Papers by Keyword: Transparent Conducting Films

Abstract: This study dealt with the synthesis and characterization of thin transparent conducting films (TCF) from cellulose acetate (CA) blend and polyaniline (PANI). CA was produced from the pulp of abaca hybrid 7. CA-PANI films with different PANI loadings (0, 0.125, 0.25, 0.50, 1.0 and 2.0%) were produced using solvent casting method. Chemical transformations were analyzed using Fourier Transform Infrared (FTIR) spectroscopy. The conductivity was measured using the Four-Point Probe Test. Morphological characterization was done using Scanning Electron Microscopy (SEM). The transparency of the films was determined using UV-Vis Spectroscopy. FTIR spectra proved the embedment of PANI in the CA matrix. It was found that increasing the PANI loading increases the conductivity of the films but up to a certain limit. The highest average conductivity at 2.0264 x 10^-5 S/m was observed in CA-PANI films with 0.50% PANI loading. SEM images revealed that conductivity is a function of PANI loading by forming networks. Further addition of PANI (1.0 and 2.0%) resulted to decreased conductivity due to agglomeration. Transparency, on the other hand, is negatively affected by PANI loading.

Abstract: High aspect ratio silver nanowires (AgNWs) with an average length of 40 μm and average diameter of 88 nm were successfully synthesized using waste ethylene glycol as solvent and reducing agent. Silver nanowires with an average length and diameter of 32 μm and 122 nm, were produced after the third cycle of being reused. A transparent conducting film with a sheet resistance of 69 Ω/sq and optical transmittance of 91% was fabricated by Meyer rod coating an ink formulation of AgNWs dispersed in hydroxyethyl celullose (HEC)/methanol/deionized water. The low resistance of the AgNW networks was maintained even after 1000 bending cycles due to HEC acting as binder for the nanowires. The AgNWHEC transparent conductive electrode performed better than bare AgNWs and indium tin oxide (ITO) on polyethylene terephthalate (PET) substrate after several bending cycles. The AgNW-HEC electrode also showed excellent stability against corrosion.

Abstract: The use of graphene-based transparent conductive electrodes critically depends upon the enhancement of electrical conductivity with a negligible loss of optical transmittance of graphene. Hence, the hybridization of graphene and metal nanostructures has been intensively investigated to improve electrical conductivity. Here we demonstrate clusterization of PtCl2 on graphene by a facile method, MeV electron-beam irradiation (MEBI) under ambient conditions, as characterized by scanning electron microscopy, transmittance electron microscopy, and resonant Raman spectroscopy. The workfunction difference between PtCl2 nanoclusters and graphene results in p-type doping of graphene, to achieve a reduced sheet resistance of 69.1 % with respect to that of pristine graphene while maintaining transmittance of 91.7 %. The mechanism of formation of PtCl2 nanoclusters on graphene is likely to be defect-mediated clusterization due to the high energy electron-beam.

Abstract: Transparent conducting films of aluminum-, gallium or tin-doped and undoped zinc oxide were fabricated by dip coating process and post-deposition annealing in reducing gas atmosphere. Films were fabricated using zinc acetate and diethanolamine (stabilizer) with aluminum chloride hexahydrate, gallium chloride or tin (IV) chloride dissolved in ethanol. Dip coating and heating at 600°C in air were repeated ten times before annealing at 600°C in N₂-0.1%H₂. The average film thickness was 240 nm. The average visible transmittance exceeded 80%. Approximately 1 at.% of aluminum- or gallium-doping remarkably increased the carrier electron concentration and lowered the mobility. The lowest resistivity (6.57×10^-3 Ω∙cm) was achieved by doping of 0.8 at.%Al; the carrier electron concentration, the movility and the average visible transmittance were, 3.6×10¹⁹ cm^-3, 28 cm²∙V^-1∙s^-1 and 85%, respectively. Gallium-doping resulted in the lowest resistivity (8.09×10^-3 Ω∙cm) at 1 at.%Ga with the carrier concentration of 2.9×10¹⁹ cm^-3 and the mobility of 25 cm² V^-1 s^-1. Tin doping increased the resistivity. The resistivities, carrier electron concentrations and mobilities were compared with reported values deposited by other deposition process.

Abstract: Al-doped ZnO (ZnO:Al) thin films were deposited on glass substrates by rf magnetron sputtering technique. The effect of discharge power on the structural, optical and electrical characteristics of ZnO:Al films was investigated by X-ray diffraction (XRD), four-probe meter and optical transmission spectroscopy. The results show that the films are polycrystalline with a hexagonal wurtzite structure and preferentially oriented in the (002) crystallographic direction. The highest figure of merit of 5.58×10-3 -1 is obtained from the film prepared at the discharge power of 200 W. The average optical transmittance in the visible range of the films is over 78.2%.

Abstract: Transparent conducting Ti-Al co-doped zinc oxide films (TAZO) with high transparency and relatively low resistivity have been successfully prepared by direct current magnetron sputtering. The effect of sputtering power on the structural, optical, and electrical properties of Ti-Al co-doped films were investigated. The XRD patterns show that the thin films were highly textured along the c-axis and perpendicular to the surface of the substrate. The electrical resistivity decreases when the sputtering power increases from 40W to 120W. When the sputtering power is 120w and the target-substrate distance is 60mm, it is obtained that the lowest resistivity is 3.23×10^-4Ω·cm.The lowest stress is 0.864Gpa in all the deposited films. All the films present a high transmittance of above 91% in the visible range.

Abstract: Transparent conducting Ti-Al co-doped zinc oxide films (TGZO) with high transparency and relatively low resistivity have been successfully prepared on water-cooled glass substrate by DC magnetron sputtering at room temperature. All the deposited films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate. The Ar sputtering pressure was varied from 1.5 to 13 Pa. The electrical resistivity decreases when the sputtering pressure increases from 1.5 to 7.5 Pa. The electrical resistivity increases when the sputtering pressure increases from 7.5 to 13 Pa. When the sputtering pressure is 7.5 Pa, it is obtained that the lowest resistivity is 2.18×10-4Ω⋅cm. In the visible region, all the deposited films show a high average transmittance of above 92 %.

Abstract: Transparent conducting Ti-Ga co-doped zinc oxide (TGZO) thin films with high transmittance, low resistivity were firstly prepared on glass substrate by direct current (DC) magnetron sputtering at room temperature. X-ray diffraction (XRD) and scanning electron microscopy (SEM) show that the TGZO films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate. The lowest resistivity obtained in our experiment is 3.95×10-4Ω⋅cm. The average transmittance of the films is over 92% in the range of 400~760 nm.

Abstract: Ti-Ga co-doped ZnO thin films (TGZO) have been successfully prepared on glass substrates by DC magnetron sputtering at room temperature. The X-ray diffraction (XRD) patterns show that all the deposited films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate. The distance between target and substrate was varied from 41 to 75 mm. The crystallinity increases obviously and the electrical resistivity decreases when the distance between target and substrate decreases from 75 to 46 mm. However, as the distance decreases further, the electrical resistivity increases. It is obtained that the lowest resistivity is 2.0610-4cm when the distance between target and substrate is 46 mm. In the visible region, the TGZO films show a high average transmittance of above 90 %.

Abstract: Flexible transparent conducting (TC) film is a key element as the transparent electrode of the flexible electronics such as touch screen, solar cell, display or lighting. Current commercial flexible sputtered ITO films have shown some limitations; high sheet resistance (> 10 ohm/sq), deterioration of ITO film during repeatedly bending, indium scarce, and expensive fabrication process (sputtering). In this report, a new simple and cheap process to make such flexible TC film by using hot embossing and forming micro metal mesh underneath transparent conducting layer is proposed. This simple process has yielded a promising result with sheet resistance as low as 4 ohm/sq and the light transmission of 68% (@550nm). Future improvement on light transmission is discussed.