Insight on the generation of near infra-red (NIR) absorbing species in electrochromic Surface-Anchored Metal-Organic Frameworks
Résumé
Due to their verstaility and easy processing, Surface-Anchored Metal-Organic Frameworks (SurMOFs) have received recent interest as promising electrochromic thin films. Herein a step forward in their use and characterization was achieved thanks to the integration of {Zn2(PDICl4)2} SurMOFs in a multi-layer electrochromic device (ECD), based on membrane-like electrolyte. Optical and electrochemical properties of the ECD were fully characterized, revealing a two-step reduction process localized on the organic ligand and involving subsequent near infra-red (NIR) and cyan absorbing states, leading to optical modulation of the films. The species responsible for this absorption were isolated and identified in the reduced states. In parallel to experimental characterization, quantum chemistry was successfully used to investigate the structureproperties relationship of the SurMOF revealing additional information regarding the structure and the local environment of the electrochromic ligand.