Proceedings of Online Meetup: Shape-Controlled Nanocrystals: Synthesis, Characterization Methods and Applications (ShapeNC)
Publication date: 6th May 2020
Tin-doped indium oxide (ITO) has been used for decades as suitable and efficient visibly-transparent conducting component of multiple optoelectronic devices. When processed as nanocrystals (NCs), ITO bears localized surface plasmon resonance (LSPR) properties inducing an intense absorption behavior in the near-infrared (NIR) wavelength range [1,2].
In that context, ITO has been highlighted as a benchmark plasmonic electrochromic material allowing for the design of dynamic heat-filtering smart windows devices that show extremely rapid switching kinetics, high levels of NIR optical contrast with maintained visible transparency, and substantial cycling durability [3,4].
Among the various colloidal strategies leading to stable and easily-workable dispersions of ITO nanocrystals, a one-step solvothermal protocol in benzyl alcohol is considered here as an interesting alternative to conventional Schlenk line thermal decomposition approaches. Indeed, this solvothermal route allows for the synthesis of ITO NCs that are straightforwardly dispersible in alcohol media (methanol, ethanol, isopropanol) without the need of extra additives or surfactants.
The obtained dispersions are then used as “precursor inks” in wet deposition processes, especially by spray coating, leading to uniform and highly-covering electrochromic thin films onto conducting glass substrates. Once submitted to an external electrical bias, these films show a selective and controlled modulation ability of the layers NIR transmittance independently of the optical behavior in the VIS range, as a consequence of NCs carrier concentration tuning. Ultimately, optical and electrochemical properties of the generated NIR-modulating layers are shown to be strongly dependent on the colloidal synthetic parameters (including Sn doping ratio) and on the films deposition and post-deposition conditions [5].
Fonds National de la Recherche Scientifique FNRS (PDR PLASMON_EC T.0125.20), Wallonie-Bruxelles International WBI, University of Liège, GREEnMat Laboratory