Highly Fluorescent Thienoviologen‐Based Polymer Gels for Single Layer Electrofluorochromic Devices

Abstract

A highly fluorescent electrofluorochromic gel with quantum yields as high as 67% is prepared by incorporating the thienoviologen fluorophore 4,4′‐(2,2′‐bithiophene‐5,5′‐diyl)bis(1‐nonylpridinium)bistriflimide into a polymeric matrix. The fluorescent emission spectrum of the gel at low percentages of thienoviologen shows a strong band at 530 nm. A new intense fluorescence band at 630 nm can be induced by fluorophore aggregation. Single layer electrofluorochromic devices were readily prepared by sandwiching the polymer gels between two indium tin oxide (ITO) electrodes. The fluorescence intensity can be easily modulated between a fluorescent and a quenched state, in a wide visible spectral range, by direct electrochemical reduction of the thienoviologen fluorophore. It exhibits three reduction states, each with different emission properties. The reversible interconversion among these states leads to a high electrofluorochromic stability of the device, exhibiting switching times of a few seconds and, to the best of our knowledge, the highest contrast ratio (337).

Mesomorphism and electrochemistry of thienoviologen liquid crystals

“…The CV diagrams in Fig. 35,36 However, a quantitative study aimed at the comprehension of this behaviour has never been performed and, therefore, a clear explanation of the electrochemistry of thienoviologens in solution has never been provided. 12,25,35 Indeed, at 30 mV s À1 the voltammogram displays two reduction peaks due to the formation of the radical-cation TV + and the neutral TV species, respectively, at negative half-wave potentials of À0.75 V and À0.96 V vs. Ag/AgCl.…”

Phosphorescent Ionic Iridium(III) Complexes Displaying Counterion‐Dependent Emission Colors for Flexible Electrochromic Luminescence Device

“…[44] Complexes [(CZPY) 2 IrNH] + X − (X − = PF 6 − , I − , Br − , Cl − ) have been prepared in three steps. [44] Complexes [(CZPY) 2 IrNH] + X − (X − = PF 6 − , I − , Br − , Cl − ) have been prepared in three steps.…”

“…[44] Complexes [(CZPY) 2 IrNH] + X − (X − = PF 6 − , I − , Br − , Cl − ) have been prepared in three steps. Next, [(CZPY) 2 IrNH] + PF 6 − (Figure 1a) was prepared by the bridge-splitting reaction of [Ir(CZPY) 2 Cl] 2 followed by complexation with the NH ligand, and then adding an excess of potassium hexafluorophosphate to the reaction at a room temperature. Next, [(CZPY) 2 IrNH] + PF 6 − (Figure 1a) was prepared by the bridge-splitting reaction of [Ir(CZPY) 2 Cl] 2 followed by complexation with the NH ligand, and then adding an excess of potassium hexafluorophosphate to the reaction at a room temperature.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12] The optical properties of these materials can be regulated by the external stimuli, such as electric field, vapor, temperature, pH value, mechanical force, UV irradiation, ions, etc. [1][2][3][4][5][6][7][8][9][10][11][12] The optical properties of these materials can be regulated by the external stimuli, such as electric field, vapor, temperature, pH value, mechanical force, UV irradiation, ions, etc.…”

Luminescent ion pairs with tunable emission colors for light-emitting devices and electrochromic switches

“…34 Beneduci and co-workers have shown an ECL-active polymer gel based on the conversion of the redox states, in which the emission properties of the polymer depend on the fluorophore contents and the voltages applied. 35 We have also reported a series of phosphorescent iridium( iii ) complexes containing a protonating functional group, which exhibited evident emission color change induced by an electric field. 36–38 However, special functional groups, such as redox active or protonating groups, in these electrochromic luminescent materials may reduce their stability, especially toward redox reagents and pH values.…”