Fig 3 - uploaded by Naji Al-Dahoudi
Content may be subject to copyright.
Source publication
Stable suspension made of fully redispersable In2O3:Sn (ITO) conducting nanoparticles were developed to obtain single thick transparent conducting films (up to 500nm) on different substrates using wet chemical deposition methods. The coatings can be processed at high sintering temperature process on glass substrates up to 1000°C to get electrical r...
Contexts in source publication
Context 1
... coating is used for many applications in different technological fields. Thin films can be obtained by depositing drops of the solution on the surface of a flat substrate and then spun it to leave a uniform layer for subsequent processing stages and ultimate use. The stages of forming thin films are described as the followings below (34) (Fig. ...
Context 2
... density of ITO particles calcined at T = 350 °C as a function of the Sn-doping concentration and that of particles doped with 8 at % Sn as a function of the calcination temperature are shown in Fig. 13. Pure indium oxide particles heat treated at 350°C are quite dense, ρ ~ 6.93 g/cm 3 , about 96.5 % of the theoretical value (7.18 g/cm 3 ) but their density decreases gradually with the increase of the Sn concentration down to 6.6 g/cm -3 (12 at. % Sn) (Fig. 13 a). This means that the tin doping leads to a lower packing within the ...
Context 3
... doped with 8 at % Sn as a function of the calcination temperature are shown in Fig. 13. Pure indium oxide particles heat treated at 350°C are quite dense, ρ ~ 6.93 g/cm 3 , about 96.5 % of the theoretical value (7.18 g/cm 3 ) but their density decreases gradually with the increase of the Sn concentration down to 6.6 g/cm -3 (12 at. % Sn) (Fig. 13 a). This means that the tin doping leads to a lower packing within the particles (larger ...
Context 4
... a given doping concentration, the ITO particles become denser as a function of the sintering temperature (Fig. 13 b). This means that the pores inside the particles are gradually removed and that the grains building the particles become more tightly packed. 14 shows that the specific surface area (BET) of the powders decreases gradually by increasing the calcination temperature from 64 m 2 /g at 250 °C down to 21 m 2 /g at 550 °C. This result is due ...
Context 5
... measurements were carried out in order to investigate the structural properties of pure ITO coatings made of redispersable indium tin oxide nanopowders. Fig. 30 shows typical XRD patterns made with the the ITO350 sol and spin coated on fused quartz substrates and then heat treated in air at 130, 550, and 1000°C. The layer heated at low temperature 130°C was deposited on borosilicate glass. As expected all the films are polycrystalline. They show the same cubic bixbyite In 2 O 3 phase crystal ...
Context 6
... surface morphology of the coatings sintered at different temperatures and post annealed in a reducing atmosphere is shown in Fig. 31. As expected, all films consist of nano- crystalline particles, which have approximately a regular granular shape. The growth of the particles with the sintering temperature is clearly observable. The grain size of the film sintered at 550°C ranges between 35-45 nm, that of films sintered at 750°C between 50-60 nm and that sintered at ...
Context 7
... electrical properties of indium tin oxide coatings were characterised as a function of the doping concentration (Fig. 32), the heat treatment (Fig. 34, Fig. 35) and the type of the coating sol (Fig. 32). As shown in Fig. 32, the specific resistivity of spin coated ITO layer sintered in air at T = 550 °C first decreases with increasing Sn concentration, passes by a minimum at around 6 to 8 mol % and then increases. The ITO layers made of ITO350 particles show a minimum of the resistivity at a ...
Context 8
... in the case of the particles sintered at lower temperature. In addition the ITO350 particles were found to have larger crystallite size than the ITO250 ones, so that the electron scattering at grain boundaries is smaller. The specific resistivity, carrier density and mobility of ITO350 layers as a function of the doping concentration is shown in Fig. 33. It is seen that the carrier mobility is low and continuously decreases with increasing Sn doping and, as expected, that the carrier concentration increases, passes by a maximum at 6 wt. % and then decreases. This shows that the decrease of the resistivity of the films with the Sn concentration is essentially due to the increase of the ...
Context 9
... scattering centers and do not donate free electrons. Omata et al (295) reported that the increase of Sn concentration in ITO layers results in an increase of the interstitial oxygen ions which behave as a trap of the mobile electrons. The effect of the sintering time on the specific resistivity was tested at 550 °C for spin coated ITO250 layers (Fig. 34). The specific resistivity first decreases, passes by a minimum value for a firing time of about 30 min and then slightly increases. This period of time is sufficient to sinter the particles and to bring them close together. The increase of the resistivity at longer time may be attributed to the oxidation of the film due to a slow ...
Context 10
... increase of the resistivity at longer time may be attributed to the oxidation of the film due to a slow oxygen surface chemisorption effect, which removes the oxygen vacancies and reduces the concentration of charge carriers. The sintering of the layers was also tested up to 1000 °C with films deposited by spin coating on fused quartz substrates. Fig. 35 shows the variation of the specific resistivity, ρ, and the sheet resistance, R , of single ITO350 layer fired in air at different temperatures during 30 min and also further post annealed in forming gas (N 2 /H 2 : 92/8) at 350°C during 30 min. The Sn concentration of the coatings was 7 mol%. The resistivity of the film fired in air ...
Context 11
... in air at 550°C is 4.8x10 -2 Ωcm and decreases gradually by increasing the firing temperature down to 1.2x10 -2 Ωcm at T = 1000°C. This behaviour is related to a better sintering and to the growth of the particles which improve remarkably the carrier mobility which varies from 1.08 cm 2 / V.s at 550 °C to 4.25 cm 2 / V.s at 1000 °C as shown in Fig. 36. Increasing the sintering temperature also leads to a slight increase of the carrier concentration from 1.19x10 20 cm -3 at 550 °C to 1.55x10 20 cm -3 at 1000 °C. These results are in agreement with the growth of the crystallite size calculated from the XRD pattern (section 5.4.1) which increases from 25 nm at 550°C to 33 nm at 1000°C ...
Context 12
... crystallite size calculated from the XRD pattern (section 5.4.1) which increases from 25 nm at 550°C to 33 nm at 1000°C and with the SEM observations of the surface morphology of the coatings where the growth of the particles and a denser structured layer with larger and sharper grain size is clearly observed by increasing the firing temperature (Fig. ...
Context 13
... treatment in non oxidizing atmosphere leads to a slight increase (typically 11 %) of the charge mobility but to a significant increase of the carrier concentration as shown in Fig. 37. The mobility and the carrier density for the film sintered at 550 °C in air are 1.08 cm 2 / V.s and 1.2x10 20 cm -3 , respectively (Fig. 36) and increases after post annealing to 1.2 cm 2 / V.s and 3.32x10 20 cm -3 respectively (Fig. 37). The carrier mobility and concentration increase gradually with the sintering temperature up to ...
Context 14
... treatment in non oxidizing atmosphere leads to a slight increase (typically 11 %) of the charge mobility but to a significant increase of the carrier concentration as shown in Fig. 37. The mobility and the carrier density for the film sintered at 550 °C in air are 1.08 cm 2 / V.s and 1.2x10 20 cm -3 , respectively (Fig. 36) and increases after post annealing to 1.2 cm 2 / V.s and 3.32x10 20 cm -3 respectively (Fig. 37). The carrier mobility and concentration increase gradually with the sintering temperature up to 5.32 cm 2 / V.s and 7.63x10 20 cm -3 at 1000 ...
Context 15
... (typically 11 %) of the charge mobility but to a significant increase of the carrier concentration as shown in Fig. 37. The mobility and the carrier density for the film sintered at 550 °C in air are 1.08 cm 2 / V.s and 1.2x10 20 cm -3 , respectively (Fig. 36) and increases after post annealing to 1.2 cm 2 / V.s and 3.32x10 20 cm -3 respectively (Fig. 37). The carrier mobility and concentration increase gradually with the sintering temperature up to 5.32 cm 2 / V.s and 7.63x10 20 cm -3 at 1000 ...
Context 16
... values shown in Fig. 35, 36 were measured at least one week after the production of the coatings and correspond to stable values. Interestingly it was observed that the specific resistivity and the sheet resistance of the post annealed coatings measured immediately after the process was lower and unfortunately increases with time until reaching a stable value. ...
Context 17
... Fig. 35, 36 were measured at least one week after the production of the coatings and correspond to stable values. Interestingly it was observed that the specific resistivity and the sheet resistance of the post annealed coatings measured immediately after the process was lower and unfortunately increases with time until reaching a stable value. Fig. 38 shows the sheet resistance of the ITO coatings measured at three different stages: before annealing, immediately after annealing and after storage in air during one week (20 °C, 40 % RH). The time evolution of the sheet resistance of the post annealed layers varies significantly and depends on the temperature at which the layer was ...
Context 18
... become more difficult and the specific surface area of the particles become smaller so that the surface chemisorption reactions are reduced. This explains the slighter changes of the sheet resistance of the samples fired at 1000°C comparing to that fired at lower temperatures. This also explain the small variation shown for the carrier density in Fig. 36, where smaller surface results in less interaction with the adsorbed oxygen ...
Context 19
... refractive index of the coatings was measured by the VASRA method (see appendix A3.3). Fig. 39 shows the B θ shifts to higher value when the firing temperature raises. The refractive index of the coating at λ = 550 nm increases from 1.52 to 1.62 when the firing temperature raises from 550 to 1000°C respectively. The measurements of the refractive index using the ellipsometry method shows the same trend. All the results are ...
Context 20
... information which corroborates the above discussion is the optical behaviour of the coatings sintered at different temperatures and further annealed in forming gas. Fig. 43 and Fig. 44 show some representative T and A curves for coatings sintered between 550 °C and 1000 °C. ...
Context 21
... the electrical resistivity strongly decreases with the increase of the sintering temperature (see Fig. 35), a shift of the near IR transmission edge toward lower wavelength was expected, but the contrary is observed. This behaviour is due to the shift of the large IR absorption edge toward longer wavelength (Fig. 44). Equation [41] and the variation of the ratio n /µ obtained from the dc electrical data (see Fig. 37) indicate that such a ...
Context 22
... of the sintering temperature (see Fig. 35), a shift of the near IR transmission edge toward lower wavelength was expected, but the contrary is observed. This behaviour is due to the shift of the large IR absorption edge toward longer wavelength (Fig. 44). Equation [41] and the variation of the ratio n /µ obtained from the dc electrical data (see Fig. 37) indicate that such a behaviour should be observed, but the values independent of the frequency can not explain the results. Similar observation was found by Bommel et al (70) for layers made of redispersable ATO particles, however no explanation for the shift toward longer wavelength was ...
Context 23
... shift of the optical band gap was observed although the resistivity of the coatings decreased by 3 order of magnitude. A similar behaviour has been observed for coatings sintered at the same temperature and then reduced in forming gas at 350 °C for 30 min, although in this case a much larger variation of n with the temperature has been observed (Fig. ...
Context 24
... is worth to remember that the temperature reached by the coated substrates also depends on the conveyor speed (see Fig.8). A heat treatment in a reducing atmosphere ( N 2 /H 2 : 92/8) at 130 °C has however a more drastic improvement on the sheet resistance of the layers which is decreased from about 8 kΩ down to 2 kΩ after a two hours treatment (Fig. 53). An increase of the time slightly degrades the sheet resistance by about 5 %. ...
Context 25
... cured MPTS/ITO layer shown in Fig To better investigate the structure of MPTS/ITO coatings on polymeric substrate, TEM spectroscopy was carried out. The preparation of thin cross sections using the conventional ion-milling technique is very difficult because of the ion damage of the polymeric substrates, thus ultramicrotomy was used instead. (Fig. 73 a) and a very loose packing ITO particles in the case of thermally cured sample (Fig. 73 b). ...
Context 26
... on polymeric substrate, TEM spectroscopy was carried out. The preparation of thin cross sections using the conventional ion-milling technique is very difficult because of the ion damage of the polymeric substrates, thus ultramicrotomy was used instead. (Fig. 73 a) and a very loose packing ITO particles in the case of thermally cured sample (Fig. 73 b). ...
Context 27
... solutions deposited on the surface and was modelled by several authors. The total surface energy σ s consists of two components, a polar part σ p resulting from the different intermolecular forces due to the permanent and induced dipoles and hydrogen bonding and a dispersion part σ d (nonpolar) due to the instantaneous dipole moment (327). Fig. 83 shows the time variation of the contact angle of water and the surface energy of MPTS/ITO film during the UV-treatment and determined using the model of Wu (340). The contact angle of water decreases considerably from 54 ° down to a minimum of 11.4 ° and the surface becomes hydrophilic. The total surface energy of the layer increases ...
Similar publications
- [...]
Traditional passive jamming materials such as chaff and foil showed some limitations in use because they can only reflect the electromagnetic wave. Therefore, to develop a kind of absorptive passive jamming material to make up for deficiencies of traditional passive jamming materials and improve the jamming efficiency is of great significance. In t...
Recently, doped CdS nanostructures has attracted attention not only because of their tunable optical and electrical properties [12] but also due to inherent potential for many technological applications such as wavelength controlled lasers [13] and solar cells [14]. Several CdS quantum dot(QD) embedded in PVA matrix were prepared in thin film form...
YBa2Cu3O7−δ (YBCO) films were deposited on (100)-oriented LaAlO3 (LAO) single crystal substrates by the dip-coating process using low-fluorine solution. Their microstructures were characterized with the aid of X-ray diffractometry, scanning electron microscopy and high-resolution transmission electron microscopy. Their superconducting properties we...
Flexible glass fiber-supported nitrogen-doped titanium dioxide (GF-N-TiO2) photocatalysts with different N/Ti ratio were prepared using a dip-coating method followed by a low-temperature heat-treatment process. In addition, their photocatalytic activities were evaluated for the degradation of aromatic volatile organic compounds (VOCs) under visible...
The aim of this work was to characterize the chemical changes during solid state solution heat treatment of a metallurgically bonded steel/Al-Si interface. For this purpose, low carbon steel plates covered with the A-S7G03 aluminium alloy (7 wt.% Si, 0.3 wt.% Mg analogous to A356) were prepared by dip coating, water-quenching to room temperature an...
Citations
... 26 Deposition using colloidal suspension of already crystalline nanoparticles is another interesting option, in which the crystallization step of the TCO material is separated from the process of film formation. 27 It is worth mentioning that synthesis of transparent conductive coating starting with low cost material like crystalline ZnO nanoparticles with simple steps will be a significant achievement for the industry to coat many kinds of substrates especially formed glasses and polymeric substrates. ...
Transparent conducting aluminum doped zinc oxide Al:ZnO (AZO) layers have been deposited by spin coating on glass substrates using two different sols, 1-propanolic solution of Zinc and Aluminum salts (conventional sol) and a suspension of already crystalline AZO nanoparticles redispersed
in 1-propanol. The coatings have been sintered in air at 600 °C for 15 min. and then post annealed in a reducing atmosphere at 400 °C for 90 min. The influence of the aluminum content in the coating sol (sol–gel layer) and in the redispersed nanoparticles (nanoparticulare suspension
layer) on the optical properties and electrical resistivity have been investigated. A single step spin coated thin layer is obtained, so that multilayers coating have been used to lower the obtained sheet resistance. The visible transmission of both types of layers is high (T > 80%).
The influence of the sintering temperature and the optimum doping concentration are investigated. Seven layers synthesized with Al/Zn = 1 mol.% and submitted to reducing treatment in forming gas (N2:H2 = 92:8) exhibited a sheet resistance R = 0.42 k (ρ = 7.9
× 10–3 Ω · cm) with an average transmittance of 80% at 550 nm for layer deposited from conventional sol and 36 k (ρ = 2.5 × 10–1 Ω · cm) for nanoparticles suspension layer.
... Coatings have been prepared with sols containing small amount of polymerizable prehydrolyzed organosilanes. Among them, the use of MPTS led to the best electrical, optical, structural and mechanical properties [4]. ...
... The influence of the carriers is clearly seen by the strong absorption ( A = 1 -T -R) occurring in the near IR range (900 < < 3 µm) and the increase of the reflection starting at 1.7 µm extending to R 45% at = 20 µm. Similar results have been obtained for coatings deposited on different plastic material such as PVC, PMMA, PET (thick and foil substrates) [4]. The strong decrease of T in the UV range ( < 400 nm, ITO band-band transition) protects the plastic substrates against UV radiation while that due to the carrier ( > 900 nm) offers a sun and heat radiation protection. ...
... Antiglare-antistatic obtained by a spraying process to get a final surface morphology with micrometer size roughness are reported in [3,4]. ...
Introduction Experimental Coating Sintered at High Temperature Coating Polymerized at Low Temperature Conclusion
... Al-Daoudi could improve the adhesion of his powder-derived ITO layers by using TEOS, GPTS and MPTS coupling agents [121]. Silanes are very effective at improving adhesion between two otherwise incompatible materials. ...
... Thermal analysis are methods by which the physical and chemical properties of a substance, a mixture and/or reaction mixtures are analyzed as a function of temperature or time, while the sample is subjected to a controlled temperature program. The program may involve heating or cooling (dynamic), or holding the temperature constant (isothermal), or may combination of these [34]. ...
Electrochromic (EC) materials change their optical properties (transmittance or reflection) in a reversible manner when a current flows through them. Large EC glazings can be used for architectural and automotive applications in order to control the solar radiation entrance. The typical configuration of EC devices made with the sol-gel process (and used in our lab) is glass/fluorine doped tin oxide (FTO)/EC layer/inorganic-organic composite electrolyte/ion-storage (IS) layer/FTO/glass. The ion storage capacity of the IS layer plays an important role in the transmittance change of EC devices. WO3 layers are the best studied EC layers and their Li+ intercalation ability is larger than 30 mC/cm². The charge capacity of the IS layer should be similar to obtain a high coloration change. My work was dedicated to improve the ion storage capacity of (CeO2)x(TiO2)1 as IS layer. First the composition of the sol and the dip coating and annealing parameters have been optimized. Then the influence of water added to the electrolyte on the properties of the EC and IS layers and the EC devices has been studied. The ion storage capacity was improved from 7 mC/cm² to 14.5mC/cm² by improving the sintering temperature to 550°C. It can be even increased to 26mC/cm² by increasing the thickness of the layer and with 3 wt.% water added into the liquid electrolyte. When a small amount of water is added to the liquid electrolyte, 1 M LiClO4 in propylene carbonate (PC), the ion storage capacity of the (CeO2)x(TiO2)1 layer is greatly increased by a factor up to 3 and the ion intercalation kinetics is faster than that in the dry electrolyte. The ion intercalation reversibility is also improved. The nature of the intercalated ion was studied using an Electrochemical Quartz Crystal Microbalance (EQCM). It was foun that the charge balance of the (CeO2)0.81(TiO2)1 layer during reduction and oxidation is not only due to Li+ intercalation and deintercalation, but also to ClO4 desorption and adsorption. [...]
Numerous studies on Cu-doped ZnO (CZO) thin film doped as a p-type material have been reported due to its applications in optoelectronic and gas sensing devices. The synthesis and fabrication of CZO thin films by various techniques have been reported, but the sol-gel technique for both spin and dip coating has attracted much attention due to its safety, low cost and simple deposition equipment on a large surface-area. Motivated by the fact that reviews on CZO thin films have not been reported yet, this review summarizes the main chemical processes used in the fabrication of CZO thin films with special focus on the sol-gel synthesis involving several chemical and physical parameters such as solvent, additive, solution stirring and aging time, substrate and coating method which includes both dip and spin coating. It also highlights the various parameters influencing the structural, morphological, electronic, optical, vibrational and magnetic properties of the CZO thin films. For this purpose, a summary of various parameters of CZO thin films, reported in the literature survey of the past ten years (2010-2020), is tabulated and discussed. The influence of Cu doping on the synthesis and properties of CZO thin films is also reviewed. The structural, electronic, optical, magnetic and vibrational properties, as well as the elemental composition and surface morphology of the CZO thin films are also discussed. At the end of this review, an outlook is presented to gain more insights into the combined effects of the method-preparation-dopant combination on the properties of CZO thin films for future potential applications. This review should be a useful benchmark for researchers to explore the various physicochemical properties of CZO, their dependence on the experimental conditions and applications.
The corundum structures of In2O3:Sn (ITO) nanoparticles were synthesized by hydrothermal processing of InCl3 and SnCl4·5H2O precursor at low temperature of 250 °C and 40bar pressure for 3 h. The precursor was precipitated in a white gel of InOOH.
After drying at 150 °C in air, it was crystallized in orthorhombic structure. InOOH powder was transformed into dark-gray
rhombohedral In2O3 by sintering at 420 °C in forming gas for 1h. The samples were characterized by means of XRD, SEM, and TEM. The particle
size of the resulted ITO powder was about 32nm.
KeywordsHydrothermal process-Corundum structure-ITO-Rhombohedral-Nanoparticles-Optic and electronic applications
