Multicolor V_(2)O_(5)/TiO_(2)electrochromic films with fast switching and long lifespan for camouflage and information display

V_(2)O_(5),which has multicolor and energy storage properties,is a promising electrochromic material for multifunctional electrochromic devices,but its practical application is limited by its poor lifespan and long switching time.In this work,high-performance V_(2)O_(5)/TiO_(2)films were fabricated by spraying a V_(2)O_(5)solution on in situ-grown TiO_(2)nanorods.Due to the porous structure formed between the TiO_(2)nanorods and the remarkable electron transfer performance of TiO_(2),the switching time of the V_(2)O_(5)/TiO_(2)films decreased.Moreover,the strong adhesion between the TiO_(2)nanorods and F-doped tin oxide(FTO)glass and the increased surface roughness of the substrates significantly improved the cycling stability of the V_(2)O_(5)/TiO_(2)films.With a large transmittance modulation(47.8%at 668 nm),fast response speed(τ_(c)=5.1 s,τ_(b)=4.2 s),and long lifespan,V_(2)O_(5)/TiO_(2)films were used as electrodes for the electrochromic energy storage device(EESD),which switched in six colors through color overlay:dark orange,sandy yellow,green-yellow,yellow-green,dark green,and dark brown.Inspired by pixel displays,EESDs were designed by segmenting V_(2)O_(5)films to stagger the display of the electrochromic and ion storage layers,which presented 11 types of information based on different combinations of colors.This work provides inspiration for developing multifunctional electrochromic devices,especially for camouflage and information displays.

Self-assembled ultrafine CsPbBr_(3) perovskite nanowires for polarized light detection

One-dimensional(1D)metal halide perovskite nanowire(NW)arrays with high absorption efficiency,emission yield and dielectric constants,as well as anisotropic optoelectronic properties have found applications in energy harvesting,flexible electronics,and biomedical imaging devices.Here,a modified two-step solvothermal method is developed for the synthesis of self-assembled cubic CsPbBr_(3) NW arrays.This method provides facile access to continuous and uniform ultrafine perovskite NWs and well-aligned pure perovskite NW arrayed architectures.Under excitation at 365 nm,the CsPbBr_(3) NWs give a strong blue emission observable to the naked eyes.The CsPbBr_(3) NWs also exhibit strong two-photon excited luminescence under the irradiation with an 800 nm pulse laser.By rotating the polarization angle of the 800 nm laser,strong polarization dependence with a polarization degree up to~0.49 is demonstrated in the selfassembled CsPbBr_(3) NW array,although the CsPbBr_(3) NWs have an isotropic cubic structure.Based on density functional theory(DFT)calculations,this polarization-dependent emission is correlated with the anisotropic charge density distribution of the perovskite NWs.These findings suggest that the ultrafine CsPbBr_(3) NWs with a well-defined self-assembled architecture could be applied as next-generation polarizationsensitive photoelectronic detection materials.