White-light electrofluorescence switching from electrochemically convertible yellow and blue fluorescent conjugated polymers

Abstract

We report the study of the fluorescence switching properties of the conjugated copolymers containing triphenylamine, fluorene, benzo[2,1,3]thiadiazole, and cyclic urea moieties. The copolymers show excellent thermal stability and good solubility in polar organic solvents. While the electrofluorescent device (EFD) of P1 emits yellow light under UV excitation, fluorescence intensity is switched off upon electrochemical oxidation. In addition, the fluorescent behavior of the EFD of P1 can be reversibly switched between the non-fluorescent (oxidized) state and the fluorescent (neutral) state with a superb contrast ratio (I f /I f0 ) of 21.4. Furthermore, a white-light electrochemical fluorescence switching device is achieved by blending of P1 (yellow) with P2 (blue). Since the fluorescent conjugated polymers of P1 and P2 have their emission simultaneously quenched under the low working potential, the EFD could show a white-dark state of fluorescence with a high contrast ratio (I f /I f0 ) of 14.6.

Electrofluorochromism in π-conjugated ionic liquid crystals

“…Considering the fluorescence switching performances of other electrofluorochromic devices under similar step duration and fluorescence contrasts, the switching times reported in Table 2 (row d) are comparable to those reported by Kuo and colleagues (t on ¼ 4.33 s; t off ¼ 4.22 s) 30 and are even shorter than those estimated from others (t on B8 s; t off B7 s) 10,31 . These relatively short switching times suggest a fast materials' reduction due to an efficient electron transport via p-p intermolecular interactions, specifically allowed by the anisotropic nature of the mesophase of the thienoviologens.…”

Soluble fluorescent polymeric nanoparticles based on pyrrole derivatives: synthesis, characterization and their structure dependent sensing properties

“…A first approach toward increasing the solubility of PPy is to substitute pyrrole monomer at either carbon 18,19 or nitrogen 20,21 atoms and then polymerize the new derivatives into PPy. [34][35][36] This class of luminescent materials has provided scientists with significant advances in sensing [37][38][39] and fluorescence imaging. 22 Preparation of composites of PPy with carbon materials, [23][24][25] polymeric compounds 26 or nanoparticles of inorganic solids 27 is another way to improve the solubility of PPy.…”

Electroluminochromic Materials and Devices

“…One pioneering example of ELC device was reported by P. Audebert and E. Kim based on tetrazine small molecules . By contrast, fluorescent polymers, compared to inorganic or molecular organic counterparts, are promising candidates for EFC applications because of their rapid transport of electron carriers along the π−conjugated backbone, tunable band‐gap and controllable emission color . Besides, polymeric materials enable solution‐processing of large‐area, flexible or foldable EFC devices, which is of critical importance to printable plastic electronics.…”

“…Notably, Audebert et al presented such an overview article on EFC related small molecular materials and characterization techniques . However, the past 3 years have seen increasing research reports on ELC materials, especially polymers . More recently, several high‐performance ELC devices that were made by versatile methods exhibited multicolor emissions switching, fast response rate, high luminescence contrast and long‐term stability .…”