic field effect transistors based on TEN reveal a high ambipolar charge transport ability with the hole mobility up to 0.13 cm2 V-1 s-1 and electron mobility up to0.010 cm2 V-1 s-1.Further atomic force microscopy and X-ray diffraction analysis on TEN thin film confirm the existence of the1 Dπ-πstacking channel,suggesting the stacking geometry revealed in crystal crucial for facilitating high charge carrier mobility while preserving the strong solid emission at the same time.