Organic multiviologen electrochromic cells for a color electronic display application

Abstract

The electrochromic (EC) and optical properties of three new viologen compounds containing 1,1 0 -di-n-heptyl-4,4 0 -bipyridinum dibromide (DHBPDB; C 24 H 38 Br 2 N 2 ), 1-heptyl-4-(4-pyridyl)pyridinium bromide (HPPB; C 17 H 23 BrN 2 ), and 1,1 0 -dis-(p-cyanophenyl)-4,4 0 -bipyridinium chloride (DCBPC; C 12 H 8 N 2 OBr 2 ) for potential use in electrochromism applications were investigated. The repetitive stability of all of the EC cells could be improved through the addition of ferrocene as an electron donor (a counter redox material) to the electrolyte solution under several redox cycles. The experimental results demonstrate that the EC cell showed a reversible color change from clear (tintless) to three different colors with the application of electrochemical stimuli at specific potentials. The color of the EC cells turned red, green, or blue upon electrochemical reduction for DHBPDB, HPPB, and DCBPC in indium tin oxide sandwich-type cells. Because of the different viologen molecules competing to capture electrons and affecting the EC efficiency and life of the multiviologen cells, they could be improved by the optimization of the working voltage in the multiviologen cells from the modification of an operative potential based on the cyclic voltammetry measurements. In this article, we propose a prototype device of multicolor electrochromic display, which provides potential application for multicolor electronic displays or EC paper.

Switchable electrochromic devices based on disubstituted bipyridinium derivatives

“…Bipyridinium derivative salts constitute an attractive family of organic compounds, presenting a large range of applications in liquid crystals, [11][12][13][14][15][16][17] coordination polymers, [18][19][20][21] antimicrobial agents, [22][23][24] herbicides, 25,26 redox indicators 27 as well as functional organic electrochromic materials. [28][29][30][31] In particular, 4,4 0 -bipyridinium salts, also known as viologens, showed a very good electrochromic contrast, switching speed, stability and inherent high turnover. [32][33][34][35] In solution, viologen (V) salts exhibit three redox states: dication (V 2+ ), a radical cation (V + c, blue) and a neutral compound (V 0 ), owing to them undergoing two successive electron-transfer reactions.…”

“…Several research groups have been reported that the switching colours of the bipyridinium salts are function of the nitrogen substituent of dication and counter anions. 1,8,9,[18][19][20][21][28][29][30][31][43][44][45] In this context, our group described the development of electrochromic ionic liquids based on symmetric and non-symmetric disubstituted alkyl-and oxo-bipyridinium cations combined with iodide or bromide, bis(triuoromethanesulfonyl)imide RSC Advances PAPER [NTf 2 ] and docusate [AOT] as anions. 46,47 The most promising electrochromic bipyridinium ionic liquids have been tested in efficient liquid and solid state electrochromic devices using an adequate electrolyte.…”

High‐performance Flexible Complementary Electrochromic Device Based on Plasma Modified WO3Nano Hybrids and V2O5Nanofilm with Low Operation Voltages

“…), metal hybrides, organometallics (Prussian Blue and its analogues), organic materials (viologens, etc. ), polymers (PEDOT (Poly(3,4‐ethylenedioxythiophene)) were used as electrochromic materials . WO 3 displays outstanding reversible color change, coloration efficiency and electrochromic stability among transition metal oxides .…”

Synthesis and characterisation of azobenzene-bridged cationic–cationic and neutral–cationic electrochromic materials

“…Consequently, ECMs have attracted extensive research attention from researchers since Platt [14] reported the electrochromic phenomenon in dyes. ECMs include inorganic materials, such as metal oxides [15][16][17][18], and organic materials, such as phenothiazine [19][20][21][22][23][24], anthraquinone [25][26][27][28][29][30][31][32], viologen [33][34][35][36], thiophene [37][38][39][40], polythiophene [41][42][43][44][45][46][47], polyaniline [48][49][50], polypyrrole [51][52][53][54], and polyimide [55]. Compared with inorganic ECMs, organic ECMs exhibit the unique advantages of high optical contrast, fast switching speed, flexible device fabrication, and a multitude of achievable colors via chemical structure variation.…”