Foram estudados os filmes finos eletrocrômicos de WO3, MoO3 e PEDOT:PSS e aplicados em pequenos dispositivos eletrocrômicos. Os filmes finos de WO3 foram produzidos por meio do processo de eletrodeposição galvanostática a partir de um sol de ácido peroxotungstênico. Realizaram-se dois estudos de eletrodeposição dos filmes de WO3: 1º) produziu-se filmes em diferentes correntes -0,45 -0,50, -0,60 e -1,0 mA com tempo de 600 segundos; 2º) produziu-se filmes variando os tempos de eletrodeposição de 100, 200, 300, 400, 500 e 600 s com corrente de -0,45 mA. O tratamento térmico foi efetuado a 120 ºC por 1 hora. Os filmes de WO3 eletrodepositados com corrente -0,45 mA no tempo de 600 s foram estudados com maiores detalhes. Os filmes com espessura de 140 nm apresentaram mudança na coloração de transparente para azul em resposta a aplicação de potencial de -1,0 a 1,0 V. A variação em transmitância foi medida no visível (λ = 633 nm) resultando em ΔT = 61 %. A densidade de carga foi de 35 mC/cm2 e a estabilidade eletroquímica foi de até 3.000 ciclos. As medidas de difração de raios-X mostraram que a estrutura dos filmes de WO3 é amorfa e as imagens de microscopia eletrônica de varredura (MEV) evidenciaram uma superfície homogênea e sem rachaduras. O filme de PEDOT:PSS depositado por dip-coating apresentou uma espessura em torno de 400 nm, mudança de coloração de azul para transparente com a aplicação do potencial de -1,0 a 1,0 V e ΔT= 50 % para o filme de uma camada. Os filmes de MoO3 foram depositados pela técnica de spin-coating e avaliados conforme o número de camadas (1 a 10 camadas) sendo os melhores resultados foram obtidos para a amostra composta por 9 camadas. Este filme apresentou densidade de carga em torno de 25 mC/cm2 e uma mudança de cor de transparente (T= 80%) para azul (T=38%) após a aplicação de potencial de 1,5 e -1,5 V, respectivamente. Foram confeccionados e estudados dispositivos eletrocrômicos (ECDs) com os filmes finos de WO3 e PEDOT:PSS, eletrólitos poliméricos a base de hidroxipropilcelulose (HPC) e goma gelana (GGLA) e contra eletrodo de CeO2-TiO2. As melhores respostas óticas foram obtidas com o dispositivo eletrocrômico WO3/HPC/CeO2-TiO2, sendo ΔT=29% e a densidade de carga de 12 mC/cm2. A melhor estabilidade em função do número de ciclos de coloração/descoloração de 5.500 foi obtido com o dispositivo eletrocrômico WO3|GGLA-PVP-NHS|CeO2-TiO2 com glicerol. / Electrochromic WO3, MoO3 and PEDOT: PSS thin films were deposited and characterized. WO3 thin films were produced using the galvanostatic electrodeposition process from peroxotungstic acid sol. There were two studies of electrodeposition of WO3 films: 1) films were produced in different streams -0.45 -0.50, -0.60 and -1.0 mA with a time of 600 seconds, and 2) produced films were electrodeposited varying times 100, 200, 300, 400, 500 and 600 s with a current of -0.45 mA. The heat treatment was performed at 120 °C for 1 hour. The WO3 films electrodeposited with -0.45 mA current for 600 s were chosen and studied deeply. These films with a thickness of 140 nm showed change in color from transparent to blue in response to applied potential of -1.0 to 1.0 V. The variation in transmittance was measured at λ = 633 nm, resulting in ΔT = 61%, charge density of about 35 mC/cm2 and electrochemical stability up to 3,000 cycles. X-ray diffractograms showed that the structure of the films is amorphous and scanning electron microscopy (SEM) images showed a homogeneous surface without cracks. The film of PEDOT: PSS deposited by dip-coating had a thickness around 400 nm, color change from blue to transparent upon applied potential of -1.0 to 1.0 V and ΔT = 50% for the one layer film. The MoO3 films were deposited by spin-coating and evaluated as the number of layers (1 to 10 layers) appointing the best results for the sample with 9 layers. This displayed the charge density of around 25 mC/cm2 and a color change from transparent (T = 80%) to blue (T = 38%) after applying the potential of 1.5 and -1.5 V, respectively. Furthermore, the electrochromic devices containing WO3 and/or PEDOT: PSS thin films, polymer electrolytes based cellulose and/or gellan gum and counter electrode of CeO2-TiO2 were assembled and characterized. The best responses of ΔT = 29% and charge density of 12 mC/cm2 were obtained for the electrochromic device with WO3/cellulose/CeO2-TiO2 configuration. However, the best coloring/bleaching stability of 5,500 cycles was obtained with the electrochromic device WO3|GGLA-PVP-NHS|CeO2-TiO2 with glycerol configuration.

O presente trabalho apresenta os resultados de preparação e caracterização de cinco dispositivos eletrocrômicos (DEC) compostos por filmes finos de óxidos de metais de transição, tais como WO3, WO3:Ta, Nb2O5:Mo e NiOx como camadas eletrocrômicas e CeO2-TiO2 como contra-eletrodo transparente. Os eletrólitos usados nestes dispositivos foram à base de amido plastificado com glicerol e contendo LiClO4 ou KOH dependendo da camada eletrocrômica. Todos os filmes finos foram preparados pelo processo sol-gel e depositados sobre FTO pela técnica de dip-coating. Os dispositivos foram caracterizados através da técnica de voltametria cíclica, espectroscopia na região do UV-visível-NIR (300–1100 nm) e densidade de carga inserida/extraída ao longo dos ciclos cronoamperométricos. A partir dos valores obtidos para a densidade de carga inserida e a transmitância em 550 nm e em 633 nm e com o uso de uma equação apropriada obtiveram-se os valores de eficiência eletrocrômica dos dispositivos eletrocrômicos. Foram feitas também medidas de densidade ótica em função do potencial e transmitância em função do tempo. Os resultados de densidade de carga para os dispositivos eletrocrômicos com WO3, WO3:Ta e Nb2O5:Mo mostraram que os processos de inserção/extração dos íons lítio são reversíveis, sendo que a extração é muito rápida da ordem de 10s. Através dos espectros de transmissão observou-se uma boa variação na transmitância entre os estados coloridos e descoloridos (T), sendo que o DEC com WO3 e eletrólito com concentração de LiClO4, [O]/[Li]=10 obteve a maior variação de T = 38,4% em 633 nm. Isso resultou num alto valor de eficiência eletrocrômica de 77,5 cm2/C. O DEC com NiOx apresentou uma menor variação na transmitância, 23,8% em 550 nm para o ciclo 3000, resultando num menor valor de eficiência eletrocrômica, 24,9 cm2/C. O presente trabalho apresenta também os resultados da preparação e caracterização de eletrólitos sólidos poliméricos contendo amido, glicerol e hidróxido de potássio, os quais foram caracterizados através da técnica de espectroscopia de impedância eletroquímica e a partir destes resultados os valores das suas condutividades iônicas foram calculadas. Fez-se também medidas de transmissão ótica na região do UV-visível-NIR (300-1100 nm). O melhor valor de condutividade iônica foi obtido para o filme com 25% de glicerina e 35% de KOH em relação à massa do amido, sendo 4,92∙10-5 S∙cm-1 a 30oC. Os resultados obtidos neste trabalho mostram que os eletrólitos sólidos poliméricos à base de amido podem ser muito interessantes para aplicação em dispositivos eletrocrômicos como, por exemplo, janelas eletrocrômicas em arquitetura. / This dissertation presents the results of preparation and characterization of five electrochromic devices (DEC) composed of thin films of transition metal oxides, such as WO3, WO3:Ta, Nb2O5:Mo and NiOx as electrochromic layers and CeO2-TiO2 as a transparent counter-electrode. The electrolytes used in these devices were starch-based plasticized with glycerol containing LiClO4 or KOH, depending on the electrochromic layer. All the thin films were prepared by sol-gel process and deposited onto FTO by dip-coating technique. The devices were characterized by means of cyclic voltametry, spectroscopy in the region of UV-visible-NIR (300-1100 nm) and the inserted/extracted charge density along the chronoamperometric cycles. From the values obtained for the inserted charge density and the transmittance in 550 nm and 633 nm and using an appropriate equation the values of electrochromic efficiency of the electrochromic devices were obtained. Measurements of optical density in function of the potential and transmittance in function of the time were also taken. The results of charge density for the electrochromic devices with WO3, WO3:Ta and Nb2O5:Mo showed that the processes of insertion/extraction of the lithium ions are reversible and the extraction is very fast, i.e., of the order of 10s. Through the transmission spectra it was possible to observe a good variation in the transmittance between the coloured and bleached states (T), given that the DEC with WO3 and electrolyte with concentration of LiClO4, [O]/[Li]=10 obtained the largest variation of T = 38.4% in 633 nm. This resulted in a high value (77.5 cm2/C) of electrochromic efficiency. The DEC with NiOx presented a smaller variation in the transmittance, i.e., 23.8% in 550 nm for cycle 3000, resulting in a lower value of electrochromic efficiency, 24.9 cm2/C. This work also presents the results of the preparation and characterization of solid polymeric electrolytes containing starch, glycerol and potassium hydroxide characterized by the technique of electrochemical impedance spectroscopy. From these results the values of their ionic conductivities were calculated. Measurements of optical transmission in the region of UV-visible-NIR (300-1100 nm) were also taken. The best value of ionic conductivity, i.e., 4.9210-5 Scm-1 at 30oC was obtained for the film with 25% of glycerol and 35% of KOH in relation to the mass of starch. The results presented in this work show that starch-based solid polymeric electrolytes can be very interesting for application in electrochromic devices as, for example, smart windows in architecture.

Este trabalho apresenta resultados da preparação e caracterização de filmes finos de pentóxido de nióbio (Nb2O5) dopados com isopropóxido de zircônio (IV) Zr[O(CH2)2CH3]4, obtidos via processo sol-gel. A adição do precursor dopante teve como finalidade estudar a sua influência sobre as propriedades eletroquímicas destes filmes. Os sóis destinados à deposição destes filmes foram preparados a partir da mistura de pentacloreto de nióbio (NbCl5 anidro), n-butanol e ácido acético e sua submissão à ação de irradiação ultrasônica. A obtenção das camadas delgadas de Nb2O5:Zr, com diferentes espessuras (1 a 6 camadas), sobre um substrato de vidro recoberto com camada condutora eletrônica (ITO), fez-se pelo processo sol-gel juntamente com a técnica de imersão vertical (dip-coating). Os filmes foram submetidos a um tratamento térmico entre 450ºC e 560ºC, em atmosfera de ar, por 5 e 10 minutos. O estudo efetuado revelou que estes filmes finos de Nb2O5:Zr, apresentaram influência de concentração de zircônio, número de camadas e tempo de tratamento térmico nas propriedades eletroquímicas. As medidas de voltametria cíclica demonstraram que o processo de inserção/extração é reversível, enquanto medidas cronoamperométricas, demonstraram que o processo de intercalação atinge o seu valor máximo (35 mC/cm2) em 30s à -1,8V, para filmes dopados numa razão molar de 0,5% e com 5 camadas e tratamento térmico de 450°C por 10 minutos. Estes filmes também apresentaram nas análises microscópicas por MEV uma morfologia muito uniforme, lisa e sem rachaduras. Além disso, foi comprovada por análises EDX a presença de zircônio nos filmes. Todos estes resultados mostraram que os filmes de Nb2O5:Zr são promissores e excelentes candidatos à substituir filmes de WO3.em aplicações eletroquímicas. / This work consists of the preparation and characterization of niobium (V) oxide films (Nb2O5) doped with zirconium (IV) isopropoxide Zr[O(CH2)2CH3]4, was obtained by sol-gel process. The main objective of dopant addition was to study its influence on eletrochemical properties of these films. The sols used to deposition of these films were prepared from the mixture of niobium (V) (NbCl5), butanol and acetic acid by ultrasonic radiation action. The obtaining of the thin layers of Nb2O5:Zr with different thick (from 1 to 6 layers), on a glass substrate recovered with conductor layer ( ITO) was carried out by sol - gel process and dip-coating technique. The films were subjected to a thermal treatment between 450ºC and 560ºC, during some minutes in air atmosphere for 5 and 10 minutes. The study performed showed that these thin films of Nb2O5:Zr, presented influence of zirconium concentration, numbers of layers and time of termic treatment in the electrochemical properties. The measures of cyclic voltammetry showed that the process of insertion and extraction is reversible whereas the chronoamperometry measures showed the intercalation process has as maximum values (35mC/cm2) in 30s at -1,8V to doped films in a molar ration of 0,5% and with 5 layers and termci treatment of 450oC for 10 minutes. These films also presented in microscopic analysis by SEM a morphology very consistent, smooth and without cracks. Besides, it was proved by analysis by EDX the zirconium presences in the fims. All these results showed that the films of Nb2O5:Zr are promising and excellent application to replace films of WO3 in electrochemical application.

<p>There are still technique hurdles that needed to be overcome in the commercialization of electrochromic devices (ECDs) for energy-saving smart windows. Among them, the long-term stability of ECDs and the high fabrication cost are <a>the critical issues</a>. The pricey ECDs can only be paid off through saving the energy for years, and their price will be dramatically lower if they can be solution-processed. Here, we studied the ions behaviors in the open-circuit state of electrochromic conjugated polymers (ECPs) which is important to the stability of ECDs during the operation. Moreover, we investigated the solution-processable ion storage layers and paired them with p-type ECPs and demonstrated the possibility of using them in the highly efficient roll-to-roll fabrication of ECD.</p> <p>The crosslinkable non-color changing nitroxy radical-based polymer was investigated as the ion storage layer. With the applied of crosslinking strategy, the dissolution problems of radical polymers-based counter electrode in the electrolyte was suppressed, resulting in the enhancement of both performance and cycling stability of ECDs. Although p-type ion storage materials are widely studied as the ion storage layers for ECPs, they need to go through complicated pretreatment processes, including pre-oxidation, washing, and drying, before they can be paired with ECPs in an ECD. This complicated process greatly increases the fabrication cost. </p> <p>In our last work, we applied the UV ozone (UVO) pretreatment to the solution-processed n-type niobium oxide and evaluated its potentials to be used as the ion storage layer for p-type ECPs. The UVO pretreatment generates strong oxidants like ozone or atomic oxygen which induce the photolysis of organic residues of ligands and organic solvent trapped in the solution-processed metal oxide layer led to the formation of free radical species. These highly reactive species promoted the formation of the amorphous metal−oxygen network. Following by low-temperature annealing (< 150 ^oC), the ion-storage properties of niobium oxide is comparable with the high temperature annealed (300 ^oC) niobium oxide. The method is successfully applied to fabricate niobium oxide on a flexible conductive substrate and demonstrate the capability to pair with p-type ECPs and fabricate high-performance ECDs without the need of any pretreatments. The low-temperature solution processing of both layers will significantly reduce the fabrication cost of ECDs. </p>

In this study, WO3 and NiO thin films were deposited on the ITO/Glass substrates by radio frequency (RF) magnetron sputtering, respectively. The physical and electrochromic properties of thin films were investigated. On the other hand, the lithium perchlorate (LiClO4) powder was dispersed in propylene carbonate (PC) solvent to complete 1 M electrolyte. Then, as the 4.5 wt.% of ethyl cellulose and 8 wt.% ethylene carbonate (EC) were added to this electrolyte under stirring, a gel polymer electrolyte (GPE) was formed. Finally, the WO3 and NiO thin films obtained with the optimal deposition parameters were combined with the GPE to set up a complementary electrochromic device (CECD). The effects of the various coloring voltages on the electrochromic properties of CECD are investigated. The memory effect, energy-saving efficient, response time and switch lifetime of CECD are also estimated and discussed. Experimental results reveal that the amorphous thin films can be obtained with the RF power of 100 W and oxygen concentration of 60% at room temperature (RT). The thicknesses of WO3 and NiO films were approximately 530 nm and 180 nm, respectively. The stoichiometric of thin films were 2.99 for O/W ratio and 1.01 for O/Ni ratio. The GPE [(1 M LiClO4+PC)+ethyl cellulose(4.5 wt.%)+EC(8 wt.%)] exhibits a viscosity coefficient of 100 mPa∙s, a maximum ion conductivity (£m) of 7.17 mS/cm, a minimum activation energy (Ea) of 0.033 eV and a average visible transmittance of 82% at RT. The optimal electrochromic CECD (Glass/ITO/WO3/GPE/NiO/ITO/Glass) biased with a coloring/bleaching voltage of ¡Ó2.2 V revealed a transmittance variation (£GT%) of 54.53%, an optical density change (£GOD) of 0.790, an intercalation charge (Q) of 6.28 mC/cm2 and a coloration efficiency (£b) of 125.21 cm2/C at a wavelength (£f) of 550 nm. The chromaticity coordinates of CECD were x=0.289 and y=0.365 under the colored state. In addition, the energy-saving efficient of CECD was 15.19 W/V-m2 over the wavelength range between 380 nm and 780 nm. Also, it presented an open-circuit memory effect that the colored transmittance (£f at 550 nm) was 18.9% in 24 h. The total response time of the CECD was about 4 s for coloring and bleaching steps. After the repeated switch of 1,000 times, the £GT% of CECD was 43.57%. In this study, WO3 and NiO thin films with good adhesion, amorphous, and nearly stoichiometric were successfully deposited by RF sputter. Furthermore, high £m and high transmittance of GPE can be prepared easily and inexpensively. Our results demonstrated that the CECD exhibited the advantages of low applied voltage, high £b, fast response time and long-term memory characteristics.

Different substituted thiophene and pyrrole monomers namely hexamethylene (bis-3-thiopheneacetamide) (HMTA), N-(4-(3-thienylmethylene)-oxycarbonylphenyl)maleimide (MBThi), 2,4,6-Tris-(4-pyrrol-1-yl-phenoxy)-[1,3,5]triazine (TriaPy), 2,4,6-Tris-(thiophen-3-ylmethoxy)-[1,3,5] triazine (TriaTh), and N-(2-(thiophen-3-yl)methylcarbonyloxyethyl) maleimide (NMT) were synthesized. The chemical structures of the monomers were characterized by Nuclear Magnetic Resonance (1H-NMR and 13C-NMR) and Fourier Transform Infrared (FTIR) Spectroscopies. Electrochemical behavior of the monomers in the presence and absence of comonomers were studied by cyclic voltammetry. Subsequently, monomers were homopolymerized and copolymerized via electrochemical methods and the resultant polymers were characterized by FTIR, Scanning Electron Microscopy (SEM) and conductivity measurements. Second part of the study was devoted to investigate one of most interesting property of conducting polymers, the ability to switch reversibly between the two states of different optical properties, &ldquo / electrochromism&rdquo / . In recent years there has been a growing interest in application of conducting polymers in electrochromic devices. Thus, electrochromic properties of the synthesized conducting polymers were investigated by several methods like spectroelectrochemistry, kinetic and colorimetry studies. Spectroelectrochemistry experiments were performed in order to investigate key properties of conjugated polymers such as band gap, maximum absorption wavelength, the intergap states that appear upon doping and evolution of polaron and bipolaron bands. Switching time and optical contrast of the homopolymers and copolymers were evaluated via kinetic studies. Results implied the possible use of these materials in electrochromic devices due to their good electrochromic properties.

A monomer, 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl) benzenamine (SNS-NH2), was synthesized via the reaction of 1,4-di(2-thienyl)-1,4-butanedione with benzene-1,4-diamine. Chemical polymerization of the monomer yielded a polymer which was completely soluble in organic solvents. The chemical structures of both the monomer and the polymer were characterized by Nuclear Magnetic Resonance Spectroscopy (1H-NMR and 13C-NMR) and Fourier Transform Infrared (FTIR) Spectroscopy. The average molecular weight of the chemically synthesized polymer was determined by Gel Permeation Chromatography (GPC) as Mn = 2.2x103 g/mol. The electrochemical oxidative polymerization of SNS-NH2 was carried out via potentiodynamic electrolysis in the presence of LiClO4, NaClO4 (1:1) supporting electrolyte in acetonitrile. Electrochemical copolymerization of SNS-NH2 in the presence of 3,4-ethylenedioxythiophene (EDOT) was achieved in acetonitrile (ACN) / NaClO4/LiClO4 (0.1M) solvent-electrolyte couple via potentiodynamic electrolysis. Conductivities of samples were measured by four probe technique. Cyclic Voltammetry (CV) and Ultraviolet&ndash / Visible Spectroscopy were used to investigate electrochemical behavior of the monomer and redox reactions of conducting polymers. Surface morphologies of the polymer films were investigated by Scanning Electron Microscope (SEM). Second part of the study was devoted to investigate the one of most interesting property of conducting polymers, the ability to switch reversibly between the two states of different optical properties, &lsquo / electrochromism&rsquo / . The electrochromic properties of the conducting polymers were investigated via spectroelectrochemistry, kinetic and colorimetry studies. Spectroelectrochemistry analysis of homopolymer, P(SNS-NH2), reflected electronic transitions at 376 and 650 nm indicating &amp / #960 / -&amp / #960 / * transition and polaron band formation respectively. The polymer has an electronic bandgap of 2.12 eV with a yellow color in the fully reduced form and a blue color in the fully oxidized form. Switching ability of the homopolymer was evaluated by kinetic studies upon measuring the % transmittance as 20.7 % at the maximum contrast point. The spectroelectrochemical behavior of the P(SNS-NH2-co-EDOT) compare to that of the homopolymer revealed solid evidence of copolymerization based upon the differences in the spectral signatures. Copolymer revealed multichromic property with five different colors at different applied potentials. Colorimetry studies for P(SNS-NH2-co-EDOT) proved that it is possible to provide fine tuning of these colors by varying applied potential during synthesis. The results of colorimetry, spectroelectrochemistry and FTIR studies showed the possible control of the color of the electrochromic material in a predictable, controlled and reproducible manner. As the last part of the study, dual-type complementary colored electrochromic devices (ECD) using P(SNS-NH2) and P(SNS-NH2-co-EDOT)/poly(3,4-ethylenedioxythiophene) (PEDOT) in sandwich configuration were constructed and evaluated. Spectroelectrochemistry, electrochromic switching and open circuit stability of the devices were investigated by UV-Vis Spectrophotometer and Cyclic Voltammetry. They have shown to possess good switching times, reasonable contrasts and high stabilities.

A new polythiophene derivative, poly-2,3-bis(4-tert-butylphenyl)-5,8-bis(4-hexylthiophen-2-yl)quinoxaline PHTQ was synthesized by both chemical and electrochemical polymerization and its electrochemical properties were reported. The monomer was electrochemically polymerized in the presence of tetrabutylammonium hexafluorophosphate(TBAPF6) as the supporting electrolyte in dichloromethane-acetonitrile (5:95, v:v). Nuclear magnetic resonance spectroscopy (1H-NMR, 13C-NMR) was utilized for the characterization of the monomer and the soluble polymer. The polymer was further characterized by Gel Permeation Chromatography (GPC). Spectroelectrochemistry and switching ability of the polymer were investigated by UV&ndash / vis spectrophotometer and cyclic voltammetry. The polymer revealed three distinctive colors upon doping which indicated that the polymer is multichromic. Tert-butyl group on the pendant phenyl rings and hexyl groups on thiophene enhanced the solution processability of the electrochromic polymer. The electrochemical and spectral properties of the chemically synthesized polymer were investigated via spray coating on ITO glass slides. Electrochemical copolymerization of 2,3-bis(4-tert-butylphenyl)-5,8-bis(4-hexylthiophen-2-yl) quinoxaline (HTQ) with 3,4-ethylenedioxythiophene(EDOT) was performed to fulfill a strategy in achieving fine-tuned electrochromic properties. The copolymer, P(HTQ-co-EDOT) was characterized via detailed studies of cyclic voltammetry and spectroelectrochemistry. Band gap (Eg) of the copolymer was calculated as 1.4 eV and showed 34 % optical contrast with switching times less than 1 second.

Synthesis of 2-[(3-thienylcarbonyl)oxy]ethyl 3-thiophene carboxylate (TOET), 2,3-bis-[(3-thienylcarbonyl)oxy]propyl 3-thiophene carboxylate (TOPT), and 3-[(3-thienylcarbonyl)oxy]-2,2-bis{[(3-thienylcarbonyl)oxy]}propyl 3- thiophene carboxylate (TOTPT), and their copolymerization either with thiophene or pyrrole were achieved. The chemical structures of the monomers were investigated by Nuclear Magnetic Resonance Spectroscopy (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Electrochemical behavior of the monomers and copolymers were studied by cyclic voltammetry (CV). The resultant conducting copolymers were characterized via FTIR, Thermal Gravimetry Analysis (TGA), Differential Scanning Calorimetry (DSC), and morphologies of the films were inspected by Scanning Electron Microscope (SEM). Conductivities of the samples were measured by using four-probe technique. The electrochromic and spectroelectrochemical properties of the copolymers were investigated.

Terephthalic acid bis-(thiophen-3-ylmethyl)thioester (TTMT) was synthesized via the reaction of thiophen-3-ylmethanethiol with terephthaloyl dichloride. Nuclear magnetic resonance (1H-NMR) and Fourier transform infrared (FTIR) spectroscopies were utilized for the characterization of the monomer. This 3-functionalized thiophene monomer was polymerized in the presence of thiophene (Th) and pyrrole (Py) upon constant potential application in acetonitrile/tetrabutylammonium tetrafluoroborate (TBAFB). The resulting copolymers were characterized via cyclic voltammetry (CV), FTIR, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), four-probe technique conductivity measurement and UV-Vis spectroscopy. Spectroelectrochemical analysis of P(TTMT-co-Th) revealed &amp / #960 / to &amp / #960 / * transition at 476 nm with a band gap of 2.0 eV whereas, &amp / #955 / max and Eg were found as 375 nm and 2.4 eV for P(TTMT-co-Py), respectively. Dual type electrochromic devices (ECDs) of P(TTMT-co-Th) and P(TTMT-co-Py) with poly(3,4-ethylenedioxythiophene) (PEDOT) were constructed. Spectroelectrochemistry, switching ability, open circuit memory and stability of the devices were examined by UV-Vis spectroscopy and cyclic voltammetry. The device P(TTMT-co-Th)/PEDOT switches between brown and blue upon application of 0.0 V and +2.6 V, respectively with 11% optical contrast and 1.1 s as the switching time. On the other hand, P(TTMT-co-Py)/PEDOT ECD exhibits greenish yellow, grayish red and blue colors with the application of -2.4 V, 0.0 V and +0.8 V, respectively and the contrast between extreme potentials was 17.5% with a switching time of 1.6 s. 1-(4-Fluorophenyl)-2,5-di(thiophen-2-yl)-1H-pyrrole (FPTP) was synthesized and polymerized both chemically and electrochemically. Several analytical techniques, such as NMR, FTIR, CV, gel permeation chromatography (GPC), four-probe conductivity measurement, SEM were utilized when applicable. Spectroelectrochemistry experiments reflected a &amp / #960 / to &amp / #960 / * transition at 398 nm with a band gap energy of 1.94 eV for the polymer. A dual type electrochromic device (ECD) of PFPTP and poly(3,4-ethylenedioxythiophene) (PEDOT) was constructed. The device switches between yellowish brown and blue upon application of &amp / #8211 / 0.8 V and +1.1 V, respectively. Optical contrast was calculated as 19.4% with a switching time of 1.4 s at maximum contrast point.