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We fabricated a homogeneous thin film by blending a hole-transporting organic molecule having long alkyl chains, N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)-9,9-dioctylfluorene (DOFL-TPD), with InP/Z...

Charge transfer (CT) states at the donor–acceptor interfaces play an important role in organic optoelectronic devices, yielding photocarrier generation or recombination losses. In this study, we fabricate and characterize vacuum-deposited organic photodiodes (OPDs) composed of SubPc:C60 with various active-layer thicknesses and mixing ratios in terms of the charge separation efficiency (CSE) and charge collection efficiency (CCE). We demonstrate that the combined field-assisted quenching study using both photoluminescence (PL) and electroluminescence (EL) reveals detailed information on the device physics of bulk heterojunction photodiodes as related to the CT state. Our modified PL quenching efficiency approach allows us to reasonably evaluate the CSE. In addition, we find that the EL energy is closely related to the recombination loss factor, and the energy gap between PL and EL exhibits a strong linear relationship with the CCE. As a result, the energy gap is proved to be a meaningful indicator of the ...

tuning in the whole visible regime through large changes in the particle-particle separation originating from the electrophoretic movement of the charged particles while maintaining the ordered crystal structure under the external fields.[10] In spite of these merits, there is no report that considered these systems applicable for reversible switching for practical application. Although de-ionized water is the most suitable dispersion medium for producing high quality periodic crystalline structures with enhanced reflectance in these systems, the electrolysis of water molecules at the indium tin oxide (ITO) surface produces significant amounts of H+ and OH− ions as by-products at the cathode and anode, respectively. Therefore, the diffusion of those ions into colloidal arrays substantially limits the tuning stability and range because this phenomena induces decreased thickness of electrical double layer on the surface of the colloidal nanoparticles. To solve this problem, ITO surface was modified by various dielectric insulator passivation layers, including SiO2, SiN, polyimide, and parylene that can block electrochemical reactions at the electrodes (unpublished results). However, this methodology resulted in a substantial reduction of the color tuning range due to decreases in voltage applied to the colloidal dispersion because of the large amount of additional impedance introduced by the passivation layer. Considering the volume resistivity of these commonly used passivation materials (∼1016 Ω m), required thickness of the passivation layer should be at the sub-nm scale in order not to decrease the voltage applied significantly in colloidal dispersion. Preparation of such a thin and uniform film without any defected area is extremely difficult to achieve. Here we report our effort for achieving enhanced tuning stability of the colloidal photonic crystal composed of long-range ordered crystalline colloidal arrays through modifying the ITO electrode with ion exchange resins. The thin layer of over-coating on the ITO surface allowed increased number of cycles of stable color-tuning switching from red to green over 800 times, which is the best result ever reported for a tunable photo nic crystal whose Δλ can be manipulated more than 100 nm. Figure 1(a) depicts the device structure of a unit pixel and the concept of improving the stability of photonic structural color tuning through blocking ion diffusion from both electrodes by coating the electrode surface with a layer of ion-exchange resin. A colloidal dispersion composed of monodisperse 138 nm-diameter polystyrene (PS) nanoparticles dispersed in deionized water was injected between two electrodes. The strong negative charge of the nanoparticles and their thick electrical double layer induce the self-assembly of the long-range ordered colloids through electrostatic repulsion, which dominates the Structural Color Manipulation Using Tunable Photonic Crystals with Enhanced Switching Reliability

An electrically tunable photonic crystal is developed utilizing crystalline colloidal arrays of high refractive index particles. Through modulation of the refractive index of the particle, and the applied electric field, both the bandwidth and position of the photonic bandgap could be tuned. Full color modulation with high optical quality is achieved, which paves a way to develop a novel reflective display.

There are growing opportunities and demands for image sensors that produce higher-resolution images, even in low-light conditions. Increasing the light input areas through 3D architecture within the same pixel size can be an effective solution to address this issue. Organic photodiodes (OPDs) that possess wavelength selectivity can allow for advancements in this regard. Here, we report on novel push–pull D−π–A dyes specially designed for Gaussian-shaped, narrow-band absorption and the high photoelectric conversion. These p-type organic dyes work both as a color filter and as a source of photocurrents with linear and fast light responses, high sensitivity, and excellent stability, when combined with C60 to form bulk heterojunctions (BHJs). The effectiveness of the OPD composed of the active color filter was demonstrated by obtaining a full-color image using a camera that contained an organic/Si hybrid complementary metal-oxide-semiconductor (CMOS) color image sensor.

Thin-film color reflectors inspired by Morpho butterflies are fabricated. Using a combination of directional deposition, silica microspheres with a wide size distribution, and a PDMS (polydimethylsiloxane) encasing, a large, flexible reflector is created that actually provides better angle-independent color characteristics than Morpho butterflies and which can even be bent and folded freely without losing its Morpho-mimetic photonic properties.

Copolymers of poly(ethyl cyanoacrylate- co -methyl methacrylate) (PECA- co -PMMA) with various compositions were synthesized by free radical bulk polymerization in an effort to control degradation and stability as well as glass transition temperature to overcome intrinsic poor processability of the poly(ethyl cyanoacrylate) (PECA) homopolymer. The copolymers were found to have an alternating random tendency, which was responsible for the efficient inhibition of the unzipping degradation from the polymer chain. Consequently, the stability of the copolymers at elevated temperature and in solution was significantly improved compared to the PECA homopolymer. The glass transition temperatures of the copolymers were lowered by the incorporation of the methyl methacrylate (MMA), thereby further widening the operating temperature range of the polymer. On the other hand, the copolymer films exhibited hydrolytic degradation in phosphate buffered saline (PBS) solution at 37 °C, which is promising for their use as novel biomaterials.

Poly(ethyl cyanoacrylate) was synthesized using N , N ′-dimethyl- p -toluidine as an initiator through an anionic/zwitterionic pathway. The degradability and the degradation mechanism of the prepared polymer were examined from various viewpoints. A combination of TGA and GPC analysis allowed us to confirm that the thermal degradation of this polymer was predominantly due to an unzipping depolymerization process initiated from the polymer chain terminus. The polymer was inherently unstable and exhibited interesting degradation behavior in solution with basic reagents. The degradation in solution was also found to be attributed to the unzipping of the monomer from the chain end. However, the degradation behavior of the polymer could be controlled by changing solvents, temperatures, and additives. These findings give an insight into the degradation behavior of poly(alkyl cyanoacrylate)s, which is a crucial point in utilizing these polymer homologues for various applications.

Polyaniline coated poly(butyl methacrylate) core–shell particles were synthesized and formulated into electrically conductive colloidal inks appropriate for use in roll-to-roll printing. Since the first demonstration of an organic field-effect transistor, a specific interest in fabricating low-cost, large area organic electronics through the exploitation of conventional ink-jet, screen, or roll-to-roll printing technologies has developed. Using a commercial roll-to-roll printing press, interdigitated test figures were printed with the core–shell colloidal ink down to a line thickness of ca. 40 µm. The printed zones exhibited a conductivity of ca. 0.5 Ω−1 cm−1, though this conductivity could be modified by altering the composition of the ink to include more uncoated poly(butyl methacrylate) particles. Heating the printed zone above 35 °C allowed the core to flow, resulting in enhanced mechanical properties of the printed zone.

Complementary metal–oxide–semiconductor (CMOS) colour image sensors are representative examples of light-detection devices. To achieve extremely high resolutions, the pixel sizes of the CMOS image sensors must be reduced to less than a micron, which in turn significantly limits the number of photons that can be captured by each pixel using silicon (Si)-based technology (i.e., this reduction in pixel size results in a loss of sensitivity). Here, we demonstrate a novel and efficient method of increasing the sensitivity and resolution of the CMOS image sensors by superposing an organic photodiode (OPD) onto a CMOS circuit with Si photodiodes, which consequently doubles the light-input surface area of each pixel. To realise this concept, we developed organic semiconductor materials with absorption properties selective to green light and successfully fabricated highly efficient green-light-sensitive OPDs without colour filters. We found that such a top light-receiving OPD, which is selective to specific green wavelengths, demonstrates great potential when combined with a newly designed Si-based CMOS circuit containing only blue and red colour filters. To demonstrate the effectiveness of this state-of-the-art hybrid colour image sensor, we acquired a real full-colour image using a camera that contained the organic-on-Si hybrid CMOS colour image sensor.

Poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles with enhanced conductivity and processability were prepared by oxidative polymerization in dodecylbenzne sulfonic acid (DBSA) micellar solutions. DBSA was used to act simultaneously as a surfactant to form micelles and as a doping agent. Monomers of EDOT, which has extremely low solubility to water, were easily solubilized in aqueous DBSA micellar solution. The effects of DBSA on the resulting PEDOT structure, morphology and electrical property were investigated when DBSA was used in combination with two different oxidants, i.e., iron(III) chloride and ammonium persulfate. The electrical conductivity was varied with the polymerization conditions, and it was relatively high up to 50 S/cm. The morphology of the particles, determined by Field emission scanning electron microscopy (FE-SEM), appeared to be quite spherical and their sizes ranged from 35 to 100 nm in diameter. The colloidal properties of the PEDOT nanoparticles were also investigated.

The effect of methanol cosolvent on the synthesis of polypyrrole-silica colloidal nanocomposites using ultrafine silica sols in combination with both FeCl3 and APS oxidants has been investigated. Two protocols were evaluated: the addition of methanol to an aqueous silica sol and the addition of water to a methanolic silica sol. The latter protocol proved to be more robust, since it allowed colloidally stable dispersions to be prepared at higher methanol content (up to 50 vol% using the APS oxidant). This allowed greater control over the particle size of the nanocomposite particles. In general, the spectroscopic data, the particle size range, silica contents and electrical conductivities of these nanocomposites were similar to those reported earlier for purely aqueous formulations. Polypyrrole contents ranged from 49 to 71% by mass and particle diameters varied from around 160 to 360 nm. In terms of colloid stability, the APS oxidant was preferred for nanocomposite syntheses in the presence of methanol. However, the FeCl3 oxidant generally gave higher conductivities and narrower size distributions under comparable conditions. HF etching experiments combined with transmission electron microscopy studies indicated that, to a first approximation, these nanocomposite particles had core-shell morphologies, with a hydrophobic polypyrrole core and a hydrophilic silica shell that compose approximately one monolayer of silica sol particles. Finally, aqueous electrophoresis measurements suggested that the polypyrrole-silica nanocomposites were silica-rich and that the methanolic silica sol was more hydrophobic (lower surface charge density) than the aqueous silica sol.

The synthesis of colloidally stable nanocomposites comprising poly(3,4-ethylenedioxythiophene) (PEDOT) and a 20 nm diameter silica sol is described for the first time. Raspberry-shaped PEDOT−silica nanocomposites of submicrometer dimensions were obtained, with silica contents ranging from 19% to 80% by mass and with electrical conductivities as high as 0.2 S cm-1.

Carbon black-filled high-density polyethylene (HDPE)/ethylene ethylacrylate copolymer (EEA) blends were prepared and the effect of crosslinking of the blends on the positive temperature coefficient (PTC) stability was investigated. By irradiation and silane-crosslinking methods, crosslinked composites with various degrees of crosslinking were obtained. Crosslinking of the matrix polymer led to the disappearance of the negative temperature coefficient (NTC) phenomenon. Also, the PTC intensity increased with an increasing degree of crosslinking. The PTC stability of silane-crosslinked samples was notably improved at heat cycles of 140°C. This was sufficiently improved by both the silane- and radiation-crosslinking methods when they were treated at 85°C. Therefore, the limiting temperature of self-regulating heat is about 85°C. Both radiation- and silane-crosslinked samples are thought to be of use to the industry.

Chemical oxidative polymerization of aniline was performed in a micellar solution of dodecylbenzene sulfonic acid (DBSA, anionic surfactant) to obtain conductive nanoparticles with enhanced thermal stability and processability. DBSA was used to play both the roles of surfactant and dopant. The polymerization kinetics and optimum polymerization conditions were determined by UV–VIS spectra. The optimum molar ratio of oxidant to aniline was 0.5 and DBSA content was the most important factor in the formation of polyaniline (PANI) salt. The polymerization rate was increased with increasing DBSA concentration. The reaction model was proposed on the basis of the roles of DBSA. The electrical conductivity varied with the molar ratio of DBSA to aniline and the highest conductivity of particles was 24 S/cm. The layered structure due to PANI backbone separated by long alkyl chains of DBSA was observed and it seems to facilitate the electrical conduction. The doping level of particle was fairly high and was dependent on the preparative conditions. The average size of the PANI particles determined by Guinier plot of small-angle X-ray scattering (SAXS) measurement was 20–30 nm, which was well coincidence with scanning electron microscopy (SEM) results

Poly(styrene- co -styrene sulfonate) (PS-PSS) latexes have been coated with thin overlayer of polyaniline (PANI) to produce electrically conductive ‘core-shell’ particles (PANI/PS-PSS) in the size of range 30–50 nm in diameter. PS-PSS core particles were prepared by radical emulsion copolymerization and PANI was oxidatively polymerized using ammonium peroxydisulfate (APS) on the surface of PS-PSS latex. PANI thin overlayer was observed in transmission electron microscopy (TEM) images indicating polymerization of aniline takes place preferably on the PS-PSS surface rather than in the aqueous bulk phase. Elemental analysis revealed that the weight percent of styrene sulfonate in PS-PSS copolymer was ca. 5.4% and the conductivities of PANI/PS-PSS pellets were greatly increased with the increase of nitrogen content. Thermal gravimetric analysis (TGA) thermograms showed two main degradation stages beginning at 360 and 460°C that correspond to the decomposition of PS-PSS and PANI, respectively.

Conductivity stability at thermal environment of conductive polyaniline-complexes/polyimide (PANI-complexes/PI) blends, which were doped by camphorsulfonic acid (CSA) and dodecylbenzenesulfonic acid (DBSA), respectively, were investigated by conductivity measurements, electron spin resonance (ESR) spectra, differential and scanning thermometer (DSC). In the conversion process of PANI/Polyamic acid (PAA) to PANI/PI, the blend endeavored some kinds of alteration such as decomplexation of moisture and solvent, dissociation of dopant, crosslinking of PANI chain, and the imidization of PAA chain. PANI-DBSA/PI showed higher thermal stability of conductivity than PANI-CSA/PI, and both samples showed nearly linear decay of conductivity with increasing temperature showing greatly enhancement of conductivity stability. When they were exposed at near or over glass transition temperature, the conductivity decay became faster. The conductivity stability at base environment was also higher for PANI-DBSA/PI due to difficulty in accessing of hydroxyl ion to PANI, which were resulted from dopant. DBSA-doped blends showed increased polaron mobility and concentration at relatively high temperature, which led to extremely higher conductivity and its stability at high temperature. Copyright © 2002 John Wiley & Sons, Ltd.

The effect of solvent and dopant on the thermal transition of polyaniline (PANI) has been investigated principally by dynamic mechanical analysis (DMA). Solvent (NMP) containing film was found to exhibit three thermal transitions in tan δ curve (142, 198, and 272°C). The two lower transitions were disappeared when NMP was removed. Hence, the third peak was suggested to be real glass transition of PANI. The shape of DMA spectra was varied with thermal curing temperature, which is directly related to NMP content. Two other peaks seemed to be due to the evaporation of solvent existing as different environment (free NMP and hydrogen-bonded NMP), which was traced by TGA, FT-IR, and DMA with altering the curing temperature. It was suggested that the third peak was composed of cross-linking reaction between adjacent chains as well as glass transition of polyaniline backbone. NMP free films were prepared by two methods (repeating doping–dedoping cycle and thermal curing). In these films, only one tan δ was observed at over 250°C. When the NMP free film was doped, the DMA peak observed over 250°C was broadened and shifted toward lower temperature.

Small-angle X-ray scattering patterns of polyaniline (PANI) complexes/polyimide (PI) blends were observed in order to analyze the compatibility between two components of the blends. From the experimental results, it was concluded that the microphase separation or molecular level mixing, which was the reflection of compatibility, was dependent on the kinds of dopant (camphorsulfonic acid (CSA) and dodecylbenzene sulfonic acid (DBSA)), PANI content and the imidization state. On account of self-assembling nature of PANI–DBSA, PANI–DBSA/poly(amic acid) (PAA) shows phase-separated morphology. On the other hand, PANI–CSA/PAA blends exhibited well-mixed and high compatible morphology. Thermal curing of these blends brought about the change of blend morphology, which was in correlation with altered chain structure from PAA into PI, and was also a function of PANI content. It was supposed that conversion from PAA to PI by thermal curing processes led to enhancement of compatibility probably due to higher interaction between two components.

Polyaniline (PANI) dispersions consisting of 10–20 nm sized nanoparticles were prepared by oxidation with ammonium peroxydisulfate (APS) in sodium dodecylsulfate (SDS) micellar solutions. Coalescence and coagulation were prevented by electrostatic repulsive interaction between anionic SDS micelles. Particle morphology was dependent on the initial shape of surfactant aggregates (micelles) and the molar ratio of SDS to aniline monomer. Spherical particles were obtained at very low monomer concentration and the shape of particles began to be distorted from the spherical shape as monomer concentration increased at constant 0.2 M SDS concentration. The size of spherical particles was the same order of the micellar size or slightly larger. UV–VIS spectroscopy, compositions of PANI powder, morphology, crystalline structure, thermal stability, molecular weight and conductivity of PANI particles synthesized at various monomer and surfactant concentrations were investigated.

Dielectric responses of polyaniline (PANI) salt films, made from two different methods, were compared to investigate the effect of a dopant and film-formation methods on the dielectric properties. One of the film-formation methods for emeraldine salt was the film-doping method, and the other, the solution-doping method. The conductivity relaxation and dielectric properties were measured by a microdielectrometer at 293 K in the frequency range of 1–100,000 Hz. Dielectric spectra were a function of the dopant in the case of the film-doping method, whereas it was a function of solvent–dopant combinations as well as the dopants in the solution-doping method. The dielectric responses of film-doped samples had similar patterns irrespective of the dopants, while those of solution-doped samples were varied, probably due to different conjugation conditions or/and the conduction mechanism. In the case of film-doped samples, dielectric loss and permittivity values were increased with decreasing dopant sizes. The dielectric relaxation times were also varied depending on the kind of dopants. The different solvent–dopant combinations led to variation of the dielectric responses in the solution-doped PANI due to an altered chain structure. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2760–2769, 2001

Chemical oxidative polymerization of aniline was studied in a conventional aqueous solution and in micellar solutions of sodium dodecyl sulfate (SDS, anionic surfactant) and nonylphenol ethoxylate(9) (NP-9, nonionic surfactant) to investigate the effect of molecular structure of surfactants on the polymerization kinetics and particle size. The polymerization kinetics in NP-9 micellar solution were very slow, and this result was explained based on the structural characteristics of surfactant. SDS micellar solutions resulted in a highly transparent solution without any precipitates, whereas some precipitates were visually observed in the NP-9 micellar solution after the reaction finished. The electrical conductivities of polyaniline pellets formed with particles prepared in SDS and NP-9 micellar solutions and aqueous solution showed about 20, 4, and 4 S/cm, respectively. The highest electrical conductivity of particles from SDS micellar solution might be due to the smallest size of particles and the highest...

The changes in protonation level ([N+]/[N] ratio), doping state, and conjugation condition for polyaniline-complexes/polyamic acid (PANI-complexes/PAA) blends and their thermally cured polyaniline-complexes/polyimide (PANI-complexes/PI) have been assessed by X-ray photoelectron spectroscopy and UV–Vis spectroscopy. It was suggested that the protonation levels were predominantly associated with dopants that show different protonation ability. By XPS N1s peak convolution, it was found that thermal treatment of blends led to dedoping when the curing temperature reached 250°C. However, stability of protonation state of blends against thermal curing was higher than pure PANI-complexes. Dopants in the blends also affect the distribution of N+ species and thermal stability to curing. Mild thermal treatment (180°C) led to the increase of conjugation length ascribing to the increased order of polymer chain, although their protonation levels were not increased.

A method had been developed to cast organic/inorganic hybrid composites by sol–gel process. This procedure was mainly controlled by the pH of mixing circumstances of organic/inorganic multicomponent solutions and was attributed to the solvent pH. Cast composite from m-cresol solution could not form a uniform hybrid composite film due to the indistinguishable growth and aggregation of silica at pH 7. But bulk conductivity from m-cresol solution was higher than that from NMP solution, which resulted from the secondary-doping effect of the solvent. These conformational changes of the polymer chain and ability to form hybrid composite film were analyzed by means of Fourier-transform infrared (FTIR), wide-angle X-ray diffraction (WAXD), microdielectrometer, thermogravimetric analysis (TGA), and conductivity measurements.

Conducting films of dodecylbenzenesulfonic (DBSA)-doped polyaniline/polyimide (PANI/PI) blends with various compositions were prepared by solvent casting followed by a thermal imidization process. Electrical and physical properties of the blends were characterized by infrared spectroscopy, an X-ray diffraction technique, thermal analysis, a UV-vis spectrophotometer, a dielectrometer, and conductivity measurements. The blends exhibited a relatively low percolation threshold of electrical conductivity at 5 wt % PANI content and showed higher conductivity than that of pure DBSA-doped PANI when the PANI content exceeded 20 wt %. A lower percolation threshold and a lower compatibility was shown between the two components in the blends than those of PANI–camphorsulfonic acid/polyamic acid (PANI–CSA/PAA). A well-defined layered structure due to the alignment of the long alkyl chain dopant perpendicular to the PANI main chain was evidenced by WAXD spectra. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2169–2178, 1999

By using camphorsulfonic acid (CSA) to protonate polyaniline (PANI), the counterion enabled the PANI–CSA complex processable as a solution phase. So camphorsulfonic acid (CSA)-doped polyaniline/polyimide (PANI/PI) blend films were prepared by the solvent casting method using N-methylpyrrolidinone (NMP) as a cosolvent followed by thermal imidization. The conductivity of the PANI–CSA/PAA (50 wt % PANI content) is greater than that of the pure PANI sample at room temperature. As the thermal imidization proceeded, molecular order of polymer chain structure was improved in the resulting PANI–CSA/PI film due to the annealing effect of PANI chain, and this PANI–CSA/PI film showed higher conductivity than PANI–CSA and PANI–CSA/PAA film. PANI–CSA/PI blend films had a good thermal stability of conductivity at high temperature. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1863–1870, 1998

Butanethiol was used in ultraviolet-initiated thiol-ene reaction with canola and corn oils to produce sulfide-modified vegetable oils (SMVO). The crude SMVO product was successfully purified by solvent extraction, vacuum evaporation, and silica gel chromatography. The SMVO products were characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy. Further product characterization and analysis was conducted using GC and GC-MS on the fatty acid methyl esters obtained by the transesterification of the SMVO products. Investigation of the effect of reaction conditions showed that high yield and high conversion of double bonds into thiol were favored at low reaction temperatures and high butanethiol/vegetable oil ratios. Canola and corn oils gave similar double-bond conversions and yields of the desired SMVO product even though they have big differences in the relative numbers of single and multiple double bonds in their structures. Under best reaction conditions, up to 97% of double-bond conversion and 61% isolated yields of the purified SMVO products were attained.

Nanometre-sized PEDOT-silica core–shell particles were synthesized and self-assembled into crystalline colloidal arrays with a reflection peak in the visible region; these particles were also etched with hydrofluoric acid to produce hollow PEDOT particles.

The color tuning behavior and switching stability of an electrically tunable colloidal photonic crystal system were studied with particular focus on the electrochemical aspects. Photonic color tuning of the colloidal arrays composed of monodisperse particles dispersed in water was achieved using external electric field through lattice constant manipulation. However, the number of effective color tuning cycle was limited due to generation of unwanted ions by electrolysis of the water medium during electrical switching. By introducing larger electrochemical potential window electrodes, such as conductive diamond-like carbon or boron-doped diamond, the switching stability was appreciably enhanced through reducing the number of ions generated.

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We report the tunable photonic crystal behavior of highly concentrated, mildly charged TiO2 nanoparticle colloids under external electric field. Reflectance intensity change at the certain photonic bandgap and its irreversible switching characteristics are observed and discussed. Through computer aided numerical analysis, gradient spacing between charged particles is predicted under electric field, which is well coincidence with experimental results. Also, we report the experimental evidence that the charged nanoparticle can play the role as a major charge carrier in non-aqueous liquid. Its short range moving and stacking on electrode cause the capacitive current flow and charge accumulation like ions in liquid state.

Polyanline (PANI)–silica and poly(3,4-ethylenedioxythiophene) (PEDOT)–silica colloidal composite particles having a diameter of 200–300 nm were synthesized, then converted to intrinsically conducting polymer (ICP)-inks viasolvent exchange. These inks could be inkjet-printed on indium tin oxide-coated poly(ethylene terephthalate) films (ITO-PET film) using a commercial desktop inkjet printer. These PANI–silica or PEDOT–silica/ITO-PET assemblies were utilized as the active layer in electrochromic devices (ECDs). A number of devices were fabricated that exhibited 500 µm size patterning and utilized spatially controlled printing of the particles to allow for a dual image display. In addition, the PANI and PEDOT-based particles were blended into a single ICP ink that allowed for a wider absorption tuning range of the final ECD.

The position and height of the reflection peak of a hydrogel-encapsulated crystalline colloidal array composed of silica particles with a coating of poly(3,4-ethylenedioxythiophene) (PEDOT) could be varied through electrochemical means. This optical tuning was achieved by altering the complex refractive index of the PEDOT shell through a manipulation of its redox state, specifically the absorption characteristics. A mediated electron transfer system was employed to ferry charge from the electrodes of the cell to the isolated particles for both the oxidation and reduction processes. The mediators diffused between the electrode surfaces and the PEDOT-coated particles to accomplish (de)doping of the entire colloidal array. The reflected peak from an ordered array exhibited a significant drop in height during a typical reduction process, dropping to 40% of its original height, though the peak height could be reinstated by re-oxidizing the particles with an imposed bias shift to the cell.

The chemical synthesis of 1-dimensional (1-D) PEDOT nanostructures in the form of tubes, rods, thimbles, and belts has been successfully accomplished through the use of a "hard template".