Search

In this study, six conjugated oligomers containing D–A structures were synthesized using the Stille coupling reaction and named PHZ1–PHZ6. All the oligomers utilized demonstrated excellent solubilities in common solvents and notable color variations in the domain of electrochromic characteristics. By designing and synthesizing two electron-donating groups modified with alkyl side chains and a common aromatic electron-donating group, as well as cross-binding them with two electron-withdrawing groups with lower molecular weights, the six oligomers presented good color-rendering efficiencies, among which PHZ4 presented the best color-rendering efficiency (283 cm2·C−1). The products also demonstrated excellent electrochemical switching-response times. PHZ5 presented the fastest coloring time (0.7 s), PHZ3 and PHZ6 presented the fastest bleaching times (2.1 s). Following 400 s of cycling activity, all the oligomers under study showed good working stabilities. Moreover, three kinds of photodetectors based on conducting oligomers were prepared, and the experimental results show that the three photodetectors have better specific detection performances and gains. These characteristics indicate that oligomers containing D–A structures are suitable for use as electrochromic and photodetector materials in the research. [ABSTRACT FROM AUTHOR]

Four new multifunctional polymers (P1, P2, P3, and P4) containing EDOT units were synthesized by the Stille coupling reaction. A PL spectrum test found that the introduction of large conjugated groups led to strong fluorescence emission in all polymers. Among the electrochromic and switch properties, these polymer films exhibited reversible color changes, as well as good coloring efficiency. Electrochemical experiments found that the initial oxidation potentials of the polymers were 1.27 V, 1.67 V, 1.78 V, and 1.58 V, respectively. Among them, P3 showed a higher coloring efficiency (283.3 cm2·C−1), and P2 showed a shorter response time (tc = 2.2 s, tb = 2.8 s). These polymers all exhibited electrochromic and resistive switching storage characteristics. They have good solubility in many organic solvents. In the resistance switch memory characteristics, all polymers had obvious memristive properties, and P4 exhibited a larger switch current ratio (2527.42) and a smaller threshold voltage (0.9 V). [ABSTRACT FROM AUTHOR]

A series of aromatic polyesters were synthesized from dicarboxylic acids, containing pendent triphenylamine substituted with phenothiazine, and five different kinds of bisphenols. The aromatic polyesters exhibited good solubility in organic solvents due to bulky propeller-like triphenylamine and butterfly-like conformation of phenothiazine, which were convenient for the polymers to fabricate films and devices by spin- or inject-coating. They also revealed good thermal stability with 10% weight lost at 420 °C. In addition, the polymer showed a strong yellow fluorescence at 522 nm in the THF solution and irregular solvatochromic characteristic in polar solvents. Furthermore, their films had well reversible redox process in the range of 0–1.2 V with the color changing from colorless neutral to red in the range of 0.80–0.85 V. The calculated HOMO and LUMO energy levels of polyesters demonstrated their potential application as photoelectrical materials. [ABSTRACT FROM AUTHOR]

A series of Schiff bases (SBs) were synthesized from 2-furancarboxaldehyde and different triphenylamine (TPA) derivatives to investigate the influence of substituted groups on the properties of SBs. The structures of SBs were characterized by means FTIR, NMR spectroscopy and elemental analysis (EA); the results showed an agreement with the proposed structure. The electrochemical, electrochromic and acidochromic properties of SBs were investigated by UV–vis spectroscopy and cyclic voltammetry (CV) techniques. The obtained SBs exhibited stable and reversible electrochromic properties. These anodic coloring films showed high coloration efficiency (CE). Furthermore, multiple reversible color states were also observed with the concentration changes of HCl vapor. [ABSTRACT FROM AUTHOR]

Highlights: [•] It is a simple approach to obtain polyimides by Michael addition reaction. [•] The prepolymers had excellent solubility in many common organic solvents. [•] The polyimides film revealed good thermal stabilities and electrochromic characteristics. [Copyright &y& Elsevier]

Abstract: Two series of novel polyazomethines (PAMs) PIa–PIe, PIIa–PIIe were prepared via the direct polycondensation from N,N′-bis(4-aminophenyl)-N,N′-diphenyl-1,4-phenylenediamine, and N,N′-bis(4-aminophenyl)-N,N′-diphenyl-4,4′-biphenyldiamine with various dicarboxaldehyde such as phthaldialdehyde, 1,3-isophthalaldehyde, terephthalaldehyde, 4,4′-diformyltriphenylamine, 5-thiophene-dialdehyde. The variation of the backbone structure significantly affected the dihedral angles and changed the electronic properties of PAMs. The obtained PAMs exhibited stable and reversible electrochromic properties and reversible color change. The color of PAMs could be varied from initial yellowish to red, violet or blue via electrooxidation. And multiple reversible colors states were also observed with pH and chemical doping. Considering the sensitive chromic properties of PAMs, they will have potential applications for display device, chemical sensor, et al. [Copyright &y& Elsevier]

Abstract: A new triphenylamine-containing aromatic diamine, N-(4-triphenylamine-phenyl)-3,5-diaminobenzamide, was synthesized from 4-aminotriphenylamine and 3,5-dinitrobenzoyl chloride. A series of novel aromatic polyimides with pendent triphenylamine units were prepared from the newly synthesized diamine and various aromatic tetracaboxylic acid dianhydrides via polycondensation. These polyimides have inherent viscosities of 0.36–0.47dl/g. They are readily soluble in many organic solvents, such as NMP, DMAC, DMF and DMSO. They can be solution-cast into transparent, tough, and brittle films with good mechanical properties. These aromatic polyimides display outstanding thermal stabilities, i.e. 10% weight-loss temperatures in excess of 540°C under nitrogen. Cyclic voltammograms of the polyimide films on an indium-tin oxide (ITO)-coated glass substrate exhibit one pair of reversible redox couple at half-wave oxidation potentials (E 1/2) around 0.82–0.850V, respectively, versus Ag/AgCl in acetonitrile solution. The electrochromic properties were examined by spectroelectrochemical methods. All the polymer films reveal good electrochemical and electrochromic stability by repeatedly switching electrode voltages, with coloration change from the green neutral state to the red or blue oxidized state. [Copyright &y& Elsevier]

Abstract: Poly(3,5-diaminobenzotrifluoride) (PDAT) films with controlled thickness have been successfully grown on fluorine-doped tin oxide (FTO) glass substrates using the cyclic voltammetry (CV) method at room temperature, followed by Pt particles depositing on the PDAT films by electrochemical method. The morphology of PDAT films and aggregation of Pt particles were investigated by scanning electron microscopy (SEM). Fourier transform infrared (FT-IR) spectra and UV–vis absorption spectra were employed to characterize the chemical structure of PDAT. Solar cells made of PDAT film which were used as counter electrode and the N719 dye-sensitized TiO2 used as anode were fabricated. The photovoltaic performance of the solar cells was tested. We investigated the influence of various Pt loadings on efficiency of solar cells. With the increasing of Pt loadings, the morphologies changed and the efficiency of solar cells increased. We also investigated the electrochromic properties of PDAT. As the voltage increased, the color of the PDAT film turned from pale yellow to yellow with good reversibility. It shows that PDAT can be used as electronic display materials. [Copyright &y& Elsevier]

A new series of soluble electrochromic polyamides (PAs) were synthesized from the reaction of 4,4’-diamino-4”-(quinolin-8-yloxy) triphenylamine (DAQTPA) with five dicarboxylic acid via direct polycondensation process, respectively. These amorphous materials showed the decomposition temperature at 5% weight loss was over 400 °C in N 2 atmosphere. The influence of aliphatic structure for spectroscopic properties of PA was measured by UV–vis and fluorescent (PL) spectroscopies and explained by the theory of the frontier molecular orbitals. It can be easily determined that DAQTPA performs the most strongly responsive to Cu 2+ with obvious enhancement in UV–vis and quenching in PL profiles, which are completely different from the response of other metal ions. PAs also showed the exclusively selective response for Cu 2+ in UV–vis spectra. A pair of obvious redox peaks was observed in the cyclic voltammetry (CV) test of PAs accompanied with the distinct color changed from original yellowish to green or blue. The PA bearing the pendent quinolin-8-yloxy performed as an electron-donating group was more stable in the electrochemical process. [ABSTRACT FROM AUTHOR]

Two series of novel aromatic polyurethanes containing triphenylamine derivatives were synthesized via polycondensation of 4-(3,6-diisocyanato-9H-carbazol-9-yl) aniline, N,N-bis(4-isocyanatophenyl) benzene-1,4-diamine with various dihydroxy monomers such as phenolphthalein, 2,2-bis (4-hydroxyphenyl) -propane, 4,4'-dihydroxybiphenyl, 4, 4'-bishydroxy benzophenone and bisphenolfluorene, respectively. The variation of the backbone structure affected the electronic properties, solubility, molecular weight and thermal stability of polyurethanes. The thermal stability of polyurethanes was studied by the gravimetric analyzer. The electrochromic performance was investigated by cyclic voltammograms and spectroelectrochemical methods, which showed stable and reversible electrochromic properties. Besides, the color of polyurethanes can be varied from initial colorless to green then to blue via electro-oxidation, which indicates the polyurethanes will have potential applications for eletrochromic materials. In addition, the PUs exhibited memory characteristic. The result indicated the PUs could be applied in smart window and memory devices. [ABSTRACT FROM AUTHOR]

• Polyamides show solvochromic effects and large stokes shift. • Polyamides have specific fluorescent response to TNP and HCl. • Polyamides have excellent electrochromic and electrofluorescent properties. • The constructed electrochromic devices can display multiple colors. The pyrene group was directly connected to the triarylamine (TAA) unit through a benzene bridge via the Suzuki reaction to successfully prepare the diamine monomer. A series of new polyamides (PAs) based on TAA units were prepared by polycondensation. The PAs exhibited good solution processability and high thermal stability with the char yield in excess of 53 % at 800 °C in air atmosphere. In solvents with different polarities, these PAs showed solvatochromic effect and large stokes shift. Strongly photoluminescent PAs have a sensitive stimulus response to explosive and hazardous gas, and its fluorescence is easily turned off by the addition of trinitrophenol (TNP) and hydrogen chloride (HCl). And achieve fluorescence switching between exposure to HCl and ammonia (NH 3) gas. The PAs exhibited a reversible color response in the electrochemical oxidation process, with no significant degradation in current and transmittance after 200 cycles. The sandwich structure multicolor electrochromic device can achieve electrochromic performance applied by different voltages. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: A novel series of triphenylamine-containing aromatic polyurethanes (PUs) were synthesized via polymerization of N,N-bis (4-isocyanatophenyl) aniline monomer with different dihydroxy compounds. The structures of PUs were characterized by means of Fourier transform infrared (FTIR), 1H nuclear magnetic resonance (1H NMR) spectroscopy which showing an agreement with the proposed structure. All the PUs are soluble in a variety of organic solvents, and could be cast into transparent, tough films with good mechanical properties. The effects of molecular structure on thermal stability of the polymers were studied by thermo-gravimetric analyzer. The electrochemical behaviors were investigated by cycle voltammetry (CV) method, and the result revealed that there were a pair of reversible oxidative redox couples at potentials of 0.33V and 1.15V vs Ag/AgCl in acetonitrile solution. The electrochromic properties were examined by spectroelectrochemical methods. All the PUs exhibited excellent reversibility of electrochromic characteristics by continuous cyclic scans between 0V and 1.6V, with a color changing from yellow to blue. [Copyright &y& Elsevier]

In this paper, a sequence of polyphosphazenes (PPZs) as electrochromic (EC) and sensor materials have been designed and synthesized by introducing chromophores, (4-(diphenyl amino)phenyl) methanol (CH1) for PPZ1, 3-(4-(dimethyl amino) phenyl)-2-(4hydroxyphenyl) acrylonitrile (CH2) for PPZ2, and CH1 and CH2 for PPZ3 into the main chain. In terms of EC performance, PPZ1 shows the best EC performance among the three PPZs which can achieve 60 % optical contrast at 690 nm with good cyclic stability within 1000 s and fast switching response time (t color/ t bleach = 1.2 s/0.6 s). Compared to PPZ1, the oxidation potential of PPZ3 is reduced compared to PPZ1. PPZ2 and PPZ3 as sensors are more sensitive for the detection of 2,4,6-trinitrophenol (TNP) and trifluoroacetic acid (TFA) compared to PPZ1. What's more, PPZs can be used in memory devices with non-volatile flash memory performance and switching current ratios of 103:102.4:1, 104.7:101.3:1 and 103.5.:100.6:1 respectively. Therefore, PPZs have the promising prospect in optoelectronic field. [Display omitted] • Three multifunctional PPZs grafted with various chromophores were designed and synthesized. • PPZ3 has decreased oxidation potential. • PPZ2 & PPZ3 exhibit higher sensitivity in detecting TNP & TFA. • PPZs show good memory storage properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polyamides with D-A segments for electrochromic and memory storage performance improvements. • The triphenylamine moiety with substituted methoxyl group improves the switching cycle stability. • Polyamides exhibit high optical contrast, outstanding coloration efficiency, fast response and long-term cycle. • Polyamides also serve as memristors with accessible threshold voltage and long retention time. With the aim to obtain multifunctional durable electrochromic (EC) devices, we propose an effective strategy by introducing weak electron acceptor segment with suitable bandgap and oxidation potential. A series of quinoxaline-based units polyamides (PAs) (denoted as T 2 BPA-CA, T 2 BPA-OA, T 2 BPA-TP, and T 2 BPA-SA) were prepared from a novel donor–acceptor-donor (D-A-D) type diamine with weak electron acceptor quinoxaline and connected with two methoxyl-substituted donor triphenylamine, 10,13-bis[4-aminophenyl (4-methoxyphenyl) amino]-dibenzo[a,c]phenazine, and four dicarboxylic acids, which are high soluble in various organic solvents and exhibit excellent thermostability. Furthermore, the T 2 BPA-SA thin film exhibits excellent EC performance with outstanding optical contrast (50 %), high coloration efficiency (230 cm2 C−1) and impressive cycle stability (optical contrast remains 80 % over 1400 cycles) in the NIR range. Meanwhile, all of these PAs are served as memristors and exhibit typical nonvolatile ternary memory, realizing an accessible threshold voltage of −0.65 V, a retention time of more than104 s and high current switch ratio (103.52:102.43:1). Overall, this work implies the great potential of these PAs in EC displays and memory storage devices. [ABSTRACT FROM AUTHOR]

Abstract Four novel multifunctional electrochromic materials (PTT, PDTT, PNT and PDNT) based on tetraphenylethylene (TPE) and triphenylamine (TPA) units by Stille coupling reaction were prepared. Electrochemical impedance spectroscopy (EIS) measurements found that four polymers had low resistance values which improved their electrochemical and electrochromic properties. In addition, the maximum coloration efficiency (CE; η) value is 126 cm2/C at 1246 nm of PDTT, bleaching and coloring response times are 2.6 s and 1.6 s, respectively. There is no significant change of performance after a 100 cycle scanning. In addition to their excellent electrochromic properties, they also exhibit a strong aggregation-induced emission (AIE) effect. Furthermore, the fluorescence color of PDNT changed from bright green to black when voltage was applied from 0.0 to 1.6 V. Four polymers responded rapidly to light and they maintained stability over a 1000 s cycle. Highlights • Novel multifunctional electrochromic materials have been synthesized and studied. • Polymers exhibit a strong aggregation-induced emission (AIE) effect. • Polymers exhibit excellent electrochromic and high electrofluorochromic properties. [ABSTRACT FROM AUTHOR]

Abstract A multifunctional integrated platform based on conjugated oligomers containing novel triarylamine (TAA) and fluorene units with responding to voltage, light and explosives stimuli and performing for sensors, detectors, memory media and high contrast displays was designed, and the stimuli-responsive mechanisms were studied. These oligomers show excellent thermal stability with no significant weight loss below 350 °C in nitrogen atmosphere. During the electrochemical reoxidation process, the oligomer films exhibit two pairs of obvious redox peaks with the strong color changes from yellowish of neutral state to green and blue of oxidized state, and remain good continuous cyclic stability over 500s with a cycle time of 10s. The electrofluorescent properties of the oligomers also can be tuned by electrochemistry redox, exhibiting high contrast. Meanwhile, non-volatile rewritable flash memory devices were produced with the sandwich structure ITO/oligomer/Al, which could gain the ON/OFF current ratio as high as about 104 at low threshold voltage of 1.2 V. Graphical abstract Image 1 Highlights • A multifunctional integrated platform with responding to voltage, light and explosives stimuli was designed. • The polymers exhibit good thermal stability, excellent electrochromic reversibility, high electrofluorescent contrast. • The polymers have high switching current ratio for memory device and fast response to TNT and TNP. [ABSTRACT FROM AUTHOR]

Abstract A series of alternate copolymers D‑ co ‑Ts named P(DPP‑TA) P(DPP‑Cz) and P(DPP‑DB) consisting of both diketopyrrolopyrrole (DPP) and different triarylamine (TAA) units, were synthesized by Stille cross-coupling reaction in which DPP acts as an acceptor and TAA acts as a donor. These D‑ co ‑Ts show good thermal stability in nitrogen (N 2) atmosphere. The solutions of D‑ co ‑Ts have strong UV–vis absorption bands in the range of 313 nm to 344 nm and have fluorescence (PL) peaks at from 415 nm to 496 nm with high quantum efficiency. The highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels and E g were combined with via cyclic voltammograms (CV) as −5.19 eV to −5.41 eV, −3.77 eV to −3.80 eV, and 1.42 eV to 1.62 eV, respectively. The P(DPP‑TA) film shows the evident color changes from original yellow to brownish to blue. New absorption peaks of P(DPP‑TA) appear at 412 nm and 938 nm with increasing voltage in the UV–vis spectrophotometer, indicating D‑ co ‑Ts can be promising electrochromic materials. The highest coloration efficiency reaches up to be 270 cm2 C−1 for the P(DPP‑Cz). The memory performances of the ITO/ polymer /Al sandwich devices were also studied, in which D‑ co ‑Ts exhibit the typical nonvolatile rewritable flash memory characteristics. The device of P(DPP‑DB) shows an ON/OFF current ratio of 5.80 × 104 under a threshold voltage of −1.80 V. Furthermore, in the explosive detection tests, the copolymer shows new emission band at 570 nm with addition of TNT, and the PL quenching efficiency goes up to be 82%. Graphical abstract Unlabelled Image Highlights • We take the strategy that DPP is chosen as acceptor groups and the TAA derivatives as donor groups to form alternate D-co-Ts polymers spaced by long flexible chain. • The highest coloration efficiency reaches up to be 270 cm2C-1 for the P(DPP-Cz). • The new alternate polymers have promising multifunctional application in the fields of electrochromic, photovoltage, memory device and explosive detection. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The polymer materials based on isoindigo, including electrochromic, memory device, explosive detection and photodetector. • The polymers show strong fluorescence with a fluorescence quantum efficiency (Ф PL) of up to 32.5%. • The polymers exhibit good thermal stability, high electrochromic coloration efficiency, high performance memory device and fast response to TNT and TNP. Abstract We report here that a series of novel donor-acceptor (D–A) conjugated polymers based on isoindigo were synthesized and characterized. As novel electrochromic materials, their optical and electrochemical properties have been investigated. Cyclic voltammograms (CV) of the polymer films exhibit two pairs of obvious redox peaks in the range of 0.76–1.80 V with strong color changes in the visible and near infrared (NIR) regions. The coloring and bleaching time are in the range of 3.5–4.9 s and 4.4–5.0 s, respectively. The amount of char yield at 800 °C in nitrogen for polymers was in the range of 56–64%. Especially, the polymers show strong fluorescence with a fluorescence quantum efficiency (Ф PL) of up to 32.5% which is reported firstly. In addition, memory properties, explosive detection and photoelectric properties for polymers are studied which indicating promising results. [ABSTRACT FROM AUTHOR]

Herein, five kinds of soluble electrochromic polyarylates were synthesized from the reaction of N,N'-bis(4-carboxyphenyl)-N,N'-di-2-naphthyl-1,4-phenylenediamine with five bisphenols via direct polycondensation process, respectively. These new materials showed no significant decomposition below 400 °C in nitrogen atmosphere. The maximum UV–vis absorption bands of these polyarylates located at 328–348 nm and 327–353 nm for solid films and DMSO solution, respectively. The polyarylate 6a , as an example, exhibited not only aggregation-induced emission (AIE) effect in different fraction tetrahydrofuran/water solution, but also solvatochromism in various polar solvents, markedly. Two reversible pairs of distinct redox peaks were associated with noticeable color changed from original colorless to yellowish orange and green for polymeric film could be observed in the cyclic voltammetry (CV) test. New absorption peaks emerged in near–infrared (NIR) region with increasing voltage in the UV–vis spectra, which indicates these polyarylates can be used as NIR electrochromic materials. These polyarylates performed high contrast of optical transmittance change around 42–53% with the highest coloration efficiency up to 236 cm 2 C −1 . [ABSTRACT FROM AUTHOR]

Herein, three kinds of electrochromic aromatic polyimides (PIs) were synthesized from 4,4′-diamino-4″-(quinolin-8-yloxy) triphenylamine (DAQTPA) with different dianhydrides, respectively. These PIs showed good thermostability below 450 °C even in air atmosphere. The maximum UV–vis absorption bands of PIs located at 321–338 nm for solid films. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the PIs were calculated from the cyclic voltammetry (CV) test as − 5.42 to − 5.44 eV and − 3.53 to − 3.85 eV, respectively. These PIs performed stable reversible electrochromic properties with optical transmittance change (ΔT) around 28–43% and coloration efficiency (η) around 74–117 cm 2 C − 1 . [ABSTRACT FROM AUTHOR]

A series of polymers, consisting both 2, 5-dithienylpyrrole (DTP) and different triarylamine units were synthesized by electrochemical oxidative polymerization. The structures of the monomers, including N-(4-(2,5-di(thiophen-2- yl) −1H-pyrrol-1-yl)phenyl)-N-Phenyl Naphthalene-2-amine (DTP-PNA), 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)-N,N-diphenylaniline (DTP-DPA), 4-(tert-butyl)-N-(4-(tert-butyl)phenyl)-N-(4-(2,5-di(thiophen-2-yl)-1H −pyrrol-1-yl)phenyl) aniline (DTP-TBPA), 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)-N-(4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)phenyl)-N-(p-tolyl)aniline (DTP-PTA-DTP), and N-(4-(9H-carbazol-9-yl)phenyl)-4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)-N-(4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)phenyl)aniline (DTP-CPA-DTP) were elucidated by FT-IR, 1 H NMR, 13 C NMR, Mass spectra (MS) and the performance and morphology of resulting polymers (P(DTP-PNA), P(DTP-DPA), P(DTP-TBPA), P(DTP-PTA-DTP), and P(DTP-CPA-DTP)) were determined by cyclic voltammetry (CV), ultra-visible-near infrared (UV–Vis–NIR) spectrophotometer, and scanning electron microscopy (SEM), respectively. The polymers exhibit good reversible multicolor in the visible and NIR region (original yellowish to dusty blue until violet occurred), with better coloration efficiency (CE), fast response time. [ABSTRACT FROM AUTHOR]

A series of Schiff bases (SBs) were designed and prepared from 2-thiophenecarboxaldehyde and different triphenylamine (TPA) derivatives. The structures of the compounds were characterized by Fourier transform infrared (FT-IR), hydrogen nuclear magnetic resonance ( 1 H NMR). The optical and electrochemical properties were tested by ultraviolet–visible (UV–vis) spectroscopy and cyclic voltammetry (CV) techniques. The SBs exhibited stable and reversible electrochromic properties. Furthermore, multiple reversible colors states were also observed with the change of pH. Consequently, the SBs can be used as electrochromic and acidochromic materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • 3D structure with sufficient space for ion avoids expansion and degradation. • Mixed valence blocks improve the stability of ion radicals and cycle stability. • TPAF-CA PL is used for the detection of explosive TNP with high sensitivity. • PAs with multicolor has high optical contrast, fast response, long-term cycle. Near-infrared electrochromic (NIR EC) functional materials are attracting increasing attention owing to their great potential for applications in smart window. However, obtaining high performance NIR EC material with high optical transmittance contrast, fast redox switching and long-term cyclic stability is still a challenge. Introducing four triphenylamine (TPA) units into one planar fluorene core to build robust three dimensional (3D) framework which not only makes ion and electron move freely but also provides sufficient space and storage sites for hosting ions will meet the requirement. Here, three kinds of new polyamides (PAs) based on conjugated fluorene as the bridge unit were designed and polycondensized by a new diamine N, N'-(9,9-bis(4-(diphenylamino)phenyl)-9H-fluorene-2,7-diyl)-bis(N-(4-methoxyphenyl) benzene-1,4-diamine), with three kinds of dicarboxylic acids to form TPAF-6F, TPAF-CA and TPAF-OA. The obtained new PAs exhibit impressive solution-processability and excellent thermal stability. Cyclic voltammograms (CV) and differential pulse voltammograms (DPV) of the PAs imply strong electronic coupling within molecule. Furthermore, the TPAF-OA film exhibits excellent EC performance with multi-coloured EC behaviour, high optical contrast (92%), high coloration efficiency (203 cm2 C−1) and outstanding cycle stability (optical contrast remains 90% over 1400 cycles) in the NIR range. TPAF-CA also shows impressive fluorescence (PL) quantum efficiency which could be used as sensor for explosive and nonvolatile flash memory properties. The strategy of introducing 3D framework block into polymer will pave a way for fabricating high performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

Electrochromic (EC) materials have captured intense attentions in the field of smart window, label screen and camouflage recently. The structure of EC active group is crucial to the properties of product. In this study, novel PAs with EC and memory properties were developed by polycondensation of asymmetry triarylamine N, N ' -bis(4-aminophenyl)-N-isopropyl-N ' -phenylbenzene-1,4-diamine (IPATAA) with five different dicarboxylic monomers. An isopropyl group of the IPATAA molecule is linked to a nitrogen atom to increase electron density and solubility. Furthermore, PAs are apt to be processed into a film by spin-coating or printing. After electro-oxidation, PAs films change from colorless to blue. The coloring time and bleaching time is 2.8–4.1 s and 2.6–4.5 s, respectively. The highest coloring efficiency of PAs film is 366 cm2 C−1. Memory devices made using the PAs show non-volatile memory characteristics such as lower switching threshold voltages (<1.08 V) and better switching current ratios (>2 × 104). [Display omitted] • A new asymmetric IPATAA monomer was designed and synthesized. • Coupling between benzene rings in different backbone was occurred due to strong electron donor ability of isopropyl group. • The PAs show high ΔT of 53.5% with the CE of 366 cm2 C−1. And starting voltage of memory device is as low as 1.08 V. [ABSTRACT FROM AUTHOR]

A series of new polyamides (PAs) were designed and synthesized based on two novel triarylamines (TAA) with fused ring groups via phenyl bridge through the Suzuki coupling reaction. These novel PAs have amorphous structure and excellent thermal stability, with a carbon residue rate of up to 70% at 800 °C in nitrogen atmosphere. In the process of electrochemical oxidation, there is no obvious recessionary in current and transmittance over 1000s with a cycle time of 10s, which showing high contrast and excellent cycle stability. And the electrofluorochromic (EFC) performance can also be adjusted by being applied voltage. 1NAT-CA and 9AAT-CA have solvatochromic effect in absorption, fluorescence (PL) in solvents, 1NAT-6F and 1NAT-BA have aggregation-induced emission enhancement (AIEE) properties in solid state. The kind of multifunctional integrated PAs show characteristics of responding to voltage, explosive and hazardous gas stimuli and the stimuli-responsive mechanisms are investigated, which have the prospect of application in photoelectric sensors, explosive detectors and high-contrast displays. Image 1 • Triphenylamine-based polyamides (PAs) containing fused ring groups were prepared. • PAs exhibite excellent electrochemical cycling stability and adjustable electroluminescent properties. • PAs have theAIEE effect, solvatochromic effect and can be used as sensors for TNP and HCl. [ABSTRACT FROM AUTHOR]

The display devices of the future will tend to be multifunctional, and the dual-mode device for emission and coloration satisfies the requirements of practical applications. We synthesized materials with electrochromic (EC) and electrofluorochromic (EFC) properties through the combination of triarylamine (TAA) and ladder-like polysilsesquioxanes (LPSQs). The ladder-like structure was confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and 29Si-NMR techniques. These polymers exhibit up to 37.3% fluorescence (PL) quantum efficiency (Ф PL) and show strong solid-state fluorescence because TAA groups are effectively isolated in ladder-like backbone in LPSQs. The TAA-LPSQs films exhibit reversible change from colorless of bleached state to blue or green of oxidized state. Among them, the optical contrast of the MPA-LPSQ film synthesized from 1-(4-(bis(4-methoxyphenyl)amino)phenyl)-3-(3-(triethoxysilyl)propyl)urea is as high as 83.0% at 787 nm, which shows excellent cycle stability over 1000 s. Unique structure and good electrochemical activity of TAA-LPSQs make them promising materials for dual-mode device. The EC/EFC device (ECD/EFCD) was assembled using MPA-LPSQ as an active layer which showed good performance. In addition, TAA-LPSQs exhibit excellent sensitivity to 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) detection, so these materials can also be applied as highly sensitive chemosensor for explosives. Image 1 • Ladder-like polysilsesquioxanes with side chain triarylamines were synthesized. • MPA-LPSQ film exhibited 83.0% optical contrast at 787 nm. • The polymers show simultaneous electrochromic, electrofluorochromic. [ABSTRACT FROM AUTHOR]

Four novel materials containing isoindigo derivatives were synthesized via Stille coupling reaction. These polymers not only have excellent electrochromic properties (the highest electrochromic efficiency reaches 195 cm2 C−1), but also have low charge transfer resistance (R ct). The range of switching threshold is from −1.7 V to −4.0 V and the current ratio of the device beyond 10−5 for memory device. Moreover, the polymers can also be used as explosive detector. A sharp drop in the fluorescence intensity of the polymer appeared when trinitrotoluene (TNT) or 2, 4, 6-trinitrophenol (TNP) was added. • Multifunctional polymers for electrochromic, resistance memory, and detector devices have been synthesized and studied. • Polymers exhibit good thermal stability, excellent electrochemical properties. • Polymers have high electrochromic coloration efficiency and low charge transfer resistance. [ABSTRACT FROM AUTHOR]