Understanding the Effects of a High Surface Area Nanostructured Indium Tin Oxide Electrode on Organic Solar Cell Performance.

Organic solar cells (OSCs) are a complex assembly of disparate materials, each with a precise function within the device. Typically, the electrodes are flat, and the device is fabricated through a layering approach of the interfacial layers and photoactive materials. This work explores the integration of high surface area transparent electrodes to investigate the possible role(s) a three-dimensional electrode could take within an OSC, with a BHJ composed of a donor-acceptor combination with a high degree of electron and hole mobility mismatch. Nanotree indium tin oxide (ITO) electrodes were prepared via glancing angle deposition, structures that were previously demonstrated to be single-crystalline. A thin layer of zinc oxide was deposited on the ITO nanotrees via atomic layer deposition, followed by a self-assembled monolayer of C60-based molecules that was bound to the zinc oxide surface through a carboxylic acid group. Infiltration of these functionalized ITO nanotrees with the photoactive layer, the bulk heterojunction comprising PC71BM and a high hole mobility low band gap polymer (PDPPTT-T-TT), led to families of devices that were analyzed for the effect of nanotree height. When the height was varied from 0 to 50, 75, 100, and 120 nm, statistically significant differences in device performance were noted with the maximum device efficiencies observed with a nanotree height of 75 nm. From analysis of these results, it was found that the intrinsic mobility mismatch between the donor and acceptor phases could be compensated for when the electron collection length was reduced relative to the hole collection length, resulting in more balanced charge extraction and reduced recombination, leading to improved efficiencies. However, as the ITO nanotrees increased in height and branching, the decrease in electron collection length was offset by an increase in hole collection length and potential deleterious electric field redistribution effects, resulting in decreased efficiency.

Directed branch growth in aligned nanowire arrays.

Branch growth is directed along two, three, or four in-plane directions in vertically aligned nanowire arrays using vapor-liquid-solid glancing angle deposition (VLS-GLAD) flux engineering. In this work, a dynamically controlled collimated vapor flux guides branch placement during the self-catalyzed epitaxial growth of branched indium tin oxide nanowire arrays. The flux is positioned to grow branches on select nanowire facets, enabling fabrication of aligned nanotree arrays with L-, T-, or X-branching. In addition, a flux motion algorithm is designed to selectively elongate branches along one in-plane axis. Nanotrees are found to be aligned across large areas by X-ray diffraction pole figure analysis and through branch length and orientation measurements collected over 140 µm(2) from scanning electron microscopy images for each array. The pathway to guided assembly of nanowire architectures with controlled interconnectivity in three-dimensions using VLS-GLAD is discussed.

Ultrathin-layer chromatography on SiO(2), Al(2)O(3), TiO(2), and ZrO(2) nanostructured thin films.

We explored four different inorganic oxides and determined their merits in miniaturized planar chromatography. Despite progression of chromatographic techniques over several decades, such alternatives to traditional planar silica gel stationary phases have not been fully evaluated. Glancing angle deposition(GLAD) provided an excellent platform for engineering nanostructured thin films in these materials for ultrathin-layer chromatography (UTLC). Separations of carotenoids and synthetic food dyes were used to investigate the attributes of SiO(2), Al(2)O(3), TiO(2), and ZrO(2)GLAD UTLC media. These anisotropic high surface area thin films possessed similar channel-like features but different chromatographic properties.TiO(2)and ZrO(2)media were especially interesting since analyte retention could be modified through sim-ple oxidation heat treatments and UV irradiation. Generally, oxidation reduced analyte retention while UV exposure increased retention. Changes in retention factor as large as ΔhRF∼ 40 (for Acid Red 14 on titanium oxide) were achieved. Food dye mixtures were applied using consumer inkjet printers as per the Office Chromatography concept and separation performance was quantified using advanced video instrumentation designed for miniaturized plates. Enhanced time-resolved UTLC methods were used to calculate figures of merit from recorded dye separation videos. Small theoretical plate heights (<4 µm)and low limits of detection (<2 ng per zone for the food dye tartrazine) were measured. The combination of engineered GLAD UTLC plates, inkjet application of analyte spots, time-resolved UTLC, and custom analysis algorithms enabled some of the best performance achieved on GLAD UTLC layers. Separations on the inorganic oxide thin films were also successfully hyphenated with electrospray ionization mass spectrometry for the first time. This investigation demonstrates the utility of alternative inorganic oxide GLADUTLC media and probes avenues of expanding the capabilities of miniaturized planar chromatography.

Inkjet application, chromatography, and mass spectrometry of sugars on nanostructured thin films.

Ultrathin-layer chromatography (UTLC) potentially offers faster analysis, reduced solvent and sample volumes, and lower costs. One novel technique for producing UTLC plates has been glancing angle deposition (GLAD), a physical vapor deposition technique capable of aligning macropores to produce interesting separation properties. To date, however, GLAD-UTLC plates have been restricted to model dye systems, rather than realistic analytes. This study demonstrates the transfer of high-performance thin-layer chromatography (HPTLC) sugar analysis methods to GLAD-UTLC plates using the office chromatography framework. A consumer inkjet printer was used to apply very sharp low volume (3-30 nL) bands of water-soluble analytes (lactose, sucrose, and fructose). Analytic performance measurements extrapolated the limits of detection to be 3-5 ng/zone, which was experimentally proven down to 60-70 ng/band, depending on the sugar. This qualitative analysis of sugars in a commercially available chocolate sample is the first reported application of GLAD-UTLC to food samples. The potential utility of GLAD-UTLC is further exemplified by successful coupling with electrospray ionization mass spectrometry for the first time to characterize underivatized sugars.

Transparent anodic TiO2 nanotube arrays on plastic substrates for disposable biosensors and flexible electronics.

Exploitation of anodically formed self-organized TiO2 nanotube arrays in mass-manufactured, disposable biosensors, rollable electrochromic displays and flexible large-area solar cells would greatly benefit from integration with transparent and flexible polymeric substrates. Such integration requires the vacuum deposition of a thin film of titanium on the desired substrate, which is then anodized in suitable media to generate TiO2 nanotube arrays. However the challenges associated with control of Ti film morphology, nanotube array synthesis conditions, and film adhesion and transparency, have necessitated the use of substrate heating during deposition to temperatures of at least 300 degrees C and as high as 500 degrees C to generate highly ordered open-pore nanotube arrays, thus preventing the use of polymeric substrates. We report on a film growth technique that exploits atomic peening to achieve high quality transparent TiO2 nanotube arrays with lengths up to 5.1 microm at room temperature on polyimide substrates without the need for substrate heating or substrate biasing or a Kauffman ion source. The superior optical quality and uniformity of the nanotube arrays was evidenced by the high specular reflectivity and the smooth pattern of periodic interferometric fringes in the transmission spectra of the nanotube arrays, from which the wavelength-dependent effective refractive index was extracted for the air-TiO2 composite medium. A fluorescent immunoassay biosensor constructed using 5.1 microm-long transparent titania nanotube arrays (TTNAs) grown on Kapton substrates detected human cardiac troponin I at a concentration of 0.1 microg ml(-1).

Spectroelectrochemical characterization of small hemoproteins adsorbed within nanostructured mesoporous ITO electrodes.

3D nanostructured transparent indium tin oxide (ITO) electrodes prepared by glancing angle deposition (GLAD) were used for the spectroelectrochemical characterization of cytochrome c (Cyt c) and neuroglobin (Nb). These small hemoproteins, involved as electron-transfer partners in the prevention of apoptosis, are oppositely charged at physiological pH and can each be adsorbed within the ITO network under different pH conditions. The resulting modified electrodes were investigated by UV-visible absorption spectroscopy coupled with cyclic voltammetry. By using nondenaturating adsorption conditions, we demonstrate that both proteins are capable of direct electron transfer to the conductive ITO surface, sharing apparent standard potentials similar to those reported in solution. Preservation of the 3D protein structure upon adsorption was confirmed by resonance Raman (rR) spectroscopy. Analysis of the derivative cyclic voltabsorptograms (DCVA) monitored either in the Soret or the Q bands at scan rates up to 1 V s(-1) allowed us to investigate direct interfacial electron transfer kinetics. From the DCVA shape and scan rate dependences, we conclude that the interaction of Cyt c with the ITO surface is more specific than Nb, suggesting an oriented adsorption of Cyt c and a random adsorption of Nb on the ITO surface. At the same time, Cyt c appears more sensitive to the experimental adsorption conditions, and complete denaturation of Cyt c may occur as evidenced from cross-correlation of rR spectroscopy and spectroelectrochemistry.

Dry etching of copper phthalocyanine thin films: effects on morphology and surface stoichiometry.

We investigate the evolution of copper phthalocyanine thin films as they are etched with argon plasma. Significant morphological changes occur as a result of the ion bombardment; a planar surface quickly becomes an array of nanopillars which are less than 20 nm in diameter. The changes in morphology are independent of plasma power, which controls the etch rate only. Analysis by X-ray photoelectron spectroscopy shows that surface concentrations of copper and oxygen increase with etch time, while carbon and nitrogen are depleted. Despite these changes in surface stoichiometry, we observe no effect on the work function. The absorbance and X-ray diffraction spectra show no changes other than the peaks diminishing with etch time. These findings have important implications for organic photovoltaic devices which seek nanopillar thin films of metal phthalocyanine materials as an optimal structure.

Enhancement in broadband and quasi-omnidirectional antireflection of nanopillar arrays by ion milling.

A new technique is developed to fabricate biomimetic antireflection coatings (ARCs). This technique combines a bottom-up fabrication approach (glancing angle deposition, or GLAD) with a top-down engineering process (ion milling). The GLAD technique is first utilized to produce nanopillar arrays (NPAs) with broadened structures, which are subsequently transformed into biomimetic tapered geometries by means of post-deposition ion milling. This structure transformation, due to milling-induced mass redistribution, remarkably decreases reflection over a wide wavelength range (300-1700 nm) and field of view (angle of incidence < 60° with respect to the substrate normal). The milling-induced antireflection enhancement has been demonstrated in the NPAs made of Si, SiO(x) and TiO(2), illustrating that this integrated technique is readily adapted to a wide variety of materials. Good agreement between simulation and experiment indicates that the enhanced antireflection performance is ascribed to a smoother refractive index transition from the substrate to the air, which improves the impedance match and reduces reflection losses. Additionally, ion bombardment tends to alter the stoichiometry and diminish the crystallographic structure of the NPA materials. The broadband and quasi-omnidirectional antireflection observed establishes the strong competitiveness of this technique with the methods previously reported.

Unraveling the mechanism of catalytic reduction of O2 by microperoxidase-11 adsorbed within a transparent 3D-nanoporous ITO film.

Nanoporous films of indium tin oxide (ITO), with thicknesses ranging from 250 nm to 2 µm, were prepared by Glancing Angle Deposition (GLAD) and used as highly sensitive transparent 3D-electrodes for quantitatively interrogating, by time-resolved spectroelectrochemistry, the reactivity of microperoxidase-11 (MP-11) adsorbed within such films. The capacitive current densities of these 3D-electrodes as well as the amount of adsorbed MP-11 were shown to be linearly correlated to the GLAD ITO film thickness, indicating a homogeneous distribution of MP-11 across the film as well as homogeneous film porosity. Under saturating adsorption conditions, MP-11 film concentration as high as 60 mM was reached. This is equivalent to a stack of 110 monolayers of MP-11 per micrometer film thickness. This high MP-11 film loading combined with the excellent ITO film conductivity has allowed the simultaneous characterization of the heterogeneous one-electron transfer dynamics of the MP-11 Fe(III)/Fe(II) redox couple by cyclic voltammetry and cyclic voltabsorptometry, up to a scan rate of few volts per second with a satisfactory single-scan signal-to-noise ratio. The potency of the method to unravel complex redox coupled chemical reactions was also demonstrated with the catalytic reduction of oxygen by MP-11. In the presence of O(2), cross-correlation of electrochemical and spectroscopic data has allowed us to determine the key kinetics and thermodynamics parameters of the redox catalysis that otherwise could not be easily extracted using conventional protein film voltammetry. On the basis of numerical simulations of cyclic voltammograms and voltabsorptograms and within the framework of different plausible catalytic reaction schemes including appropriate approximations, it was shown possible to discriminate between different possible catalytic pathways and to identify the relevant catalytic cycle. In addition, from the best fits of simulations to the experimental voltammograms and voltabsorptograms, the partition coefficient of O(2) for the ITO film as well as the values of two kinetic rate constants could be extracted. It was finally concluded that the catalytic reduction of O(2) by MP-11 adsorbed within nanoporous ITO films occurs via a 2-electron mechanism with the formation of an intermediate Fe(III)-OOH adduct characterized by a decay rate of 11 s(-1). The spectroelectroanalytical strategy presented here opens new opportunities for characterizing complex redox-coupled chemical reactions not only with redox proteins, but also with redox biomimetic systems and catalysts. It might also be of great interest for the development and optimization of new spectroelectrochemical sensors and biosensors, or eventually new photoelectrocatalytic systems or biofuel cells.

C60 fullerene nanocolumns--polythiophene heterojunctions for inverted organic photovoltaic cells.

Inverted organic photovoltaic cells have been fabricated based on vertical C(60) nanocolumns filled with spin-coated poly[3-(4-carboxybutyl)thiophene-2,5-diyl] (P3CBT). These C(60) nanocolumns were prepared via glancing angle deposition (GLAD), an efficient synthetic approach that controls the morphology of the resulting film, including intercolumn spacing, nanostructure shapes, and overall film thickness, among others. Intercolumn spacing was tuned to better match the expected P3CBT exciton diffusion length while simultaneously increasing heterointerface area. Due to observed in situ dissolution of the C(60) nanocolumns in solvents typically used to spin-coat polythiophene-based polymers (i.e., chloroform and chlorobenzene), the carboxylic acid-substituted polythiophene, P3CBT, was used as it is soluble in dimethyl sulfoxide (DMSO), a solvent that did not affect the structure of the GLAD-produced C(60) nanostructures. Preservation of the C(60) nanocolumnar structure in the presence of DMSO, with and without P3CBT, was verified by absorbance spectroscopy and SEM imaging. Incorporating these nanostructured C(60)/P3CBT films into photovoltaic devices on indium tin oxide (ITO) showed that the engineered nanomorphology yielded a 5-fold increase in short-circuit current and a power conversion efficiency (PCE) increase from (0.2 ± 0.03)% to (0.8 ± 0.2)% when compared to a planar device. When compared to a standard bulk heterojunction (BHJ) device based upon the same materials, the C(60)-GLAD device outperformed fully solution-processed bulk heterojunctions, which were observed to have PCEs of (0.49 ± 0.03)%.

Microchannels filled with diverse micro- and nanostructures fabricated by glancing angle deposition.

The integration of porous structures into microchannels is known to enable unique and useful separations both in electrophoresis and chromatography. Etched pillars and other nanostructures have received considerable interest in recent years as a platform for creating microchannels with pores tailored to specific applications. We present a versatile method for integration of three-dimensionally sculptured nano- and micro-structures into PDMS microchannels. Glancing angle deposition was used to fabricate nanostructures that were subsequently embedded in PDMS microchannels using a sacrificial resist process. With this technique, an assortment of structures made from a wide selection of materials can be integrated in PDMS microchannels; some examples of this versatility, including chiral and chevron nanostructures, are demonstrated. We also present a working device made using this process, separating 6/10/20 kbp and 10/48 kbp DNA mixtures in a DNA fractionator containing GLAD-deposited SiO(2) vertical posts as the separating medium. The separation mechanism was verified to resemble that found in prior fractionation devices, using total internal reflection fluorescence microscopy. GLAD fabrication enables insertion of three-dimensional structures into microchannels that cannot be fabricated with any existing techniques, and this versatility in structural design could facilitate new developments in on-chip separations.

Indium tin oxide nanopillar electrodes in polymer/fullerene solar cells.

Using high surface area nanostructured electrodes in organic photovoltaic (OPV) devices is a route to enhanced power conversion efficiency. In this paper, indium tin oxide (ITO) and hybrid ITO/SiO(2) nanopillars are employed as three-dimensional high surface area transparent electrodes in OPVs. The nanopillar arrays are fabricated via glancing angle deposition (GLAD) and electrochemically modified with nanofibrous PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(p-styrenesulfonate)). The structures are found to have increased surface area as characterized by porosimetry. When applied as anodes in polymer/fullerene OPVs (architecture: commercial ITO/GLAD ITO/PEDOT:PSS/P3HT:PCBM/Al, where P3HT is 2,5-diyl-poly(3-hexylthiophene) and PCBM is [6,6]-phenyl-C(61)-butyric acid methyl ester), the air-processed solar cells incorporating high surface area, PEDOT:PSS-modified ITO nanoelectrode arrays operate with improved performance relative to devices processed identically on unstructured, commercial ITO substrates. The resulting power conversion efficiency is 2.2% which is a third greater than for devices prepared on commercial ITO. To further refine the structure, insulating SiO(2) caps are added above the GLAD ITO nanopillars to produce a hybrid ITO/SiO(2) nanoelectrode. OPV devices based on this system show reduced electrical shorting and series resistance, and as a consequence, a further improved power conversion efficiency of 2.5% is recorded.

Time-resolved UV-visible spectroelectrochemistry using transparent 3D-mesoporous nanocrystalline ITO electrodes.

Efficient and rapid adsorption of microperoxidase 11 within a highly porous ITO thin film (200 nm) prepared by glancing angle deposition was achieved. Adsorbed redox molecules were reversibly and rapidly reduced throughout the 3D-conductive matrix in ca. 50 ms, allowing the heterogeneous electron transfer rate to be determined by derivative cyclic voltabsorptometry.

Taking a little off the top: nanorod array morphology and growth studied by focused ion beam tomography.

The high surface area, large aspect ratio, and porous nature of nanorod arrays make them excellent foundation materials for many devices. Of the many synthesis techniques for forming nanorods, glancing angle deposition (GLAD) offers one of the more straightforward and flexible methods for ensuring control of alignment, porosity, and architecture of the nanorods. Here we demonstrate the first use of a dual-beam (focused ion beam (FIB) combined with scanning electron microscopy (SEM)) instrument to section and image the internal morphology of a nanorod array fabricated using the GLAD technique. We have used the FIB-SEM to reconstruct the 3D composition of TiO(2) nanorods, allowing us to visualize for the first time the core structures of many potential devices. We have also been able to probe the relationship between critical parameters such as diameter (w(act)), internanorod spacing (ν(act)), center-to-center spacing (c(act)), and nanorod population density (d(act)) and the depth of the nanocolumn (t) for a single homogeneous structure. A continuous data set was obtained from a single 5-µm-thick GLAD film, avoiding the artifacts arising from the analysis of the top surfaces of multiple samples of varying thicknesses. An analysis of the acquired sectioned data has allowed us to determine that the critical nanocolumn parameters follow a power-law scaling trend with w(act) = 9.4t(0.35) nm, ν(act) = 15.2t(0.25) nm, c(act) = 24.8t(0.31) nm, and d(act) = 3402t(-0.65) columns µm(-2). Using the FIB/SEM images acquired for the TiO(2) nanorods, we have also investigated the evolution of individual nanocolumns and have observed that bifurcation and branching play a significant role in the extinction or survival of these nanorods. These findings will allow for the optimization of nanorod properties for device applications. Also, the FIB sectioning and reconstruction process developed here will permit for the investigation of nanorod arrays formed from a range of synthesis techniques and materials.

Coupled defects in one-dimensional photonic crystal films fabricated with glancing angle deposition.

This work presents the successful fabrication of 1D photonic crystals (PCs) with two defects using the glancing angle deposition (GLAD) technique. We study the coupling behavior of the two PC defects and demonstrate the ability to control the defect interaction. GLAD allows engineering of film nanostructure to produce PCs with sinusoidal refractive index variation through control of film nanostructure and porosity. Two phase-shift defects are introduced into the refractive index profile of the film. The observed defect-defect coupling is explained by a coupled-oscillator model and the interaction strength is found to decrease exponentially with increasing defect separation. Furthermore, the results demonstrate the promise of GLAD as a platform technology for PC research and device fabrication.

Matrix-free laser desorption/ionization mass spectrometry using silicon glancing angle deposition (GLAD) films.

Glancing angle deposition (GLAD) was used to fabricate nanostructured silicon (Si) thin films with highly controlled morphology for use in laser desorption/ionization mass spectrometry (DIOS-MS). Peptides, drugs and metabolites in the mass range of 150-2500 Da were readily analyzed. The best performance was obtained with 500 nm thick films deposited at a deposition angle of 85 degrees . Low background mass spectra and attomole detection limits were observed with DIOS-MS for various peptides. Films used after three months of dry storage in ambient conditions produced mass spectra with negligible low-mass noise following a 15 min UV-ozone treatment. The performance of the Si GLAD films was as good as or better than that reported for electrochemically etched porous silicon and related materials, and was superior to matrix-assisted laser desorption/ionization (MALDI)-MS for analysis of mixtures of small molecules between 150-2500 Da in terms of background chemical noise, detection limits and spot-to-spot reproducibility. The spot-to-spot reproducibility of signal intensities (100 shots/spectrum) from 21 different Si GLAD film targets was +/-13% relative standard deviation (RSD). The single shot-to-shot reproducibility of signals on a single target was +/-19% RSD (n = 7), with no indication of sweet spots or mute spots.

Electrostatic layer-by-layer assembly of CdSe nanorod/polymer nanocomposite thin films.

Electrostatic layer-by-layer assembly was the basis for the synthesis of multilayer nanorod/polymer composite films. Cationic and water-soluble CdSe nanorods (NRs) were synthesized and partnered with anionic polymers including poly(sodium 4-styrenesulfonate) (PSS) and two polythiophene-based photoactive polymers, sodium poly[2-(3-thienyl)-ethoxy-4-butylsulfonate (PTEBS) and poly[3-(potassium-6-hexanoate)thiophene-2,5-diyl] (P3KHT). Controlled multilayer growth is shown through UV-vis spectroscopy, cross-sectional SEM and surface analytical techniques including atomic force microscopy. The formation of an intimate nanorod/conducting polymer bulk heterojunction is confirmed through cross-sectional SEM, TEM, and scanning Auger analysis. A series of photovoltaic devices was fabricated on ITO electrodes using CdSe NRs in combination with PTEBS or P3KHT. A thorough device analysis showed that performance was limited by low short circuit current although charge transfer was confirmed in the ELBL nanocomposite thin films.

Miniaturized planar chromatography using office peripherals.

High-performance thin-layer chromatography is a separation technique commonly used to identify and quantify components in chemical mixtures. Sophisticated analytical tools are required to extract the full analytical power from this technique and especially for miniaturized planar chromatography its utility has not been harnessed. A new approach uses an elegant, simplified system assembled from ordinary consumer printers and scanners to perform separations on monolithic and nanostructured ultrathin-layer phases. This system is shown to outperform existing planar chromatographic tools for analysis on miniaturized plates. Analysis can be completed in a manner of minutes, running numerous samples in parallel at a reduced cost, with very low sample and reagent volumes, all using a familiar computer interface with common office peripherals.

Surface area characterization of obliquely deposited metal oxide nanostructured thin films.

The glancing angle deposition (GLAD) technique is used to fabricate nanostructured thin films with high surface area. Quantifying this property is important for optimizing GLAD-based device performance. Our group has used high-sensitivity krypton gas adsorption and the complementary technique of cyclic voltammetry to measure surface area as a function of deposition angle, thickness, and morphological characteristics for several metal oxide thin films. In this work, we studied amorphous titanium dioxide (TiO(2)), amorphous silicon dioxide (SiO(2)), and polycrystalline indium tin oxide (ITO) nanostructures with vertical and helical post morphologies over a range of oblique deposition angles from 0 to 86 degrees. Krypton gas sorption isotherms, evaluated using the Brunauer-Emmettt-Teller (BET) method, revealed maximum surface area enhancements of 880 +/- 110, 980 +/- 125, and 210 +/- 30 times the footprint area (equivalently 300 +/- 40, 570 +/- 70, and 50 +/- 6 m(2) g(-1)) for vertical posts TiO(2), SiO(2), and ITO. We also applied the cyclic voltammetry technique to these ITO films and observed the same overall trends as seen with the BET method. In addition, we applied the BET method to the measurement of helical films and found that the surface area trend was shifted with respect to that of vertical post films. This revealed the important influence of the substrate rotation rate and film morphology on surface properties. Finally, we showed that the surface area scales linearly with film thickness, with slopes of 730 +/- 35 to 235 +/- 10 m(2) m(-2) microm(-1) found for titania vertical post films deposited at angles from 70 to 85 degrees. This characterization effort will allow for the optimization of solar, photonic, and sensing devices fabricated from thin metal oxide films using GLAD.

Thienylsilane-modified indium tin oxide as an anodic interface in polymer/fullerene solar cells.

The generation and characterization of a robust thienylsilane molecular layer on indium tin oxide substrates was investigated. The molecular layer was found to reduce the oxidation potential required for the electrochemical polymerization of 3,4-ethylenedioxythiophene. The resulting electrochemically prepared poly(3,4-ethylenedioxythiophene):poly(p-styrenesulfonate) (ePEDOT:PSS) films were found to be more uniform in coverage with lower roughness and higher conductivity than analogous films fabricated with bare ITO. A relative improvement in the efficiency of 2,5-diyl-poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) bulk heterojunction solar cells was observed when devices were formed on thienylsilane-modified ITO electrodes, rather than unmodified ITO control electrodes.