Visible Light–Near-Infrared Dual-Band Electrochromic Device
Marco Pugliese, Riccardo Scarfiello, Carmela Tania Prontera, Roberto Giannuzzi, Giuseppe Valerio Bianco, Giovanni Bruno, Sonia Carallo, Fabrizio Mariano, Antonio Maggiore, Luigi Carbone, Giuseppe Gigli, Vincenzo Maiorano
Abstract
High Resolution Image Download MS PowerPoint Slide We herein propose a proof of concept of a full dual-band electrochromic (EC) device able to selectively modulate solar light between 300 and 1600 nm. Dual-band control was achieved by exploiting the complementarity and cooperation of two earth-abundant and nontoxic transition metal oxide nanocrystalline materials able to absorb two different spectral regions when electrochemically charged. The active materials were obtained through a microwave-based synthetic protocol able to produce massive amounts of ligand-free water-soluble TiO 2 @WO 3– x colloidal heterostructured nanocrystals. The inorganic heterostructures were deposited via a spray-coating airbrushing method. Graphene was adopted as a near-infrared (NIR) transparent material for the realization of conductive substrates. The nano-dimensions and stable solubility of active materials during the deposition process endorse the development of scattering-free nanostructured electrodes and high device transparency under open-circuit conditions, respectively. The spectro-electrochemical properties of the as-made nanostructured electrodes were evaluated in relation to pure WO 3– x and TiO 2 single nanomaterials and a blend of these. The heterostructured architecture ensures a lower optical haze (around 8% of total radiation) as against the blend, contributing to improving the overall EC performance. The TiO 2 @WO 3– x -based device shows 67% NIR shielding while preserving 60% of visible (VIS) transparency under cool-mode conditions and 89% screening of VIS and NIR radiation under the dark mode. These results represent an important step forward in the development of scalable dual-band EC devices.