Fibroin Films Doped with Lithium Ions for Application in Electrochromic Devices

Abstract

Silk fibroin is a commonly available natural biopolymer produced in specialized glands of arthropods, with a long history of use in textile production and also in health cares. The exceptional intrinsic properties of these fibers, such as self-assembly, machinability, biocompatibility, biodegradation or non-toxicity, offer a wide range of exciting opportunities [1]. Silk research is mainly devoted regarding the biomaterials field. Although, it has long been recognized that silk is can be a rich source of inspiration for designing new materials with tailored properties, enhanced performance and high added value for targeted applications, opening exciting new prospects in the domain of materials science and related technological fields, including bio-friendly integration, miniaturization and multifunctionalization. Progresses in new technological fields such as optics, photonics and electronics are emerging [2,3]. The incorporation of polymer electrolytes as components of various devices (advanced batteries, smart windows, displays and super-capacitors) offers significant advantages relative to traditional electrolytes, including enhanced reliability and improved safety. Preliminary tests performed with a prototype electrochromic device (ECD) incorporating the most promising electrolyte composition, silk fibroin films doped with lithium ions (LiTFSI and LiBF4) as electrolyte and WO3as cathodic electrochromic layer, are extremely encouraging. Acknowledgements: This work was supported by Fundação para a Ciência e a Tecnologia (FCT) and Feder (contracts PTDC/CTM-BPC/112774/2009, PEst-OE/QUI/UI0616/2014 and PEst-C/QUI/UI0686/2013) and COST Action MP1202 “Rational design of hybrid organic-inorganic interfaces”. R.F.P.P. acknowledges FCT and program POPH/FSE for a grant (SFRH/BPD/87759/2012). COST Action MP1202 “Rational design of hybrid organic-inorganic interfaces”.M. M. Silva acknowledges CNPq, for the mobility grant provided by this institution.