PVP a binder for the manufacture of ultrathin ITO/polymer nanocomposite films with improved electrical conductivity

Transparent conductive indium tin oxide (ITO) films with thin Ni-doped surface layers were prepared for organic light emitting diode (OLED) application. The top Ni-doped ITO surface layer were synthesized using Ni (RF) and ITO (DC) co-sputtering method at 120°C and annealed at 300°C for 10 minutes in vacuum to form a modulated work function layer in contact with the subsequently deposited light emitting organic layers. OLED devices with an Al/Alq3/NPB/Ni-doped ITO/ITO/glass structure were fabricated to investigate the effect of the Ni-doped ITO layer on the characteristics of the luminescence efficiency. The depositions of the Al/Alq3/NPB stacked films on top of the Ni-doped ITO/ITO/glass sample were conducted using thermal evaporation in a cluster tool without breaking the vacuum. Initial results show that the device turn-on voltage decreases from 10 volts to 6 volts and the luminescence efficiency was improved by 36% due to the existence of the Ni-doped ITO layer. It was also found that the optical transmittance of the ITO film decreased with the Ni concentration, resulting in external quantum efficiency deterioration by 3%. It was suspected that the presence of Ni (Φ~5.2eV compared to that of ITO ~4.2eV) on ITO surface decreases the heterojunction barrier height at the ITO/NPB interface, allowing more effective transportation of hole-carriers and hence an enhancement on the external quantum efficiency. However the optical impurity scattering of the Ni atoms in the ITO matrix caused the deterioration of the optical transparency and negative effect on the external quantum efficiency.

Adhesion enhancement of indium tin oxide (ITO) coated quartz optical fibers

Indium tin oxide (ITO) films deposited with single layers of monodispersive fluorine-doped tin oxide (FTO) nanoparticles of several nanometers in size were grown on glass substrates by intermittent spray pyrolysis deposition using conventional atomizers. These films have significantly higher ionization potentials than the bare ITO and FTO films grown using the same technique. The ITO films covered with FTO particles of 7nm in average size show an ionization potential of 5.01eV, as compared with ∼4.76 and ∼4.64eV in ITO and FTO films, respectively, which decreases as the FTO particle size increases. The ionization potentials are practically invariant against oxidation and reduction treatments, promising a wide application of the films to transparent conducting oxide electrodes in organic electroluminescent devices and light-emitting devices of high efficiencies.

Solution-based fabrication methods can greatly reduce the cost and broaden the applications of transparent conducting oxides films, such as indium tin oxide (ITO) films. In this paper, we report on ITO films fabricated by spin coating methods on glass substrates with two different ITO sources: (1) a commercial ITO nanopowder water dispersion and (2) a sol-gel ITO solution. A simple and fast air annealing process was used to treat as-coated ITO films on a controlled temperature hot plate. Thermogravimetric analysis and x-ray diffraction showed that highly crystalline ITO films were formed after the annealing steps. The final ITO films had a good combination of optical properties and electrical properties, especially for films made from five layers of sol-gel ITO (92.66% transmittance and 8.7 × 10−3 Ω cm resistivity). The surface morphology and conducting network on the ITO films were characterized by non-contact and current atomic force microscopy. It was found that conducting paths were only partially connected for the nanoparticle ITO dispersion films, whereas the sol-gel ITO films had a more uniformly distributed conducting network on the surface. We also used the sol-gel ITO films to fabricate a simple liquid crystal display (LCD) device to demonstrate the excellent properties of our films.

Purpose: In order to offer a better understanding of the root causes of the electrochemical corrosion failure of indium tin oxide (ITO), the degradation mechanism was investigated with specific attention to changes in chemical composition and the crystalline phase, and then correlated with electrical resistance and optical transparency of the ITO film.BRMethods: An electrochemical polarization test was carried out in 1M HCl solution. For the interrupted specimens after specific corrosion times, various analytical characterizations were performed including scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, electrical resistance, and optical transmittance.BRResults: The polarization curve was divided into four distinct stages based on the varying electrochemical behaviors and the resulting changes in morphology/phase evolution were investigated. ITO film was corroded by breaking of In-O bonds followed by reduction of In3+ and Sn2+ ions. The reaction terminated with the formation of In-Cl particles as byproducts of corrosion. Electrical conductivity decreased abruptly with the dissolution of ITO film, and 5–10% variation in optical transparency of the ITO film was also recorded in response to the electrochemical activity.BRConclusion: Based on the chemical composition and phase analysis for the interrupted specimens at specific stages, the electrochemical corrosion mechanism was proposed, and this material degradation mechanism was correlated with that of the electrical resistance and optical conductivity, respectively.

Low pressure and temperature deposition of transparent conductive indium tin oxide (ITO) films by the face target sputtering (FTS) process

Preparation of transparent conductive indium tin oxide thin films from nanocrystalline indium tin hydroxide by dip-coating method

A tri-band transparent conductive indium tin oxide (In2O3:Sn, ITO) film for the visible, near-infrared (NIR) and mid-infrared (MIR) was deposited on a sapphire substrate by radio frequency (RF) magnetron sputtering. Deposition parameters, including RF power, substrate temperature, and oxygen flow rate, were optimized to improve the optical property without reducing the conductivity of the film by maximizing the Hall mobility and minimizing the carrier concentration. Films deposited at optimized conditions exhibit a Hall mobility of ∼20 cm2 V-1 s-1, a carrier concentration of ∼4.99×1020 cm-3, and a sheet resistance of 61.2 Ω/sq. Average transmissions of these films are 81.40% in the 0.4-1.6 μm region and 60.81% in the 3.0-5.0 μm region. An index-matching stack of MgF2 was developed, improving the transmittance to 90.55% and 73.20% in the regions above, respectively. These results make ITO film a promising alternative material to conventional metal mesh for missile domes shielding electromagnetic waves.

We demonstrate a method for the preparation of fully solution processed inorganic solar cells from a spin and spray coating deposition of nanocrystal inks. For the photoactive absorber layer, colloidal CdTe and CdSe nanocrystals (3-5 nm) are synthesized using an inert hot injection technique and cleaned with precipitations to remove excess starting reagents. Similarly, gold nanocrystals (3-5 nm) are synthesized under ambient conditions and dissolved in organic solvents. In addition, precursor solutions for transparent conductive indium tin oxide (ITO) films are prepared from solutions of indium and tin salts paired with a reactive oxidizer. Layer-by-layer, these solutions are deposited onto a glass substrate following annealing (200-400 °C) to build the nanocrystal solar cell (glass/ITO/CdSe/CdTe/Au). Pre-annealing ligand exchange is required for CdSe and CdTe nanocrystals where films are dipped in NH4Cl:methanol to replace long-chain native ligands with small inorganic Cl(-) anions. NH4Cl(s) was found to act as a catalyst for the sintering reaction (as a non-toxic alternative to the conventional CdCl2(s) treatment) leading to grain growth (136±39 nm) during heating. The thickness and roughness of the prepared films are characterized with SEM and optical profilometry. FTIR is used to determine the degree of ligand exchange prior to sintering, and XRD is used to verify the crystallinity and phase of each material. UV/Vis spectra show high visible light transmission through the ITO layer and a red shift in the absorbance of the cadmium chalcogenide nanocrystals after thermal annealing. Current-voltage curves of completed devices are measured under simulated one sun illumination. Small differences in deposition techniques and reagents employed during ligand exchange have been shown to have a profound influence on the device properties. Here, we examine the effects of chemical (sintering and ligand exchange agents) and physical treatments (solution concentration, spray-pressure, annealing time and annealing temperature) on photovoltaic device performance.

Compared with conventional transparent conductive indium tin oxide (ITO) films, poly(3,4-ethylenedioxythiophene):poly (styrenesulfonic acid) (PEDOT:PSS) as a conductive polymer material has been diffusely applied in organic optoelectronic devices. However, its optoelectrical properties need to be further improved. Therefore, a simple and universal approach with introducing ITO nanoparticles (NPs) was proposed to improve the optoelectrical properties of PEDOT:PSS thin films. The results show that the vertical conductivity (σDC⊥) and average transmittance (from 300 to 1200 nm) of PEDOT:PSS films were enhanced about 26.8 and 6.3%, respectively. Crystalline silicon (c-Si)/organic heterojunction solar cells (HSCs) with PEDOT:PSS/ITO NP hybrid films were fabricated and performances led to further improvement. The spatial distributions of relative electrical field intensity and the carrier generation rate of the HSCs under the standard AM 1.5 G condition were simulated, which were in good agreement with the experimental conclusions.

The large-sized naked-eye three-dimensional (3D) display is a critical device in the real-time topographic survey for deep-sea scientific research. As a core component, the low-impedance transparent conductive indium tin oxide (ITO) thin-film electrode lacks a reliable industrial preparation method. In the 3D display, the grating element with a low-resistance ITO film electrode should have a good binocular parallax to drive the display favorably. However, an increase in the ITO film temperature during deposition may induce its crystallization, and its etching residue may cause a short circuit between the ITO electrodes and abnormal display operation. In this work, we propose a simple and straightforward technique to produce amorphous thin ITO films by controlling the water vapor flow rate during the deposition process. The obtained ITO amorphous thick film (300 nm) can be etched without leaving residues on the display surface, ensuring vivid display performance of the 3D display. A field test employing the 3D display, consisting of a 3D parallax barrier and a two-dimensional (2D) display, does not exhibit a short-circuit phenomenon caused by residues encountered in previous devices. This work makes the 3D display applicable for the real-time topographic survey on the basis of both satisfying the nonetching residue and the decrease of the resistance value.

Transparent Conducting Indium Tin Oxide (ITO) and Zinc Oxide (ZnO) thin films were deposited with Pulsed Laser Deposition PLD at 300°C. The ITO films have small grain size of 5-10 nm and a high value transmission (95%) in the wavelength range from 300 to 700 nm with a low resistivity of 2.25 × 10 Ω.cm. While Zinc Oxide (ZnO) films have grain size of 15 nm and a transmission of 85% with a resistivity of 2.10 × 10 Ω.cm. A lower resistivity and better spectra selectivity is a measurement of the quality and potential use of transparent ITO and ZnO films for the application as anode electrodes for optoelectronic devices. The optimized ITO film was then used individually as anode in a solar cell based on organic conjugated polymer BEH-co-MEH-PPV. The cell fabricated in this study with an active layer made by solution-processed polymer. It was also found that the surface roughness and work function of oxide films are very important to enhance the stability and efficiency of electrode thin films used for solar cells. The solar cell structure ITO/BEHP-co-MEH-PPV/Al has shown a photovoltaic performance with open circuit voltages (Voc) of the cell being 0.45 V and power conversion efficiency of 6.4% and a fill factor of 40%. Original Research Article Article British Journal of Applied Science & Technology, 4(5): 739-748, 2014 740

Fabrication and structure characterization of ITO transparent conducting film by sol-gel technique

Preparation and properties of transparent conducting indium tin oxide films deposited by reactive evaporation

Tin-doped indium oxide (ITO) films with Sn/In atomic ratios in the range 0−0.1 were synthesized by electrochemically assisted deposition (EAD). The process involves a fast one-step cathodic deposition of a highly crystalline In−Sn hydroxide (InSnOH) film followed by thermal conversion into ITO at 300 °C. The cathodic precipitation of InSnOH is preceded by formation of an In−Sn complex in solution. The films were characterized by field emission scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, UV−visible spectroscopy, and electrical measurements. In the Sn/In atomic ratio range 0−0.1, InSnOH and ITO films adopt the morphologies and cubic crystal structures of In(OH)3 and In2O3, respectively. The atomic environment of Sn and O atoms in the ITO films was shown to resemble that of films deposited by other techniques and commercial ITO samples made by chemical vapor deposition. Separate tin oxide/hydroxide phases were not observed by any of the characterization methods. The mor...