From capacitance-controlled to diffusion-controlled electrochromism in one-dimensional shape-tailored tungsten oxide nanocrystals. (November 2017)

• Record Type: Journal Article
• Authors: Giannuzzi, Roberto; Scarfiello, Riccardo; Sibillano, Teresa; Nobile, Concetta; Grillo, Vincenzo; Giannini, Cinzia; Cozzoli, P. Davide; Manca, Michele
• Is Part Of: Nano energy. Volume 41(2017:Nov.)
• Page Start: 634
• Page End: 645
• Publication Date: 2017-11
• Subjects: Near-Infrared Electrochromism -- Pseudocapacitance -- Tungsten oxide -- 1D-Nanocrystals; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2017.09.058
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: The engineering of electrochemically active films based on structurally and geometrically controlled transition-metal oxide nanocrystals holds promise for the development of a new generation of energy-efficient dynamic windows that may enable a spectrally selective control of sunlight transmission over the near-infrared regime. Herein, the different spectro-electrochemical signatures of two sets of engineered nanotextured electrodes made of distinct anisotropic-shaped tungsten oxide building blocks are comparatively investigated. The electrodes were fabricated starting from corresponding one-dimensional colloidal nanocrystals, namely solid and longitudinally carved nanorods, respectively, which featured identical crystal phase and lattice orientation, but exposed two distinct space-filled volume structures with subtly different lattice parameters and nonequivalent types of accessible surfaces. The shape of nanocrystalline building blocks greatly impacted on the fundamental electrochemical charge-storage mechanisms and, hence on the electrochromic response of these electrodes, due to concomitant bulk and surface-structure effects that could not be entirely traced to mere differences in surface-to-volume ratio. Electrodes made of carved nanorods accommodated more than 80% of the total charge through surface-capacitance mechanisms. This unique prerogative was ultimately demonstrated to enable an outstanding spectral selectivity as well as an extremely efficient dynamic modulation of the optical transmittance at near-infrared frequencies (~ 80% in the range 700–1600 nm). Graphical abstract: We report on the fabrication of electrochromic films embodying engineered nanostructured electrodes made by assembling 1D tungsten oxide nanocrystals with specifically tailored nanoarchitectures. These systems are demonstrated to provide large optical modulation and highly selective control of sunlight transmission in the near-infrared wavelength range. Highlights: Leveraging on two distinct charge accumulation mechanisms in 1D-WO3 nanocrystals. Highlighting the effect of the nanocrystals shape on the spectroelectrochemical signatures. Providing a selective dynamic control of the incoming solar radiation in the NIR range.