Self-Powered Flexible Multicolor Electrochromic Devices for Information Displays

The development of self-powered flexible multicolor electrochromic(EC)systems that could switch different color without an external power supply has remained extremely challenging.Here,a new trilayer film structure for achieving self-powered flexible multicolor EC displays based on self-charging/discharging mechanism is proposed,which is simply assembled by sandwiching an ionic gel film between 2 cathodic nickel hexacyanoferrate(NiHCF)and Prussian blue(PB)nanoparticle films on indium tin oxide substrates.The display exhibits independent self-powered color switching of NiHCF and PB films with fast responsive time and high reversibility by selectively connecting the Al wire as anodes with the 2 EC films.Multicolor switching is thus achieved through a color overlay effect by superimposing the 2 EC films,including green,blue,yellow,and colorless.The bleaching/coloration process of the displays is driven by the discharging/self-charging mechanism for NiHCF and PB films,respectively,ensuring the self-powered color switching of the displays reversibly without an external power supply.It is further demonstrated that patterns can be easily created in the self-powered EC displays by the spray-coating method,allowing multicolor changing to convey specific information.Moreover,a self-powered ionic writing board is demonstrated based on the self-powered EC displays that can be repeatedly written freehand without the need of an external power source.We believe that the design concept may provide new insights into the development of self-powered flexible multicolor EC displays with self-recovered energy for widespread applications.

Surface-ligand protected reduction on plasmonic tuning of one-dimensional MoO_(3−x)nanobelts for solar steam generation

Sub-stoichiometric MoO_(3−x)nanostructures with plasmonic absorption via creating oxygen vacancies have attracted extensive attentions for many intriguing applications.However,the synthesis of one-dimensional(1D)plasmonic MoO_(3−x)nanostructures with widely tunable plasmonic absorption has remained a significant challenge because of their serious morphological destruction and phase change with increasing the concentration of oxygen vacancies.Here we demonstrate a surface-ligand protected reduction strategy for the synthesis of 1D MoO_(3−x)nanobelts with tunable plasmonic absorption in a wide wavelength range from 200 to 2,500 nm.Polyethylene glycol(PEG-400)is used as both the reductant to produce oxygen vacancies and the surface protected ligands to maintain 1D morphology during the formation process of MoO_(3−x)nanobelts,enabling the widely tunable plasmonic absorption.Owing to their broad plasmonic absorption and unique 1D nanostructure,we further demonstrate the application of 1D MoO_(3−x)nanobelts as photothermal film for interfacial solar evaporator.The surface-ligand protected reduction strategy provides a new avenue for the developing plasmonic semiconductor oxides with maintained particle morphology and thus enriching their wide applications.

Light-responsive color switching of self-doped TiO_(2-x)/WO_(3)·0.33H_(2)O hetero-nanoparticles for highly efficient rewritable paper

Smart materials that reversibly change color upon light illumination are widely explored for diverse appealing applications.However,light-responsive color switching materials are mainly limited to organic molecules.The synthesis of inorganic counterparts has remained a significant challenge because of their slow light response and poor reversibility.Here,we report a seeded growth strategy for the synthesis of TiO_(2-x)/WO_(3)·0.33H_(2)Ohetero-nanoparticles(HNPs)with networked wire-like structure of〜10 nm in diameters that enable the highly reversible light-responsive color switching properties.For the TiO_(2-x)/WO_(3)·0.33H_(2)OHNPs,T P species self-doped in TiO_(2-x)nanoparticles(NPs)act as efficient sacrificial electron donors(SEDs)and Ti-O-W linkages formed between TiO2-x and WO30.33H2O NPs ensure the nanoscale interfacial contact,endowing the HNPs enhanced photoreductive activity and efficient interfacial charge transfer upon ultraviolet(UV)illumination to achieve highly efficient color switching.The TiO_(2-x)/WO_(3)·0.33H_(2)OHNPs exhibits rapid light response(<15 s)and long reversible color switching cycles(>180 times).We further demonstrate the applications of TiO_(2-x)/WO_(3)·0.33H_(2)O HNPs in ink-free,light-printable rewritable paper that can be written on freehand or printed on through a photomask using UV light.This work opens an avenue for designing inorganic light-responsive color switching nanomaterials and their smart applications.