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Solar photoelectrolysis of water is considered as a promising route towards green hydrogen production. Since its first demonstration in 1969 [1], improving the efficiency of the process remains the major challenge. Current research efforts focus on the development of improved photoelectrodes enabling higher photocurrents and larger solar-to-hydrogen conversion. Of special interest are photoactive semiconductors being used as photoanodes. Employing concepts of nanostructuring and doping combined with liquid phase technologies for constructing favorable layered configurations, metal oxides offer strategic advantages when it comes towards the use of abundant non-critical materials and sustainable fabrication of efficient large-area photoanodes. Deeper comprehension of the underlying photoelectrochemical processes provides the necessary feedback to a successful progress. In this presentation, boron-doped nanostructured TiO2 film electrodes are used as photoanode. We show that its photoelectrochemical performance can be successfully described by mathematical and physical models. This finding is of wider general interest to understand and improve the performance of nanostructured layered photoanode architectures.

Hydrogen is considered as one of the most suitable alternatives to fossil fuels if produced from water using renewable resources. Particularly, photoelectrochemical (PEC) water splitting is a well-known technology that allows to obtain green hydrogen through a combination of electricity and sunlight. This process requires photoelectrodes composed of a conductive substrate and a photoactive phase. The present work demonstrates that singlewalled carbon nanotubes (SWCNTs) can be processed along with nanocellulose, a biocompatible adjuvant that enables waterborne inks, into conductive films [1]. SWCNT inks were spray-coated over glass substrates in the form of films. Their low electrical resistivity values (Figure 1a) highlight that SWCNT films are valuable alternatives to typically employed opaque substrates in electrochemical devices, such as pyrolytic graphite. Subsequently, a TiO2 layer was deposited onto the SWCNT films, thus rendering the desired photoanodes (Figure 1b). Electrochemical measurements show that the as-prepared photoanodes display a noticeable photocurrent (Figure 1c), being a clear indicative of their water splitting activity. This is an unprecedented feature for this type of electrode configuration.

Here, the alpha amino acid l-alanine is employed as both a capping and stabilizing agent in the aqueous synthesis of submicron-sized metallic copper particles under ambient atmospheric conditions. The reduction of the copper(II) precursor is achieved using l-ascorbic acid (vitamin C) as the reducing agent. The nature of the complex formed between l-alanine and the copper(II) precursor, pH of the medium, temperature, and the relative proportion of capping agent are found to play a significant role in determining the size, shape, and oxidative stability of the resulting particles. The adsorbed l-alanine is shown to act as a barrier imparting excellent thermal stability to capped copper particles, delaying the onset of temperature-induced aerial oxidation. The stability of the particles is complemented by highly favorable sintering conditions, rendering the formation of conductive copper films at significantly lower temperatures (T ≤ 120 °C) compared to alternative preparation methods. The resulting copper films are well-passivated by residual surface l-alanine molecules, promoting long-term stability without hindering the surface chemistry of the copper film as evidenced by the catalytic activity. Contrary to the popular belief that ligands with long carbon chains are best for providing stability, these findings demonstrate that very small ligands can provide highly effective stability to copper without significantly deteriorating its functionality while facilitating low-temperature sintering, which is a key requirement for emerging flexible electronic applications.

Commercial methods for the production of green hydrogen are based on alkaline or proton exchange membrane (PEM) electrolysis. Several alternatives are being investigated, including photo-electrochemical water splitting. At a laboratory scale, working electrodes are tipically assembled on ITO of FTO transparent conducting films. Those substrates could be substituted by cheaper more abundant materials. Therefore, we fabricated opaque films of carbon nanotubes (CNTs) to be probed as supports for a photo-active semiconductive oxide, namely nanoparticulate TiO2. Aqueous dispersions of single-walled and multi-walled CNTs were prepared by sonication or stirring in a surfactant (SDBS). The inks were utilized to fabricate conducting electrodes by ultrasounds-assisted spraycoating on glass substrates. Nanoparticulate TiO2 (Aeroxide P25) was deposited on the CNT films by spray-coating of isopropanol suspensions. The TiO2/CNT electrodes were tested in a transient photocurrent experiment in 0.1M Na2SO4 at 0.4V vs. Ag/AgCl. A large capacitance contribution was detected because of CNTs. However, it was clearly demonstrated that an anodic photocurrent is generated under irradiation with a solar simulator (~300 mW·cm-2). While the obtained photocurrents were small ( a few µA·cm-2), the way is open to optimize new architectures for PEC hydrogen generation.

We present a novel approach for deposition of metallic silver films from silver nitrate (AgNO₃) ink. The conversion of AgNO₃ is induced by argon plasma of the diffuse coplanar surface barrier discharge (DCSBD) generated at atmospheric pressure. The macroscopically homogeneous and diffuse plasma of high power density allows fast reduction of AgNO₃ into conductive metallic silver within two minutes. The process is carried out at temperatures below 70 °C and without the need for a complex vacuum chamber and is therefore highly suitable for deposition onto temperature-sensitive materials. In our study we used paper prepared from nanocellulose fibres, which offers mechanical flexibility, translucency and recyclability while having lower surface roughness and enhanced mechanical properties and thermal stability compared to regular paper. As a figure of merit, the resistivity of prepared films was measured. The X-ray photoelectron spectroscopy was used to study the conversion of AgNO₃ into metallic silver. Scanning electron microscopy revealed the morphology of the surface of the films giving insight on the nucleation and the growth process. The silver films prepared according to our methodology are an attractive possibility for applications in sensing devices or as conductive lines and other features in flexible electronics.

[EN] The most widely used method to disperse carbon nanotubes in aqueous media is through the application of ultrasounds. However, there are studies that indicate that it has certain drawbacks such as the shortening of nanotubes, as well as causing structural damage [10]. It is possible to disperse carbon nanotubes in aqueous media by stirring for a long time (Lukasczuk et al, 2010) [1]. In this research, a study has been carried out in which dispersions of SWCNT (Single-Walled Carbon Nanotubes) and MWCNT (Multi-Walled Carbon Nanotubes) have been prepared by the ultrasound and the stirring method, characterized and compared. The method of preparing dispersions of carbon nanotubes in an aqueous media by stirring has been found to be successful in obtaining stable dispersions with a high degree of dispersed nanotubes. In the comparison between both methods, it was observed that the SWCNTs showed similar dispersibility values, while the MWCNTs prepared by stirring showed a somewhat worse dispersibility compared to the ultrasound method. However, the viscosity study indicated that the stirring method would be less invasive and would allow dispersions with nanotubes of a higher aspect ratio (ratio between the length of the nanotube and the diameter). Once the dispersions had been studied, they were used as "inks" to make conductive films on glass, which were subsequently used as a support for the preparation of titanium dioxide electrodes. Finally, with the titanium oxide electrodes that were prepared, a photoelectrochemical experiment was carried out irradiating the electrode with a laboratory solar simulator. In this experiment, it was found that all the prepared electrodes showed a certain degree of photoactivity., [ES] El método más utilizado para dispersar nanotubos de carbono en medios acuosos es a través de la aplicación de ultrasonidos. Sin embargo, existen estudios que indican que este método presenta ciertos inconvenientes como el acortamiento de los nanotubos, así como daño estructural [10]. Resulta posible dispersar nanotubos de carbono en medios acuosos mediante agitación durante un tiempo prolongado (Lukasczuk et al, 2010) [1]. En este trabajo se ha realizado un estudio en el que se han caracterizado y comparado dispersiones de nanotubos de carbono del tipo SWCNT (Single-Walled Carbon Nanotubes) y del tipo MWCNT (Multi-Walled Carbon Nanotubes) realizadas mediante el método de ultrasonidos y el método agitación. Se ha demostrado que el método de preparación de dispersiones de nanotubos de carbono en un medio acuoso mediante agitación resulta satisfactorio para obtener dispersiones estables con un alto grado de nanotubos en dispersión. En la comparativa entre ambos métodos, se observó que los SWCNT mostraron valores similares de dispersabilidad, mientras que los MWCNT preparados por agitación mostraron una dispersabilidad algo peor en comparación con el método de ultrasonidos. No obstante, el estudio de viscosidad indicó que el método de agitación sería menos invasivo y permitiría obtener dispersiones con nanotubos con una mayor relación de aspecto (relación entre la longitud del nanotubo y el diámetro). Una vez estudiadas las dispersiones, fueron empleadas a modo de “tintas” para elaborar películas conductoras sobre vidrio, las cuales se usaron como soporte para la preparación de electrodos el óxido de titanio. Finalmente, con los electrodos de óxido de titanio que se prepararon se realizó un experimento fotoelectroquímico irradiando con un simulador solar de laboratorio. En este experimento se pudo comprobar que todos los electrodos preparados mostraron un cierto grado de fotoactividad.

Carbon nanotubes (CNTs) processed into conductive films by liquid phase deposition technologies reveal increasing interest as electrode components in electrochemical device platforms for sensing and energy storage applications. In this work we show that the addition of acrylic latex to water-based CNT inks not only favors the fabrication of stable and robust flexible electrodes on plastic substrates but, moreover, sensitively enables the control of their electrical and electrochemical transport properties. Importantly, within a given concentration range, the acrylic additive in the films, being used as working electrodes, effectively blocks undesired faradaic transfer reactions across the electrode–electrolyte interface while maintaining their capacitance response as probed in a three-electrode electrochemical device configuration. Our results suggest a valuable strategy to enhance the chemical stability of CNT film electrodes and to suppress non-specific parasitic electrochemical reactions of relevance to electroanalytical and energy storage applications.

Conductive inks development is currently a field of study for electronic applications, including energy devices and sensors, where metal nanoparticles (MNPs) have most commonly been used. However, MNPs present important disadvantages, typically the scarcity of noble metals (Au, Ag, Pt) and the easy oxidation of the rest (Cu, Al). Carbon nanomaterials, such as single-walled carbon nanotubes (SWCNTs), are regarded as an alternative for the fabrication of conductive inks, because of their properties: electronic and thermal conductivity, 1D structure, surface functionalization, and the dispersion in many surfactants and some organic solvents, which are unfortunately highly toxic and unsustainable.1 New biofriendly and sustainable dispersing agents are on demand, and also the use of water as the liquid medium for conductive inks. Nanocellulose, an emerging 'green' nanomaterial, posseses many desirable features: hydrophilicity, sustainability, abundance and exellent performance as dispersing agent, which makes it a promising candidate as an alternative to toxic surfactants and hazardous organic solvents. 2 Herein, we report the facile, non-toxic and environmentally friendly fabrication of aqueous and stable conductive inks made up of SWCNTs, using nanocrystalline cellulose as dispersant agent. 3 The conductive ink was deposited by optimized spray coating techniques to fabricate the thin films, which were characterized in terms of electrical properties.

In the present work, the most recent progress in our laboratories will be presented, regarding the synthesis, characterization and applications of conductive inks made with carbon nanostructures (carbon nanotubes and graphene derivatives). Our main approach is to develop aqueous systems, capable of acting as precursors of conductive thin films, under a sustainability scope, by employing 'green' nanomaterials as dispersing agents coming from renewable sources. The main focuses are cellulose or chitin nanocrystals, and silk fibroin, which are able to generate stable aqueous bioinks in combination with carbon nanomaterials and several processing techniques (namely, dispersion, centrifugation or autoclave treatments). The processing, characterization and use of these inks will be discussed, as well as some application aspects in the energy and biomedicine fields.

The development of contuctive inks is currently an active field of study for electronic applications in devices such as sensors or electrodes, where Metal Nanoparticles (MNPs) have tradicionally been the target for this purpose. However, this kind of nanomaterials present important disadvantages in their use, such as the high cost of noble metals (Au, Ag, Pt) and the easy oxidation of the cheaper ones (Cu, Al). Carbon Nanomaterials, such as single-walled carbon nanotubes (SWCNTs) are regarded as a good alternative to the former nanomaterials for the generation of conductive inks, due to their electronic properties, and the easy dispersion in many surfactants and some organic solvents, which are unfortunately highly toxic and unsustainable.1 New dispersing agents, biofriendly and sustainable are on demand, and also the use of water as solvent for conductive inks. Nanocellulose, a new emerging ‘green’ nanomaterial posseses many desirable features: hydrophilicity, sustainability, abundance and exellent performance as dispersing agent, which makes it a promising candidate as an alternative to toxic surfactants and hazardous organic solvents.2 Herein, we report the facile, non-toxic and environmentally friendly fabrication of aqueous contuctive inks made up of SWCNTs, and using nanocrystalline cellulose as dispersant agent (Figure 1). The conductive films generated with these inks will be studied in terms of electrical properties.

In this paper, conductive composite films were synthetized based on oxidized cellulosic nanofibres (CNFo), 1-(2-cyanoethyl)pyrrole and pyrrole. The 1-(2-cyanoethyl)pyrrole was reduced into N-(3-aminopropyl)pyrrole before being grafted on carboxyl groups of CNFo. Oxidative polymerization of polypyrrole (Ppy) was conducted in an iron(III) chloride (FeCl3) solution, onto the N-(3-aminopropyl)pyrrole grafted. The resulting composite films were characterized by FTIR-ATR Spectroscopy, scanning electron microscopy (SEM) equipped with energy-dispersive x-ray spectroscopy (EDX), tensile strength measurement, thermogravimetric analysis (TGA), wettability and electrical conductivity measurements. The grafting of 1-(2-cyanoethyl)pyrrole played a leading role in improving these properties by increasing potential connections between chains of conducting polymer and cellulose fibres. The outcomes show that the PPy nanoparticles coating on the grafted films increase a lot of characteristics of our composite such as wettability, mechanical properties, thermal protection and more importantly the electrical conductivity which was improved by a 10E5 factor in comparison to the uncoated films. In this condition, this nanostructure could be considered in the design of high-performance electrodes for supercapacitor, battery and sensor applications. © 2016 Elsevier B.V.

In this paper, conductive composite films were synthetized based on oxidized cellulosic nanofibres (CNFo), 1-(2-cyanoethyl)pyrrole and pyrrole. The 1-(2-cyanoethyl)pyrrole was reduced into N-(3-aminopropyl)pyrrole before being grafted on carboxyl groups of CNFo. Oxidative polymerization of polypyrrole (Ppy) was conducted in an iron(III) chloride (FeCl3) solution, onto the N-(3-aminopropyl)pyrrole grafted. The resulting composite films were characterized by FTIR-ATR Spectroscopy, scanning electron microscopy (SEM) equipped with energy-dispersive x-ray spectroscopy (EDX), tensile strength measurement, thermogravimetric analysis (TGA), wettability and electrical conductivity measurements. The grafting of 1-(2-cyanoethyl)pyrrole played a leading role in improving these properties by increasing potential connections between chains of conducting polymer and cellulose fibres. The outcomes show that the PPy nanoparticles coating on the grafted films increase a lot of characteristics of our composite such as wettability, mechanical properties, thermal protection and more importantly the electrical conductivity which was improved by a 10E5 factor in comparison to the uncoated films. In this condition, this nanostructure could be considered in the design of high-performance electrodes for supercapacitor, battery and sensor applications. © 2016 Elsevier B.V.

In this paper, conductive composite films were synthetized based on oxidized cellulosic nanofibres (CNFo), 1-(2-cyanoethyl)pyrrole and pyrrole. The 1-(2-cyanoethyl)pyrrole was reduced into N-(3-aminopropyl)pyrrole before being grafted on carboxyl groups of CNFo. Oxidative polymerization of polypyrrole (Ppy) was conducted in an iron(III) chloride (FeCl3) solution, onto the N-(3-aminopropyl)pyrrole grafted. The resulting composite films were characterized by FTIR-ATR Spectroscopy, scanning electron microscopy (SEM) equipped with energy-dispersive x-ray spectroscopy (EDX), tensile strength measurement, thermogravimetric analysis (TGA), wettability and electrical conductivity measurements. The grafting of 1-(2-cyanoethyl)pyrrole played a leading role in improving these properties by increasing potential connections between chains of conducting polymer and cellulose fibres. The outcomes show that the PPy nanoparticles coating on the grafted films increase a lot of characteristics of our composite such as wettability, mechanical properties, thermal protection and more importantly the electrical conductivity which was improved by a 10E5 factor in comparison to the uncoated films. In this condition, this nanostructure could be considered in the design of high-performance electrodes for supercapacitor, battery and sensor applications. © 2016 Elsevier B.V.

A new manufacturing paradigm may lower the cost and environmental impact of existing products, as well as enable completely new products. Large scale, roll-to-roll manufacturing of flexible electronics and other functionality has great potential. However, a commercial breakthrough depends on a lower consumption of materials and energy compared with competing alternatives, and that sufficiently high performance and reliability of the products can be maintained. The substrate constitutes a large part of the product, and therefore its cost and environmental sustainability are important. Electrically conducting thin films are required in many functional devices and applications. In demanding applications, metal films offer the highest conductivity. In this thesis, paper substrates of various type and construction were characterized, and the characteristics were related to the performance of inkjet-printed metal patterns. Fast absorption of the ink carrier was beneficial for well-defined pattern geometry, as well as high conductivity. Surface roughness with topography variations of sufficiently large amplitude and frequency, was detrimental to the pattern definition and conductivity. Porosity was another important factor, where the characteristic pore size was much more important than the total pore volume. Apparent surface energy was important for non-absorbing substrates, but of limited importance for coatings with a high absorption rate. Applying thin polymer–based coatings on flexible non-porous films to provide a mechanism for ink solvent removal, improved the pattern definition significantly. Inkjet-printing of a ZnO-dispersion on uncoated paper provided a thin spot-coating, allowing conductivity of silver nanoparticle films. Conductive nanoparticle films could not form directly on the uncoated paper. The resulting performance of printed metal patterns was highly dependent on a well adapted sintering methodology. Several sintering methods were examined in this

Well-ordered 3D mesoporous indium tin oxide (ITO) films obtained by a templated sol-gel route are discussed as conductive porous current collectors. This paper explores the use of such films modified by electrochemical deposition of zinc oxide (ZnO) on the pore walls to improve the electron transport in dye-sensitized solar cells (DSSCs). Mesoporous ITO film were dip-coated with pore sizes of 20-25 nm and 40-45 nm employing novel poly(isobutylene)-b-poly(ethylene oxide) block copolymers as structure-directors. After electrochemical deposition of ZnO and sensitization with the indoline dye D149 the films were tested as photoanodes in DSSCs. Short ZnO deposition times led to strong back reaction of photogenerated electrons from non-covered ITO to the electrolyte. ITO films with larger pores enabled longer ZnO deposition times before pore blocking occurred, resulting in higher efficiencies, which could be further increased by using thicker ITO films consisting of five layers, but were still lower compared to nanoporous ZnO films electrodeposited on flat ITO. The major factors that currently limit the application are the still low thickness of the mesoporous ITO films, too small pore sizes and non-ideal geometries that do not allow obtaining full coverage of the ITO surface with ZnO before pore blocking occurs.

A new manufacturing paradigm may lower the cost and environmental impact of existing products, as well as enable completely new products. Large scale, roll-to-roll manufacturing of flexible electronics and other functionality has great potential. However, a commercial breakthrough depends on a lower consumption of materials and energy compared with competing alternatives, and that sufficiently high performance and reliability of the products can be maintained. The substrate constitutes a large part of the product, and therefore its cost and environmental sustainability are important. Electrically conducting thin films are required in many functional devices and applications. In demanding applications, metal films offer the highest conductivity. In this thesis, paper substrates of various type and construction were characterized, and the characteristics were related to the performance of inkjet-printed metal patterns. Fast absorption of the ink carrier was beneficial for well-defined pattern geometry, as well as high conductivity. Surface roughness with topography variations of sufficiently large amplitude and frequency, was detrimental to the pattern definition and conductivity. Porosity was another important factor, where the characteristic pore size was much more important than the total pore volume. Apparent surface energy was important for non-absorbing substrates, but of limited importance for coatings with a high absorption rate. Applying thin polymer–based coatings on flexible non-porous films to provide a mechanism for ink solvent removal, improved the pattern definition significantly. Inkjet-printing of a ZnO-dispersion on uncoated paper provided a thin spot-coating, allowing conductivity of silver nanoparticle films. Conductive nanoparticle films could not form directly on the uncoated paper. The resulting performance of printed metal patterns was highly dependent on a well adapted sintering methodology. Several sintering methods were examined in this

A new manufacturing paradigm may lower the cost and environmental impact of existing products, as well as enable completely new products. Large scale, roll-to-roll manufacturing of flexible electronics and other functionality has great potential. However, a commercial breakthrough depends on a lower consumption of materials and energy compared with competing alternatives, and that sufficiently high performance and reliability of the products can be maintained. The substrate constitutes a large part of the product, and therefore its cost and environmental sustainability are important. Electrically conducting thin films are required in many functional devices and applications. In demanding applications, metal films offer the highest conductivity. In this thesis, paper substrates of various type and construction were characterized, and the characteristics were related to the performance of inkjet-printed metal patterns. Fast absorption of the ink carrier was beneficial for well-defined pattern geometry, as well as high conductivity. Surface roughness with topography variations of sufficiently large amplitude and frequency, was detrimental to the pattern definition and conductivity. Porosity was another important factor, where the characteristic pore size was much more important than the total pore volume. Apparent surface energy was important for non-absorbing substrates, but of limited importance for coatings with a high absorption rate. Applying thin polymer–based coatings on flexible non-porous films to provide a mechanism for ink solvent removal, improved the pattern definition significantly. Inkjet-printing of a ZnO-dispersion on uncoated paper provided a thin spot-coating, allowing conductivity of silver nanoparticle films. Conductive nanoparticle films could not form directly on the uncoated paper. The resulting performance of printed metal patterns was highly dependent on a well adapted sintering methodology. Several sintering methods were examined in this

A new manufacturing paradigm may lower the cost and environmental impact of existing products, as well as enable completely new products. Large scale, roll-to-roll manufacturing of flexible electronics and other functionality has great potential. However, a commercial breakthrough depends on a lower consumption of materials and energy compared with competing alternatives, and that sufficiently high performance and reliability of the products can be maintained. The substrate constitutes a large part of the product, and therefore its cost and environmental sustainability are important. Electrically conducting thin films are required in many functional devices and applications. In demanding applications, metal films offer the highest conductivity. In this thesis, paper substrates of various type and construction were characterized, and the characteristics were related to the performance of inkjet-printed metal patterns. Fast absorption of the ink carrier was beneficial for well-defined pattern geometry, as well as high conductivity. Surface roughness with topography variations of sufficiently large amplitude and frequency, was detrimental to the pattern definition and conductivity. Porosity was another important factor, where the characteristic pore size was much more important than the total pore volume. Apparent surface energy was important for non-absorbing substrates, but of limited importance for coatings with a high absorption rate. Applying thin polymer–based coatings on flexible non-porous films to provide a mechanism for ink solvent removal, improved the pattern definition significantly. Inkjet-printing of a ZnO-dispersion on uncoated paper provided a thin spot-coating, allowing conductivity of silver nanoparticle films. Conductive nanoparticle films could not form directly on the uncoated paper. The resulting performance of printed metal patterns was highly dependent on a well adapted sintering methodology. Several sintering methods were examined in this

Graphene oxide is a chemically modified form of graphene. With its ease of synthesis, functionalization, reduction and processing possibilities it emerges as a highly versatile nano-building block for the development of functional graphene-like materials of use for real-world applications. The importance of effective synthesis strategies and processing routes to profit at maximum from graphene oxide's surprising properties up to the proof of concept in different types of applications will be described by several examples of our ongoing research: 1.) The first examples refers to the processing of graphene oxide into conductive films and paper-like materials and its use as capacitative transducer material or direct electrode for improved potentiometric sensing of ions, living microorganisms and organic analytes [1-4]. 2.) The second example describes the combination of graphene oxide with intrinsically conducting polymers. With its unique ability to simultaneously act as electron acceptor and giant counter-ion it allows the formation of a stable solid-state charge-transfer complex stable and redispersible (processible) in aqueous dispersions [5] 3.) The last example focuses on the preparation of palladium nanoparticles (Pd-NPs) firmly supported on reduced graphene oxide (RGO) and the use of the corresponding Pd-NP/RGO hybrid material as efficient catalyst for hydrogenation reactions. Remaining oxygen functionalities play a critical role for the preparation as well as in the catalytic reactions [6]

Printing of functional materials requires reliable deposition processes. This work describes the development of printing processes for selected functional materials utilizing industrial-type inkjet printheads. A well-controlled printing process with fluids containing the conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is presented, allowing linear printing speeds of up to 0.35 m/s in single-pass, and smallest line width of approximately 40 μm when printing 7 pL drop volumes. In addition reliable processes for producing ZnO-based films, which enable novel applications for electronic and UV-sensitive devices, and for printing of conductive carbon nanotube layers are shown., QC 20140905

Aluminum doped ZnOx (ZnOx:Al) films have been deposited on glass in an in-line industrial-type reactor by a metalorganic chemical vapor deposition process at atmospheric pressure. Tertiary-butanol has been used as oxidant for diethylzinc and trimethylaluminium as dopant gas. ZnOx:Al films can be grown at very high deposition rates of ~14 nm/s for a substrate speed from 150 to 500 mm/min. The electrical, structural (crystallinity and morphology) and optical properties of the deposited films have been characterized by using Hall, four point probe, X-ray diffraction, atomic force microscope and spectrophotometer, respectively. All the films have c-axis, (002) preferential orientation and good crystalline quality. ZnO x:Al films are highly conductive (R<9 O/sq, for a film thickness above 1300 nm) and transparent in the visible range (>80%). These results show that ZnOx:Al films with good electrical and optical properties can be grown with a high throughput industrial CVD process at atmospheric pressure. First pin a-Si:H solar cells have been deposited on this material, with initial efficiency approaching 8%. © 2011 Elsevier B.V. All rights reserved.

High efficiency organic photovoltaic cells discussed in literature are normally restricted to devices fabricated on glass substrates. This is a consequence of the extreme brittleness and inflexibility of the commonly used transparent conductive oxide electrode, indium tin oxide (ITO). This shortcoming of ITO along with other concerns such as increasing scarcity of indium, migration of indium to organic layer, etc. makes it imperative to move away from ITO. Here we demonstrate a highly flexible Ag electrode that possesses low sheet resistances even in ultra-thin layers. It retains its conductivity under severe bending stresses where ITO fails completely. A P3HT:PCBM blend organic solar cell fabricated on this highly flexible electrode gives an efficiency of 2.3%.

Edited trans. of Prace Przemyslowego Instytutu Elektroniki (Poland) v18 n61 p5-21, 45-51 1977, by Carol S. Nack and Joseph E. Pearson.