Electrochromic devices using Fe(II)‐based metallo‐supramolecular polymer: Introduction of ionic liquid as electrolyte to enhance the thermal stability

Abstract

We fabricated electrochromic (EC) devices with Fe(II)‐based metallo‐supramolecular polymer (polyFe), 1‐butyl‐1‐methyl‐pyrrolidinium bis(trifluoromethanesulfonyl)imide (BMPyr(NTf)2) ionic liquid (IL), and Prussian blue (PB) as electrochromic layer, electrolyte layer, and counter layer, respectively. Thermal stability and ionic conductivity of BMPyr(NTf)2 IL was measured by thermogravimetric analysis (TGA) and impedance analysis to be 380°C and approximately 7.8 × 10−4 S/cm, respectively. The fabricated device showed reversible electrochromism between bluish‐violet and colorless by applying +3.0/−1.5 V alternately. The 65% of the original EC contrast remained in the device after the repeated changes for 100 cycles at 100°C.

Green-to-Black Electrochromic Copper(I)-Based Metallo-Supramolecular Polymer with a Perpendicularly Twisted Structure

“…Metallo-supramolecular polymers (MSPs) are a new type of coordination polymer, synthesized by complexation of metal ions with multitopic organic ligands. − MSPs are expected to show unique electrochemical, optical, magnetic, self-healing, catalytic, or sensing properties as a result of metal–ligand interactions, reversible polymer formation/depolymerization, etc. The properties of MSPs have received attention because of the wide range of applications of these materials, for example, in energy and information storage, electrochromic (EC) displays, sensors, stimulus-responsive gels, photovoltaics, photoluminescent devices, and biorecognizers. − …”

“…In other words, monometal complexes with specific colors can be used as polymeric EC materials. Blue-, red-, and yellow MSPs are relatively easy to obtain because these colors require only a single absorption frequency in the visible region of the spectrum (blue: ∼600 nm; red: ∼500 nm; yellow: ∼450 nm). − On the other hand, it is difficult to prepare green- or black MSPs because green materials require two absorptions (yellow at ∼450 nm and blue at ∼600 nm), whereas a black material requires a broad absorption covering the entire visible region from 400 to 800 nm. , One way to obtain a green material is simply by mixing a blue polymer with a yellow one. For black material, a mixture of polymers of the three primary colors would be acceptable on the basis of additive color theory.…”

Ru(II)-Based Metallo-Supramolecular Polymer with Tetrakis(N-methylbenzimidazolyl)bipyridine for a Durable, Nonvolatile, and Electrochromic Device Driven at 0.6 V

“…The qualitative and quantitative elemental composition of the polymer was investigated by XPS study (Figure b). The observed peaks at 197.6, 400.8, 463.2, 485.6, and 532 eV suggest the presence of Cl, N, Ru, and O. , The two peaks at 463.2 and 485.6 eV (Figure S6 of Supporting Information), which are assigned for Ru 3p 3/2 and Ru 3p 1/2 , respectively, indicate the existence of the divalent state of Ru in polyRu-L Bip . , The peak at 197.6 eV was matched with Cl 2p as counter ions (Cl – ). The atomic ratio of Ru and N was 1:9.7, which was close to the calculated value of 1:10.…”

Flexible electrochromic devices prepared on ultra-thin ITO glass

“…18 Therefore, PB is suitable as counter electrode for MEPE-based ECDs. 19 Moreover, it can also be applied via wet-chemical deposition. 20 The demand for polymeric or organometallic EC materials has been notably increasing in recent years due to their potential applications in next generation flexible, lightweight ECDs with high optical contrast, fast response times and low power consumption.…”