Development of Electrochromic Devices, Based on Polymeric Gel, for Energy Saving Applications

Abstract

In this work, the implementation of an electrochromic device (10 cm × 10 cm in size) for energy saving applications has been presented. As electrochromic system has been used with an electrochromic solution (ECsol) made by ethyl viologen diperchlorate [EV(ClO4)2], 1,1′-diethyl ferrocene (DEFc) and propylene carbonate (PC), as solvent. The final system has been obtained by mixing the ECsol, described above, with a polymeric system made by Bisphenol-A glycerolate (1 glycerol/phenol) diacrylate (BPA) and 2,2-Dimethoxy-2-phenylacetophenone (Irgacure 651) in a weight percentage equal to 60:40% w/w, respectively. Lithography has been used to make a spacer pattern with a thickness of about 15–20 µm between the two substrates. Micro-Raman spectroscopy confirmed the presence of the EV•+ as justified by the blue color of the electrochromic device in the ON state. Electrochemical and optical properties of the electrochromic device have been studied. The device shows reversible electrochromic behavior as confirmed by cyclic color variation due to the reduction and oxidation process of the EV2+/EV•+ couple. The electrochromic device shows a variation of the % transmittance in the visible region at 400 nm of 59.6% in the OFF state and 0.48% at 3.0 V. At 606 nm the transmittance in the bleached state is 84.58% in the OFF state and then decreases to 1.01% when it is fully colored at 3.0 V. In the NIR region at 890 nm, the device shows a transmittance of 74.3% in the OFF state and 23.7% at 3.0 V while at 1165 nm the values of the transmittance changed from 83.21% in the OFF state to 1.58% in the ON state at 3.0 V. The electrochromic device shows high values of CCR% and exhibits excellent values of CE in both visible and near-infrared regions when switched between OFF/ON states. In the NIR region at 890 nm, electrochromic devices can be used for the energy-saving of buildings with a promising CE of 120.9 cm2/C and 420.1 cm2/C at 1165 nm.

Heterocycle‐ and Amine‐Free Electrochromic and Electrofluorochromic Molecules for Energy‐Saving See‐Through Smart Windows and Displays

“…These observed values are better compared to photochromic mole-cules such as naphthopyrans, that have an optical modulation value around 10 %. [67] The coloration efficiency (CE (η) = ΔA/ Q cm 2 /C; [68] where ΔA is the change in optical absorbance and Q is the amount of charge injected per unit area) was measured by running tandem chronoabsorptometry/chronocoulometry experiments in a spectroelectrochemical cuvette using Pt mesh working electrode, Pt wire counter electrode, Ag/Ag + as QRE, and 0.1 M TBAPF 6 /DCM. The coloration efficiency of TBFCN is 91 cm 2 /C, and for TBFFA is 82 cm 2 /C.…”

Raman Scattering Enhancement through Pseudo-Cavity Modes

“…Raman spectroscopy is a powerful, non-destructive spectroscopic technique useful in many applications, such as the detection of pesticides, toxins, and contaminants in fruits and vegetables [1,2] the early detection of cancer biomarkers [3], microplastics detection [4], biosensing [1,[5][6][7][8][9], systems of biomedical interest [10], carbon-based materials (i.e., graphene) [11,12], thin films [13], polymers [14], cultural heritage investigations [15][16][17][18][19], and many more. The precision level reached by Raman spectroscopy even extends to micro-samples through innovative techniques that involve the so-called "spectral tweezers", a fascinating scenario that is a candidate to become a routine tool for bio-analytical investigations [20].…”