Electrochromic polymers (ECPs) have great application potential in flexible displays, and there is an increasing expectation of using green methods to form ECP films. Herein, we propose a modified microemulsion method to prepare Cyan/Magenta/Yellow (C/M/Y) water-dispersed electrochromic polymer nanoparticles systems. Three polymer films (WDECP-C/M/Y) maintain similar electrochemical properties compared to their corresponding organic solvent-based polymer films. It is intriguing that WDECP-C/M/Y exhibit better electrochromic properties in terms of higher cycling stability (97.24%, 95.05%, and 52.84%, respectively) and faster switching time (0.94 s, 1.09 s, and 1.34 s for coloring time, respectively) due to the introduction of nanoparticles. In addition, it can achieve various desired colors by blending the C/M/Y water-dispersed electrochromic polymer nanoparticles systems in different ratios. The calculated chromaticity coordinates of the blending polymer films show close values to the experimental observation, and the calculated ΔE*ab values range from 2.6 to 10.3, which may provide theoretical guidance for precisely color control. Finally, large-scale and patterned devices were assembled, which can achieve colored-to-colorless reversible electrochromism at a low driving voltage of 0 to 1.5 V. This work puts forward a universal and environmentally sustainable strategy to prepare water-dispersed electrochromic polymer nanoparticles systems, demonstrating their wide range of applications in display devices and electronic tags.
The systematic study of two ionic porous organic polymers (iPOPs) based on viologens and their first applications in the electrochromic field are reported. The viologen-based iPOPs are synthesized by electrochemical polymerization with cyano groups, providing a simple and controllable method for iPOPs that solves the film preparation problems common to viologens. After the characterization of these iPOPs, a detailed study of their electrochromic properties is conducted. The iPOP films based on viologens structure exhibit excellent electrochromic properties. In addition, the resulting iPOP films show high sensitivity to electrolyte ions of different sizes in the redox process. Electrochemical and electrochromic data of the iPOPs explain this phenomenon in detail. These results demonstrate that iPOPs of this type are ideal candidates as electrochromic materials due to their inherent porous structures and ion-rich properties.
The integration of an electrochromic (EC), energy storage, and adaptive camouflage system into a multifunctional electronic device is highly desirable and yet challenging. In this work, two carbazole-based conjugated polymers were prepared to achieve a reversible color change from transparent to yellow, green, and blue-green by easy electrochemical polymerization. Due to its dendritic geometry, the conjugated polymer p3CBCB exhibits a loosely packed structure with a relatively higher specific surface area than pCBCB, as well as a relatively better ionic conductivity. The kinetic and galvanostatic charge-discharge (GCD) study reveals that p3CBCB has superior properties with larger optical contrast and volumetric capacitance. Moreover, EC supercapacitors (ECSCs) are constructed with p3CBCB as the EC layer and ZnO@PEDOT:PSS as the ion storage layer. The dual function of a ZnO interface layer on improvement in reflectivity contrast (ΔR% > 35.1%) and cycling stability (over 40,000 cycles) using ZnO as a reflective and protective layer is demonstrated in an ion storage layer. Additionally, patterned prototype devices based on the design of double-sided ITO glass were successfully assembled, which can simulate conditions of various natural environments including forests, wilderness, and deserts. This study provides new ideas not only for the preparation of conjugated polymers that can simultaneously realize reversible transparent-yellow-green conversion but also for the achievement of high coloration efficiency, high reflectivity contrast, and good stability of ECSCs for adaptive camouflage.
This work presents a new strategy to achieve a truly black electrochromic film and develop available intelligent eye-protection filters with "day mode" and "night mode", promising to minimize the harmful effects of light on eyes. The soluble red-to-transparent electrochromic polymer P1 was constructed using quinacridone as the basic unit and introduced dual-donor proDOT and DTC units with similar electron-donating capabilities. The beneficial broader absorption associated with the dual-donor in P1 results in ideal spectrum complementarity with P2 (cyan-to-transparent) in the visible region (380-780 nm). In addition to complementary colors, both polymers exhibit good compatibility with respect to electrochemical and electrochromic properties. Therefore, a P1/P2 film with a mass ratio of 1:1.5 for blending is preferred to obtain truly black color with fast switching time and good cyclic stability. Furthermore, an electrochromic device for intelligent eye-protection filters was designed and assembled with the P1/P2 film as the electrochromic layer and P3 featuring a yellow (antiblue ray)-to-dark gray color change as the ion storage layer. The assembled prototype electrochromic device demonstrated promising applications in intelligent day-night optical adjustment for eye-protection filters.
Electrochromic polymer film preparation methods such as spin coating, spray coating, and electrochemical polymerization, are commonly used. At present, developing new film preparation technology is an important aspect in the field of electrochromics. Herein, a continuous in situ self-growing method based on the chemical reaction occurring on the surface of an ITO glass between a metal oxide and organic acid groups was successfully applied to prepare electrochromic polymer films at a mild room temperature. SEM, FT-IR spectroscopy, XPS, and XRD characterization methods were combined to reveal the process and mechanism of film formation. The following notable electrochromic properties were observed: switching time within 6 s, contrast reached 35%, and minimal decrease of stability after 600 cycles. Finally, the patterned films were obtained through the directional growth of polymers in solution. This study provides an effective strategy for designing and preparing electrochromic films by self-growing methods in future applications.
This work presents a new strategy to achieve highly stable electrochromic devices and bilayer film construction. A novel solution-processable electrochromic polymer P1-Boc with quinacridone as the conjugated backbone and t-Boc as N-substituted non-conjugated solubilizing groups is designed. Thermal annealing of P1-Boc film results in the cleavage of t-Boc groups and the formation of NâHâ¯OâC hydrogen-bonding crosslinked network, which changes its intrinsic solubility characteristics into a solvent-resistant P1 film. This film retains the electrochemical behavior and spectroelectrochemistry properties of the original P1-Boc film. Intriguingly, the electrochromic device based on the P1 film exhibits an ultrafast switching time (0.56/0.80 s at 523 nm) and robust electrochromic stability (retaining 88.4% of the initial optical contrast after 100 000 cycles). The observed cycle lifetime is one of the highest reported for all-organic electrochromic devices. In addition, a black-transparent bilayer electrochromic film P1/P2 is developed in which the use of the solvent-resistant P1 film as the bottom layer avoids interface erosion of the solution-processable polymer in a multilayer stacking.
Programmed death-ligand 1 (PD-L1) ensures that tumor cells escape T-cell-mediated tumor immune surveillance. However, gliomas are characteristic of the low immune response and high-resistance therapy, it is necessary to understand molecular regulatory mechanisms in glioblastoma, especially the limited regulation of PD-L1 expression. Herein, we show that low expression of AP-2α is correlated with high expression of PD-L1 in high-grade glioma tissues. AP-2α binds directly to the promoter of the CD274 gene, not only inhibits the transcriptional activity of PD-L1 but enhances endocytosis and degradation of PD-L1 proteins. Overexpression of AP-2α in gliomas enhances CD8+ T cell-mediated proliferation, effector cytokine secretion, and cytotoxicity in vitro. Tfap2a could increase the cytotoxic effect of Cd8+ T cells in CT26, B16F10, and GL261 tumor-immune models, improve anti-tumor immunity, and promote the efficacy of anti-PD-1 therapy. Finally, the EZH2/H3K27Me3/DNMT1 complex mediates the methylation modification of AP-2α gene and maintains low expression of AP-2α in gliomas. 5-Aza-dC (Decitabine) treatment combines with anti-PD-1 immunotherapy to efficiently suppress the progression of GL261 gliomas. Overall, these data support a mechanism of epigenetic modification of AP-2α that contributes to tumor immune evasion, and reactivation of AP-2α synergizes with anti-PD-1 antibodies to increase antitumor efficacy, which may be a broadly applicable strategy in solid tumors.
CD8-Positive T-Lymphocytes , DNA Modification Methylases , Glioma , Transcription Factor AP-2 , Humans , B7-H1 Antigen/metabolism , CD8-Positive T-Lymphocytes/metabolism , Cell Line, Tumor , Glioma/genetics , Glioma/metabolism , Immune Evasion , Transcription Factor AP-2/genetics , DNA Modification Methylases/metabolism
The study of piezochromic materials (PCMs) has become an attractive field and numerous scholars have reported various material structures and phenomena. PCMs incorporating near-infrared (NIR) emission have led to a broader range of applications due to the strong penetration and interference resistance of longer wavelength light sources. However, NIR PCMs are still rare due to difficulties in tuning molecular configuration, conformation and stacking structure. In this review, organic compounds are classified according to their types and structures, and recent advances in NIR PCMs are comprehensively summarized and described. The various factors affecting the piezochromic properties from the perspective of the compound structure are shown. The effects of pressure on the photophysical changes of different compounds are discussed. It is expected to provide ideas for subsequent NIR PCMs, from structural design to predicting their photophysical properties under pressure.
Catheter-associated urinary tract infections are one of the most common hospital-acquired infections. Encrustation formation results from infection of urease-producing bacteria and further complicates the situation. A typical sign of the initial onset of encrustation formation is the alkalization of the urine (pH up to 9-10). However, effective antibacterial strategies with high antimicrobial loading efficiency and pH-responsiveness of antimicrobial release are still lacking. In this study, we developed a poly(sulfobetaine methacrylate)-tannic acid (polySBMA-TA) hydrogel coating, which served as a universal, efficient, and responsive carrier for antimicrobials on urinary catheters. Common antimicrobials, including poly(vinylpyrrolidone)-iodine, copper ions, and nitrofurazone were loaded into the polySBMA-TA coating in high efficiency (several fold higher than that of the polySBMA coating), via the formation of multiple non-covalent interactions between the antimicrobials and hydrogel coating. The hydrogel coatings maintained good antibacterial properties under neutral conditions. More importantly, the pH-responsive release of antibacterial agents under alkaline conditions further enhanced the antibacterial activity of the coatings, which was advantageous for killing the urease-producing bacteria and preventing encrustation. In vitro and in vivo tests confirmed that the hydrogel coating has good biocompatibility, and could effectively inhibit bacterial colonization and encrustation formation. This study offers new opportunities for the utilization of a simple and universal antimicrobial-loaded hydrogel coating with smart pH-responsive properties to combat bacterial colonization and encrustation formation in urinary catheters.
Anti-Infective Agents , Urinary Catheters , Urinary Catheters/microbiology , Hydrogels , Urease , Biofilms , Anti-Infective Agents/pharmacology , Anti-Bacterial Agents/pharmacology , Bacteria , Hydrogen-Ion Concentration
The composite or hybrid of organic and inorganic materials is one of the common ways to improve the properties of photoelectric functional materials. Perylene bisimide (PBI) derivatives, as large π-conjugated organic small molecules, are a class of photoelectric functional materials with excellent performance. However, there were few reports on PBIs in the electrochromic field due to the difficulty of film-forming caused by their generally poor solubility. Here, water-soluble PBI derivatives (PDI-COOH and PCl-COOH) were synthesized. The hybrid films (ZnO@PDI-COOH/PCl-COOH) formed by the coordination bond and π-π stacking were prepared via a simple solution immersion method. Fourier transform infrared spectrometry and X-ray diffraction as well as scanning electron microscopy, and energy-dispersive spectrometry results further confirmed the formation of hybrid films. At the same time, electrochemical and spectroelectrochemical analyses revealed that the films have reversible redox activity and cathodic electrochromic properties, which can change from orange-red to purple. The ZnO@PDI-COOH hybrid film formed by coordination bonds exhibits fast switching times (1.7 s colored time and 2.6 s bleached time), good stability (retain 92.41% contrast after 2400 cycles), a low driving voltage (-0.6-0 V), and a high coloration efficiency (276.14 cm2/C). The corresponding electrochromic devices also have good electrochromic properties. On this basis, a large-area (100 mm × 100 mm) electrochromic display device with fine patterning was fabricated by using the hybrid film, and the device shows excellent reversible electrochromic performance. This idea of constructing organic-inorganic hybrid materials with coordination bonds provides an effective, energy-saving, and green method, which is expected to promote the large-scale and fine production of electrochromic materials.
Organic single crystals (OSCs) with excellent flexibility and unique optical properties are of great importance due to their broad applicability in optical/optoelectronic devices and sensors. Nevertheless, fabricating flexible OSCs with room-temperature phosphorescence (RTP) remains a great challenge. Herein, we propose a host-guest doping strategy to achieve both RTP and flexibility of OSCs. The single-stranded crystal is highly bendable upon external force application and can immediately return to its original straight shape after removal of the stress, impressively emitting bright deep-red phosphorescence. The theoretical and experimental results demonstrate that the bright RTP arises from Förster resonance energy transfer (FRET) from the triphenylene molecules to the dopants. This strategy is both conceptually and synthetically simple and offers a universal approach for the preparation of flexible OSCs with RTP.
Preparing conjugated polymer films via interfacial Suzuki polymerization is a promising method for obtaining desirable electrochromic materials with desired structures. Here, a series of aryl boronic esters and triphenylamine-based aryl bromides were applied as precursors, and several polymer films were finally obtained via the liquid/liquid interfacial Suzuki polymerization reaction under mild conditions. FT-IR, UV, and Raman as well as electrochemistry, SEM, and EDS results all provide strong evidence for the formation of the desired polymer structures. Among them, the TPA-Wu (containing triphenylamine and alkyl-fluorene) film exhibits the best film-forming quality. Besides, these polymer films were applied in electrochromic applications. The results show that electrochromic properties can be affected by the quality of film formation. It is worth mentioning that the TPA-Wu film could achieve excellent electrochromic properties with reversible multicolor changes from transparent yellow to orange-red to blue-green under varying potentials. Compared to other triphenylamine-based electrochromic materials, the TPA-Wu film possessed the most desirable coloring efficiency, higher optical contrast, and shorter switching time. This work provides an existing general approach of liquid/liquid interfacial Suzuki polymerization for constructing conjugated polymer films toward electrochromic applications.
Copper phthalocyanine (CuPc) films with different morphologies were electrodeposited on the surfaces of ITO electrodes. Then, in each case, a polyaniline (PANI) film was electrochemically polymerized in situ on the surface of the copper phthalocyanine film to form a CuPc-PANI composite film. The electrochemical properties of the CuPc-PANI composite film were observed to be much better than those of the film without CuPc. With the modification involving the CuPc nanowires, the composite film formed a finer particle surface and an increased interface area between the PANI and the electrolyte. Compared to the single-component PANI film, the CuPc-PANI composite film exhibited better performance with a higher optical contrast (58% at 730 nm), a faster response speed (coloring time of 1.02 s, discoloring time of 1.96 s), and better cycling stability (68.71% of the initial electrochemical activity after 500 cycles, in contrast to only about 48.02% for PANI). Moreover, the CuPc-PANI film shows a new feature that can be used as a supercapacitor (specifically a capacitance value of about 5.4 mF cm-2 at typical currents). Our results demonstrate that the prepared CuPc-PANI composite film is one of the best candidates for multiple potential applications such as high-performance polymer electrochromic materials and supercapacitors.
A novel triphenylamine derivative-linked ionic liquid unit, 1-(6-((4-(bis(4-(thiophen-2-yl)phenyl)amino)benzoyl)oxy)hexyl)-3-methyl-imidazolium tetrafluoroborate (TTPAC6IL-BF4), was designed and synthesized successfully, and its corresponding polymer PTTPAC6IL-BF4 was obtained by the electropolymerization method. The highest occupied molecular orbital energy band of TTPAC6IL-BF4 is higher and the onset oxidative potential lower compared with that of 6-bromohexyl 4-(bis(4-(thiophen-2-yl)phenyl)amino) benzoate (TTPAC6Br) without modifying the ionic liquid unit. Both PTTPAC6IL-BF4 and PTTPAC6Br show similar color change and optical contrast under different redox states. However, PTTPAC6IL-BF4 presents a faster electrochromic switching time than PTTPAC6Br owing to the improved ionic conductivity and ion diffusion coefficient with the introduction of a pendent ionic liquid unit. It is more intriguing that PTTPAC6IL-BF4 could show electrochromism under different potentials even without supplying any additional electrolyte. The particular behavior further proves that BF4- ions around imidazole cations at the side chain may participate in balancing the charge of the polymer backbone when redox reaction happens, resulting in faster movement of ions during the doping process. The results imply that introducing an ionic liquid unit to the side chain is an efficient method to improve the switching time of conjugated polymers and would be inspirational for the design and preparation of novel bifunctional electrochromic polymeric electrolytes.
A star-shaped thiophene derivative, namely PHBT, consisting of one central core of phenyl and three arms of bithiophene, was newly synthesized and characterized, in order to further investigate the relationship between the star-shaped monomer structure (central core and peripheral arm) and the polymeric electrochromic properties. Then it was further successfully prepared into the corresponding cross-linked polymer pPHBT via electrochemical polymerization. After applying positive voltage, pPHBT exhibited excellent electrochromic properties with surprising multi-color changes between three colors, orange-yellow, green and blue, and a fast color switching speed. Furthermore, electronic structure, cyclic voltammetry and electrochromic results of pPHBT can contribute much to explain the electrochromic behavior of pTPABT with the triphenylamine core and the quadruple thiophene arm. The electrochromism of pTPABT might consist of two parts derived from the oxidative states of triphenylamine and quadruple thiophene groups, respectively. This offers a new insight into the electrochromism mechanics of conjugated polymers.
A novel strategy to obtain rapid electrochromic switching response by introducing 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) moiety into polytriphenylamine backbone has been developed. The electrochromic properties of the integrated polymer film are investigated and a possible mechanism is proposed with TEMPO as a counterion-reservoir group to rapidly balance the charges during electrochromic switching, which leads to significantly improved electrochromism performance.
The asymmetric unit of the mononuclear title complex, [NiBr2(C3H8O)4], comprises a Ni(II) cation located on a centre of inversion, one Br(-) anion and two propan-2-ol ligands. The Ni(II) cation exhibits a distorted trans-Br2O4 environment. There are O-Hâ¯Br hydrogen bonds connecting neighbouring mol-ecules into rows along [100]. These rows are arranged in a distorted hexa-gonal packing and are held together by van der Waals forces only.
Cyanostilbene derivatives with the aggregation-induced emission enhancement (AIEE) activity are prepared by Knoevenagel and Suzuki reactions. Among them, the dye (Z)-2,3-bis(4'-(diphenylamino)-[1,1'-biphenyl]-4-yl)acrylonitrile (CNS-4) nanoparticle suspension shows the polarity-dependent characteristics of the fluorescence properties. By the fluorescence spectroscopy and transmission electron microscopy (TEM) analysis, the restriction of transfer from the local excited (LE) state to the intramolecular charge-transfer (ICT) state and crystal formation results in a blue-shift in emission and enhances the intensity in the aggregate state. Additionally, the luminophors CNS-3 and CNS-4 possess the AIEE effect as well as mechanochromic fluorescent properties. This mechanofluorochromic behavior originates from the change between the crystalline and the amorphous state.
Well-defined one-dimensional (1D) perylene-diimide derivative (PDD) nanowire arrays were prepared via a simple electrophoretic deposition method by using anodic aluminum oxide (AAO) templates. The morphology of the as-deposited films was characterized by field emission scanning electron microscope and transmission electron microscopy. The highly ordered nanoarrays were free-standing after removing the AAO supports. Further studies revealed that the growth process of the nanowires in the AAO pores followed a 'bottom-up' growth model. A photoreceptor with PDD nanowire arrays as the charge generation layer was fabricated. It exhibited a better photoconductivity under light illumination when compared to that of its bulk counterpart. Our results suggested that electron-accepting PDD nanowire arrays can be used as a potential candidate for photoconduction devices, which would facilitate further exploration of new technological applications of the photoimaging process.
