Solution‐Processable Copolymers Based on Triphenylamine and 3,4‐Ethylenedioxythiophene: Facile Synthesis and Multielectrochromism

Abstract

In comparison with traditional inorganic electrochromic materials, organic polymers offer advantages such as fast switching speed, flexibility, lightweightness, low cost and nontoxicity, solution‐processability, and color tunability. Herein, a series of hyper‐branched copolymers are synthesized from triphenylamine and 3,4‐ethylenedioxythiophene with different feed ratios via iron(III) chloride (FeCl3)‐mediated oxidative polymerization. The resultant organic‐soluble polymers are easily processable and their corresponding electrochromic devices are found to be stable with limited degradation upon 2500 cycles. In addition to their facile synthesis to achieve solution‐processable polymers, studies also show that the polymers exhibit multielectrochromic properties and give rise to five colored states upon oxidative‐doping by applying an external voltage between 0 and 2.0 V, providing an interesting example of polymers with unique electrochromic switching among up to five colors, from yellow at the neutral state, to pale green, pale purple, orange, and finally gray.

From main-chain conjugated polymer photosensitizer to hyperbranched polymer photosensitizer: expansion of the polymerization-enhanced photosensitization effect for photodynamic therapy

“…[41][42][43] In addition, there are three reaction sites in each TPA group, making it convenient to construct not only linear conjugated polymers, but also hyperbranched ones through ''A 3 + B 2 ''-type polymerization. 44,45 AQ is usually used as an electron-receiving group with an active reversible redox capacity (Fig. S3, ESI †), giving AQ-modified compounds great potential for use as a Type-I PS in PDT.…”

Towards modulating the colour hues of isoindigo-based electrochromic polymers through variation of thiophene-based donor groups

“…5,6 To date, different classes of EC materials have been reported and developed, [7][8][9] including metal oxides, [10][11][12][13] metal complexes, [14][15][16][17][18][19] organic molecules [20][21][22][23][24] and organic polymers. [25][26][27][28][29] Compared to traditional inorganic EC materials, organic polymers offer the advantages of lower production cost and toxicity, better flexibility, lightweightness, and solution processability.…”

Highly electrochemically and thermally stable donor–π–acceptor triphenylamine-based hole-transporting homopolymersviaoxidative polymerization

“…15,16 The high electrochemical stability of triphenylamine (TPA) derivatives allows them to be used in different electrochromic devices. [17][18][19][20][21] In comparison to similar small molecules, TPAbased polymers have better mechanical properties, thermal stability, and film-forming properties. [22][23][24][25][26][27][28][29][30][31][32] The addition of electron-withdrawing fragments into the chemical structure of TPA-based polymers makes it possible to obtain polymers having a donor-acceptor (D-A) motif and thus to tune the electronic and optical properties of the resulting materials.…”

“…8,33 The D-A strategy allows efficiently to regulate the energy of molecular orbitals, electrochemical bandgap, and absorption and emission spectra as well as to improve chargetransporting properties. [34][35][36][37][38] Various p-conjugated copolymers based on TPA have been studied 1,17,25,[39][40][41][42][43][44] including those with D-A structures. 34,39,42,44 However, the general drawbacks of D-A copolymers are that most of them are synthesized via cross-coupling reactions and using toxic organotin compounds as well as expensive catalysts based on noble metals.…”

“…15,16 The high electrochemical stability of triphenylamine (TPA) derivatives allows them to be used in different electrochromic devices. 17–21 In comparison to similar small molecules, TPA-based polymers have better mechanical properties, thermal stability, and film-forming properties. 22–32…”