Spectroelectrochemical Studies Research Articles

Thieno[3,2-b]thiophene Incorporated Redox Active 22π and 34π Core-Modified Expanded Isophlorinoids.

Incorporation of a thieno[3,2-b]thiophene into an isophlorinoid-like framework alters the aromaticity by extending the macrocyclic π-circuit. Their opto-electronic and aromatic properties significantly differ from other 22π and 34π porphyrinoids. Among the three different 34π hexaphyrins, furan based hexaphyrin adopts a non-aromatic 'figure-of-eight' conformation. Replacing all the furans either by thiophene or selenophene induces a planar conformation with aromatic characteristics. Spectro-electrochemical studies revealed reversible two-electron ring oxidation to yield their 4np dicationic species respectively.

Spectroelectrochemical study of carbon structural and functionality characteristics on vanadium redox reactions for flow batteries.

Vanadium redox flow batteries have applications for large-scale electricity storage. This paper reports the influence of carbon structural characteristics of sustainable walnut shell-derived carbons in carbon/polyvinylidene fluoride composite electrodes on vanadium redox reactions. Pyrolysis, gasification, and chemical treatment procedures were used to modify the structural characteristics of carbons. Carbon functional groups were modified by chemical treatment with HNO3, heat treatment with K2CO3, and high-temperature NH3 treatment. Carbon porous structures were characterized using gas adsorption studies. Raman spectroscopy and X-ray diffraction were used to characterize the carbon molecular structure. Functional groups were characterized using X-ray photoelectron spectroscopy, acid/base titrations, temperature-programmed desorption, and Fourier transform infrared spectroscopy. The influence of carbon structure, porosity, and surface functional groups on the redox reactions of vanadium was investigated using cyclic voltammetry and electrical impedance spectroscopy. The VO2+/VO2 + and V2+/V3+ couples had well-defined peaks in cyclic voltammetry, with the former being the most intense, but the V3+/VO2+ couple was not observed for samples carbonized under nitrogen. The results show that V2+/V3+ and VO2+/VO2 + couples observed in cyclic voltammograms were enhanced for carbonization temperatures up to 800 °C. Electrical impedance spectroscopy also showed impedance trends. The electrochemistry results are primarily related to changes in carbon structure and the catalysis of V3+ oxidation by surface functional groups in the carbon structure. The V3+/VO2+ couple was limited by slow kinetics, but it occurs on specific oxygen and nitrogen sites in the carbon structure. The oxidation of V(iii) to V(iv) only occurs on a limited number of surface sites, and the outer-sphere electron transfer to oxidize V(iii) takes place at much more positive potentials. The coulombic, voltage, and energy efficiency of the carbon electrodes were suitable for batteries.

Spectroelectrochemical studies of TDMQ20: A potential drug against Alzheimer’s disease

Alzheimer’s Disease (AD), reported for the first time in 1906, is a common disease that remains incurable to this day. In the past, a family of treatments using Cu(II) chelators failed during clinical trials, evidencing the importance of pre-clinical studies. In this work, we performed electrochemical characterisation of TDMQ20, a new potential drug against AD, using electrochemistry and spectroelectrochemistry. On the basis of voltammetry, we determined that TDMQ20 undergoes a two-step irreversible oxidation process and a one-step irreversible reduction process. Both oxidation and reduction reactions are pH-sensitive. Bidimensional UV–Vis spectroelectrochemistry (UV–Vis-SEC) allowed us to confirm that oxidation of TDMQ20 can occur both on the aliphatic chain and on the aromatic ring. The results expand the knowledge of the TDMQ20 redox activity in the human body which is important from the point of view of the toxicity of the proposed therapy.

Exploring the synergistically enhanced activity of novel α-MnSe/ppy composite for superior OER catalyst in alkaline medium

The extremely slow kinetics of the water-splitting process stymies the synthesis of hydrogen (H2) from water. To comprehend the main obstacle to the oxygen evolution reaction (OER), it is also necessary to enhance the development of efficient OER electrocatalysts. In this work, manganese selenide with polypyrrole heterostructure is synthesized, described, and electrochemically assessed as an effectiveelectrocatalystfor OER. The novel synthesized materialis characterizedusing a variety of techniques, including scanning electron microscopy (SEM), powder x-ray diffraction (PXRD), transmission electron microscopy (TEM) etc. The unique α-MnSe/ppy composite catalyst is shown to be exceedingly efficient, starting the OER at an astoundingly low voltage of 168 mV (vs. reversible hydrogen electrode [RHE]) at 10 mA cm−2, with a tafel slope of 67 mV dec-1. Also, operando UV–Vis spectro-electrochemical studies give an insight towards the intermediate species formed during the OER catalysis. Under similar electrochemical conditions, the α-MnSe/ppy electrocatalyst outperforms its α-MnSe and ppy counterparts for OER in an aqueous KOH (1.0 M) solution. These results surpass benchmark electrocatalysts made of Mn and rare earth metals. With this invention, a desired non-noble metal is made available that works excellently as an OER electrocatalyst.

Orthogonal Electrochemical Stability of Bulk and Surface in Lead Halide Perovskite Thin Films and Nanocrystals.

Lead halide perovskites have attracted significant attention for their wide-ranging applications in optoelectronic devices. A ubiquitous element in these applications is that charging of the perovskite is involved, which can trigger electrochemical degradation reactions. Understanding the underlying factors governing these degradation processes is crucial for improving the stability of perovskite-based devices. For bulk semiconductors, the electrochemical decomposition potentials depend on the stabilization of atoms in the lattice-a parameter linked to the material's solubility. For perovskite nanocrystals (NCs), electrochemical surface reactions are strongly influenced by the binding equilibrium of passivating ligands. Here, we report a spectro-electrochemical study on CsPbBr3 NCs and bulk thin films in contact with various electrolytes, aimed at understanding the factors that control cathodic degradation. These measurements reveal that the cathodic decomposition of NCs is primarily determined by the solubility of surface ligands, with diminished cathodic degradation for NCs in high-polarity electrolyte solvents where ligand solubilities are lower. However, the solubility of the surface ligands and bulk lattice of NCs are orthogonal, such that no electrolyte could be identified where both the surface and bulk are stabilized against cathodic decomposition. This poses inherent challenges for electrochemical applications: (i) The electrochemical stability window of CsPbBr3 NCs is constrained by the reduction potential of dissolved Pb2+ complexes, and (ii) cathodic decomposition occurs well before the conduction band can be populated with electrons. Our findings provide insights to enhance the electrochemical stability of perovskite thin films and NCs, emphasizing the importance of a combined selection of surface passivation and electrolyte.

In situ spectroelectrochemical and nanomechanical studies in the atomic force microscopy mode of the oxidation—reduction processes of poly-N,N′-ethylenebis(3-methoxysalicylideneimine)

In situ spectroelectrochemical and nanomechanical studies in the atomic force microscopy mode of the oxidation—reduction processes of poly-N,N′-ethylenebis(3-methoxysalicylideneimine)

Electronic Coupling in Triferrocenylpnictogens.

From a fundamental perspective, studies of novel mixed-valent complexes containing ferrocenyl units are motivated by the prospect of improving and extending electron transfer models and theories. Here, the series of triferrocenylpnictogens Fc3E was extended to the heavier analogues (E = As, Sb, and Bi), and the influence of the bridging atom was investigated with Fc3P as a reference. Electrochemical studies elucidate the effect of electrostatic contribution on the large redox splitting (ΔE 1) exhibited by the compounds and solvent stabilization in the case of Fc3As. Structural characterization of the triferrocenylpnictogens combined with spectroelectrochemical studies indicates weak electronic couplings in the related cations [Fc3E]+, suggesting a through-space mechanism.

Symmetry Breaking Charge Separation in Far-Red Absorbing Bisstyryl-Bodipy Dimers

Symmetry breaking charge transfer is one of the important photo-events occurring in photosynthetic reaction centers that is responsible for initiating electron transfer leading to a long-lived charge-separated state and has been successfully employed in light-to-electricity converting optoelectronic devices. Here, we report the synthesis of far-red absorbing and emitting BODIPY-dimer to undergo symmetry-breaking charge transfer leading to charge-separated states of appreciable lifetimes in polar solvents. Compared to its monomer analog, both steady-state and time-resolved fluorescence originating from the S1 state of the dimer revealed quenching which increased with an increase in solvent polarity. The electrostatic potential map from DFT and the time-dependent DFT calculations suggested the existence of a quadrupolar type charge transfer state in polar solvents, and the singlet excited state to be involved in the charge separation process. The electrochemically determined redox gap to be smaller than the energy of the S1 state supporting thermodynamic feasibility of the envisioned symmetry-breaking charge transfer and separation. The spectrum of the charge-separated state arrived from spectroelectrochemical studies, revealing diagnostic peaks helpful for transient spectral interpretation. Finally, ultrafast transient pump-probe spectroscopy provided conclusive evidence of diabatic charge separation in polar solvents by far-red pulsed laser light irradiation. The measured lifetime of the final charge-separated states was found to be 165 ps in dichlorobenzene, 140 ps in benzonitrile, and 43 ps in dimethyl sulfoxide, revealing their significance in light energy harvesting, especially from the less-explored far-red region.

Evaluating Zn ferrite (ZnxFe3-xO4; 0 ≤ x ≤ 1) for alkaline water oxidation: electrochemical and spectro-electrochemical study

Evaluating Zn ferrite (ZnxFe3-xO4; 0 ≤ x ≤ 1) for alkaline water oxidation: electrochemical and spectro-electrochemical study

In-situ spectroelectrochemical analysis: Irreversible deformation of cesium lead bromide Perovskite Quantum Dots in SiOx matrices

To practically utilized the organometallic lead halide perovskites to optoelectronic devices and photoelectrochemical cells, numerous efforts have been utilized to obtain the perovskites with low-energy process with coverage of various inorganic mediums to improve stability against humidity. By utilizing ligand-assisted reprecipitation process, under ambient condition at room temperature, the dimensionally confined perovskite quantum dots in silica matrices (PQD@SiOx) were obtained, and they were stable under several months under the ambient condition. To apply the PQD@SiOx to the photoelectrochemical cells by introducing direct contact between PQD@SiOx and electrolyte, the material/photophysical properties under electrochemical conditions are necessary to be studied. However, the role of silica coverage to the electrochemical behaviors of the PQD cores in the silica medium were not yet studied. In this work, under the electrochemical conditions, the oxidative and reductive behaviors of the PQD@SiOx were studied. Also, through in-situ spectroelectrochemical study, the electrochemically induced irreversible deformation process were tracked. The findings of this study could be used to understand role of silica coverage and develop the strategy to improve the protecting behavior of the silica for the PQD cores to utilize into the photoelectrochemical cells.

EDOT substitution site effect on fluorenone acceptor units: electrochemical polymerization and electrochromic properties of D-A systems

A series of donor-acceptor-donor type molecules (P(2,7-DEF) and P(3,6-DEF)) based on fluorenone acceptor units and 3,4-ethylenedioxythiophene (EDOT) donor units were successfully obtained by Stille coupling reaction in this work, and then generated their corresponding D-A polymers by electrodeposition method. As prepared P(2,7-DEF) and P(3,6-DEF) were characterized by CV, UV–vis spectroscopy, SEM, spectroelectrochemistry, and kinetic studies. Both of these two monomers revealed bright red/yellow light-emitting property in dilute solution. Since the π-conjugation length is longer, the oxidation potential of 2,7-DEF was reduced to 0.85 V, accompanied with red-shifted electronic spectra and emission spectra. The resulting P(2,7-DEF) demonstrated distinct electrochromic properties under various potentials with two different colors from dark-brown to blue-purple. Due to its more porous structure, P(2,7-DEF) also showed favorable optical contrast (26.3 %), very fast switching time (0.32 s), and decent coloration efficiency (221.25 cm2 C−1). However, P(3,6-DEF) displayed much worse electrochromic performances due to its bad electroactivity. P(2,7-DEF) also displayed better redox stability (remaining 79 % electroactivity after 1000 cycles), good optical stability (6 % reduction in optical contrast after 3200 s), and stable optical memory. From these results, P(2,7-DEF) can be further used as a promising near-infrared electrochromic materials.

2+1] Cycloadditions Modulate the Hydrophobicity of Ni‐N4 Single‐Atom Catalysts for Efficient CO2 Electroreduction

AbstractMicroenvironment regulation of M‐N4 single‐atom catalysts (SACs) is a promising way to tune their catalytic properties toward the electrochemical CO2 reduction reaction. However, strategies that can effectively introduce functional groups around the M‐N4 sites through strong covalent bonding and under mild reaction conditions are highly desired. Taking the hydrophilic Ni‐N4 SAC as a representative, we report herein a [2+1] cycloaddition reaction between Ni‐N4 and in situ generated difluorocarbene (F2C:), and enable the surface fluorocarbonation of Ni‐N4, resulting in the formation of a super‐hydrophobic Ni‐N4‐CF2 catalyst. Meanwhile, the mild reaction conditions allow Ni‐N4‐CF2 to inherit both the electronic and structural configuration of the Ni‐N4 sites from Ni‐N4. Enhanced electrochemical CO2‐to‐CO Faradaic efficiency above 98 % is achieved in a wide operating potential window from −0.7 V to −1.3 V over Ni‐N4‐CF2. In situ spectroelectrochemical studies reveal that a highly hydrophobic microenvironment formed by the −CF2− group repels asymmetric H‐bonded water at the electrified interface, inhibiting the hydrogen evolution reaction and promoting CO production. This work highlights the advantages of [2+1] cycloaddition reactions on the covalent modification of N‐doped carbon‐supported catalysts.

2+1] Cycloadditions Modulate the Hydrophobicity of Ni-N4 Single-Atom Catalysts for Efficient CO2 Electroreduction.

Microenvironment regulation of M-N4 single-atom catalysts (SACs) is a promising way to tune their catalytic properties toward the electrochemical CO2 reduction reaction. However, strategies that can effectively introduce functional groups around the M-N4 sites through strong covalent bonding and under mild reaction conditions are highly desired. Taking the hydrophilic Ni-N4 SAC as a representative, we report herein a [2+1] cycloaddition reaction between Ni-N4 and in situ generated difluorocarbene (F2C:), and enable the surface fluorocarbonation of Ni-N4, resulting in the formation of a super-hydrophobic Ni-N4-CF2 catalyst. Meanwhile, the mild reaction conditions allow Ni-N4-CF2 to inherit both the electronic and structural configuration of the Ni-N4 sites from Ni-N4. Enhanced electrochemical CO2-to-CO Faradaic efficiency above 98 % is achieved in a wide operating potential window from -0.7 V to -1.3 V over Ni-N4-CF2. In situ spectroelectrochemical studies reveal that a highly hydrophobic microenvironment formed by the -CF2- group repels asymmetric H-bonded water at the electrified interface, inhibiting the hydrogen evolution reaction and promoting CO production. This work highlights the advantages of [2+1] cycloaddition reactions on the covalent modification of N-doped carbon-supported catalysts.

In Situ Spectroelectrochemical Study of Acetate Formation by CO2 Reduction Using Bi Catalyst in Amine-Based Capture Solution.

Carbon capture and utilization (CCU) are technologies sought to reduce the level of CO2 in the atmosphere. Industrial carbon capture is associated with energetic penalty, thus there is an opportunity to research alternatives. In this work, spectroelectrochemistry was used to analyze the electrochemical CO2 reduction (eCO2R) in CO2 saturated monoethanolamine (MEA)-based capture solutions, in a novel CCU process. The in situ Fourier transform infrared (FTIR) spectroscopy experiments show that at the Bi catalyst, the active species involved in the eCO2R is the dissolved CO2 in solution, and not carbamate. In addition, the products of eCO2R were evaluated under flow, using commercial Bi2O3 NP as catalyst. Formate and acetate were detected, with normalized FE for acetate up to 14.5 %, a remarkable result, considering the catalyst used. Acetate is formed either in the presence of cetrimonium bromide (CTAB) as surfactant or at higher current density (>-100 mA cm-2) and the results enabled the proposition of a pathway for its production. This work sheds light on the complex reaction environment of a capture medium electrolyte and is thus relevant for an improved understanding of the conversion of CO2 into value-added products and to evaluate the feasibility of a combined CCU approach.

Synthesis, Characterization, and Properties of a Titanium(IV)-Tetrathiafulvalene-Based Complex.

To deeply investigate the interaction between a tetrathiafulvalene (TTF) unit and a Ti(IV) center, a monomeric heteroleptic octahedral Ti(IV) complex containing a diimine ligand composed of a 1,10-phenanthroline core fused with a TTF fragment (ligand 2a) was prepared. The stable complex formulated as Ti(1)2(2a), where 1 is a 2,2'-biphenolato derivative, was efficiently synthesized by following a one-step approach. This complex and its model species [Ti(1)2(2b)] were fully characterized in solution, and their solid-state structures were established by single-crystal X-ray diffraction analysis. Density functional theory calculations allowed the assignment of the frontier orbitals involved in the electronic transitions characterized by ultraviolet-visible absorption spectroscopy. Electrochemical and spectroelectrochemical studies revealed that the TTF unit within Ti(1)2(2a) can undergo two reversible one-electron oxidation processes; a reversible one-electron reduction of the Ti(IV) atom was highlighted. The photophysical measurements performed for this donor-acceptor molecular system indicated that an electron transfer process upon light excitation occurred within Ti(1)2(2a).

Mechanism Studies in Electrochemical Depolymerization Processes of Alkali and Organosolv Lignin

AbstractTo better understand the process and mechanism of lignin structural changes and relative product formation during PbO2 anode electrolysis, a Ti/Sb−SnO2/PbO2 composite electrode has been prepared and utilized for the alkaline electrolytic oxidation of both alkali lignin (AL) and bagasse organosolv lignin (OL). By combining electrochemical measurements, in‐situ FTIR, 2D‐HSQC NMR, and product distribution analysis, we not only investigate the impact of influence factors on the process of lignin depolymerization, but also reveal the depolymerization mechanism from the whole process of lignin structural changes in details. Under certain electrolysis conditions, the highest vanillin yield, 10.1 mg g−1, has been obtained through the electrolysis of alkali lignin, whereas the highest syringaldehyde yield of 4.0 mg g−1 has been achieved during the electrolysis of organic solvent lignin. In particular, AL mainly performs depolymerization through the selective cleavage C−C bonds to produce a series of G unit monomer products of vanillin, acetovanillone, and vanillic acid. By contrast, the depolymerization of OL shows significant selectivity in H units. Particularly, the production of the major H unit monomer product of 4‐vinylphenol has been confirmed by IR spectroelectrochemical studies from the oxidation and decarboxylation of p‐coumaric acid unit.

Dimerization of 9-Phenyl-ferroceno[2,3]indenylmethyl Radicals: Electrochemical and Spectroelectrochemical Studies.

We report on three new 9-phenyl-substituted ferroceno[2,3]indenylmethylium dyes 1 + -3 + with electron-donating (OMe, Me) or electron-withdrawing (CF3) substituents. Complexes 1 + -3 + exist as racemic mixtures of Rp and Sp enantiomers. Pyramidalization at the methyl C atom in the precursor carbinol species 1-OH-3-OH or the corresponding one-electron reduced radicals induces a second stereocenter, as the 9-phenyl substituent may reside in an endo or an exo position. Indeed, alcohol 2-OH crystallizes as a racemate of Rp,S and Sp,R isomers. Cationic complexes 1 + -3 + are of deep green color and show intense electronic absorption in the visible. The oxidation and reduction processes are thoroughly investigated by means of cyclic voltammetry and UV/vis/NIR spectroelectrochemistry, the latter showing their electrochromic behavior. T-dependent EPR spectroscopy, EPR spin counting at 20 °C, as well as the UV/vis/NIR spectra of the reduced samples suggest that the one-electron reduced, neutral radicals dimerize nearly quantitatively (≥99.98%). Chemical reduction of 2 + furnished an isomeric mixture of dimeric 2-2. As was shown by cyclic voltammetry and UV/vis/NIR spectroelectrochemistry, the latter dimer redissociates to monomers 2 + upon oxidation, thereby closing a reversible cycle of redox-induced C-C bond making and breaking.

Zirconium-based hydrophobic-MOFs as innovative electrode modifiers for flibanserin determination: Exploring the electrooxidation mechanism using a comprehensive spectroelectrochemical study.

Threedifferent types of Zr-based MOFs derived from benzene dicarboxylic acid (BDC) and naphthalene dicarboxylic acid as organic linkers (ZrBDC, 2,6-ZrNDC, and 1,4-ZrNDC) were synthesized. They were characterized using X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform IR spectroscopy (FT-IR), and Transmission electron microscopy (TEM). Their hydrophilic/hydrophobic nature was investigated via contact angle measurements; ZrBDC MOF was hydrophilic and the other two (ZrNDC) MOFs were hydrophobic. The three MOFs were combined with MWCNTs as electrode modifiers for the determinationof a hydrophobic analyte, flibanserin (FLB), as a proof-of-concept analyte. Under the optimized experimental conditions, a significant enhancement in the oxidation peak current of FLB was observed when utilizing 2,6-ZrNDC and 1,4-ZrNDC, being the highest when using 1,4-ZrNDC. Furthermore, a thorough investigation of the complex oxidation pathway of FLB was performed by carrying out simultaneous spectroelectrochemical measurements. Based on the obtained results, it was verified that the piperazine moiety of FLB is the primary site for electrochemical oxidation. The fabricated sensor based on 1,4-ZrNDC/MW/CPE showed an oxidation peak of FLB at 0.8V vs Ag/AgCl. Moreover, it showed excellent linearity for the determinationof FLB in the range 0.05 to 0.80μmol L-1 with a correlation coefficient (r) = 0.9973 and limit of detection of 3.0nmol L-1. The applicability of the developed approach was demonstrated by determinationof FLB in pharmaceutical tablets and human urine samples with acceptable repeatability (% RSD values were below 1.9% and 2.1%, respectively) and reasonable recovery values (ranged between 97 and 103% for pharmaceutical tablets and between 96 and 102% for human urine samples). The outcomes of the suggested methodology can be utilized for the determinationof other hydrophobic compounds of pharmaceutical or biological interest with the aim of achieving low detection limits of these compounds in various matrices.

Structure Activity Relationships for Second‐Coordination Sphere Functional Group Dependent CO2 Reduction by Manganese Bipyridyl Electrocatalysts

AbstractA series of twelve second coordination sphere (SCS) functionalized manganese tricarbonyl bipyridyl complexes are investigated for their electrocatalytic CO2 reduction properties in acetonitrile. A qualitative and quantitative assessment of the SCS functional groups is discussed with respect to the catalysts’ thermodynamic and kinetic efficiencies, and their product selectivities. In probing a broad scope of functional groups, it is clear that only the aprotic ortho‐arylester SCS is capable of promoting the highly desired low‐overpotential proton‐transfer electron‐transfer (PT‐ET) pathway for selective CO production. The ortho‐phenolic analogues cause an increase in overpotential with a product selectivity favoring H2 evolution, consistent with a high‐overpotential pathway via the anionic [Mn−H]− intermediate. Alternative aprotic Lewis base functional groups such as trifluoromethyl, morpholine and acetamide are shown to also be capable of intermediate manganese hydride generation. The tertiary amine substituent, 2‐morpholinophenyl, exhibits a desirable product distribution characteristic of syn‐gas (CO : H2=30 : 48) with an impressive turnover frequency, while the secondary amine group, 2‐acetamidophenyl, induces a notable shift in selectivity with a faradaic yield of 55 % for the formate (HCO2−) product. In addition to their catalytic properties, cyclic voltammetry and infrared spectroelectrochemistry (IR‐SEC) studies are presented to probe pre‐catalyst electronic properties and the two‐electron reduction activation pathway.

Electrochemical synthesis of donor-acceptor triazine based polymers with halochromic and electrochromic properties

Two triazine monomers substituted with aromatic α,β unsaturated ketones (chalcones) as connecting arms, holding triphenylamine or carbazole ending groups, were by the first time synthesized using commercial and inexpensive starting materials in just two steps. Triphenylamine and carbazole groups were strategically introduced in order to allow electrochemical polymerization and redox activity of the obtained films. The chalcone, together with the triphenylamine or carbazole outer groups, give rise to the formation of a donor-acceptor systems, allowing the generation of photoinduced intramolecular charge transfer (ICT) electronic transitions and providing basic sites for protonation. Because of the star-like chemical structure of the used triazine, electrochemical polymerization of these monomers conducted to the formation of hyperbranched structures. The polymeric materials exhibited not only electrochromic properties but also showed a halochromic behavior. Spectroelectrochemical studies of the films showed different colorations in the three redox states (neutral, semioxidized and fully oxidized). The color changes are fast and easily detected by the naked eye. Electrochemical parameters such as optical contrast, coloration efficiency, optical memory, and long-term stability for both films were obtained and compared. A quasi-solid window-type electrochromic device was assembled using the electrogenerated polymer with the best electrochromic performance and stability. Moreover, the triphenylamine based polymer showed reversible color changes upon acid-base vapor exposure cycles, demonstrating that this polymer can be used not only in electrochromic devices but also in acid vapor sensors.