New electrofluorochromic polymer bearing oligoaniline, carbazole, and polyhedral oligomeric silsesquioxane: Synthesis and properties

Abstract

Electrofluorochromic materials have gained much exposure in recent years due to their reversible switching of fluorescence intensity upon electrical potentials. 1 The electrofluorochromic property can be generated from the interplay between electroactive moiety and fluorescence emission moiety. Recently, many electrofluorochromic materials have been prepared and used in photoelectric conversion devices, biological information storage, chemical sensors, and intelligent displays. 2,3 So far, electrofluorochromic materials can be broadly divided into four types: molecular dyads, 4-6 intrinsically switchable fluorophores, 7-9 switchable fluorescent polymers, [10][11][12][13][14][15][16] and switchable fluorescent composites. [17][18][19][20][21][22] Among those, electrofluorochromic polymers are highly desirable for their fast switching speed, facile molecular design and good processability. There are currently a variety of strategies to construct the electrofluorochromic polymers using different electroactive units and fluorescence emission units. For example, Xu and coworkers designed and synthesized a novel alternating conjugated polymer based on thiophene and tetraphenylethene derivatives, which exhibited an aggregation-enhanced fluorescent emission, electrochromic, and electrofluorochromic dualswitching behavior. 10 Kawabata and Goto reported a series of fluorescent conjugated polymers through electrochemical polymerization. The resultant polymer nanofibers showed an interesting electrofluorochromic performance in polarized photoluminescence. 23 Fluorescent polytriphenylamines was also prepared and reported as electroflorochromic materials. [24][25][26][27][28][29] Approving electrofluorochromic performance was displayed, ascribing to effective mitigation of aggregation-caused quenching effect benefiting from unique propeller starburst structure of triphenylamine. For better understanding of electrofluorochromic mechanism and expansion of practical applicability, electrofluorochromic polymers need to be further explored.As the model compounds of polyaniline, oligoanilines have drawn much attention in recent years due to their well-defined structure, good electro-optical properties, and facile molecular design. In light of their reversible electroactivity and relatively low redox potentials, oligoanilines have also been employed as electroactive moiety to construct electrofluorochromic polymers coupled with fluorescent triphenylamine derivatives. 30,31 Expected electrofluorochromic behavior has been revealed through several of electrochemical measurements with the assistance of spectrometric techniques. Due to the coexistence of two types of electroactive moieties (oligoaniline and triphenylamine), the energy transfer could between each other, resulting in an unclear electrofluorochromic mechanism for these system.In this work, we designed and synthesized a new electroactive polymer bearing oligoaniline, carbazole, and polyhedral oligomeric silsesquioxane (POSS) pendants (POCP). Its electrochemical properties, i...

Flexible and Robust Electro‐Optically Responsive Films Based on Novel Silica/Oligoaniline/Carbon Dots Composite

“…As shown in Figure 3d, the peak currents of SOC composite decrease to 96 % and 91 % of its original value after 500 and 1000 cycles, respectively. Compared to our previously reported oligoaniline-based materials, [9,10,[26][27][28][29][30] this composite film shows remarkable improvement of electrochemical durability, attributed to its inherent robust crosslinked architecture. In addition, the hydrolysable siloxane can be anchored to the hydrophilic ITO substrate through the hydrolysis reaction, due to the large number of hydroxyl groups on the ITO surface resulting from the hydrophilic treatment.…”

“…Recently, we developed a series of electrochromic and electrofluorochromic bifunctional polymers bearing oligoanilines and fluorophores. [28][29][30] This strategy provides a new platform for developing oligoaniline-based electrochromic polymers with interesting electro-driven fluorescence switching properties, and may further promote practical applications of oligoaniline-based polymers in displays, intelligent devices, and optoelectronics.…”

“…To these ends we chose a combination of oligoanilines (based on our previous work) [9,10] and carbon dots (chosen for a number of reasons highlighted below). [28][29][30] This strategy provides a new platform for developing oligoaniline-based electrochromic polymers with interesting electro-driven fluorescence switching properties, and may further promote practical applications of oligoaniline-based polymers in displays, intelligent devices, and optoelectronics. [17][18][19][20][21] Introducing oligoanilines in a variety of polymeric architectures can endow them with attractive electroactivity and stimuli-responsiveness, while featuring superior solubility, processability, and tunability.…”

Electroluminochromic Materials: From Molecules to Polymers

“…In recent years, Chao’s group developed a series of random block co-polymers and cross-linked EFC polymers (Figure 16 and Figure 17). Block co-polymer P13 was developed, containing oligoaniline groups as the electroactive unit and carbazole group as the fluorescence emission unit, both attached to the main polymer chain as pendants via amide linkage [60]. In addition, the bulky polyhedral oligomeric silsequioxane (POSS) group was also included as a pendant group to create steric hindrance and, hence, mitigate the aggregation-caused quenching effect of the fluorescence.…”

“…In addition, the bulky polyhedral oligomeric silsequioxane (POSS) group was also included as a pendant group to create steric hindrance and, hence, mitigate the aggregation-caused quenching effect of the fluorescence. Oxidation of P13 generates quinoidal oligoaniline which acts as excitation traps and reversibly quenches the blue fluorescence of carbazole with a contrast of up to 85% and a quick switching time of 11.2 s [60]. Chao et al similarly utilized sterically-bulky POSS groups in the development of a cross-linked polymer network P15 consisting of tetraaniline, carbazole, and POSS, which was synthesised via hydrolysis reaction during cyclic voltammetry, as shown in Figure 17a [61].…”