Comparative study of transparent conductive In2O3:Sn (ITO) coatings made using a sol and a nanoparticle suspension

Transparent conducting In2O3:Sn (ITO) layers have been deposited by spin coating on glass substrates using two different solutions, an ethylene glycol solution of indium and tin salts (sol) and a suspension of crystalline ITO nanoparticles redispersed in ethanol. the coatings have been sintered in air at 550°C for 30 min. and then post annealed in a reducing atmosphere at 300°C for 30 min. The electrical, optical, morphological and mechanical properties of both types of coatings are compared. The use of the suspension leads to thick 500 nm single layers with a specific resistivity p=1.6 x 10(-2) Omegacm but only very thin ones, about 12 nm for a single layer, with p=1.8 x 10(-3) Omegacm (a factor 10 smaller) are obtained using the sol. The resisitivity still decreases down to a minium p=6 x 10(-4) Omegacm for multilayer coatings, a value quite close to that obtained by PVD or CVD processes. These differences originate from the different morphologies of the coatings. The conventional sol-gel layers exhibit a columnar structure with a low porosity (28%) while the others have a granular structure with a high porosity (51%). Corresponding the electron mobility µ is 14 and 1.1 cm²/Vs, respectively. The visible transmission of both types of layers is high (T>85%). The influence of the sintering temperature is also discussed

Wet chemical deposition of transparent conducting coatings made of redispersable crystalline ITO nanoparticles on glass and polymeric substrates

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 resistivity as low as 1.7x10(-3)Omega.cm and transmit more than 87% of the visible spectrum. The processing of transparent conductive coatings on polymeric (PC, PMMA, PVY, PE, PET, foils etc.) and glass substrates at low processing temperature was realized by using a modified ITO suspension in which a polymerisable inorganic-organic binder was added. The coatings can be cured by UV-irradiation and / Or by a low temperature heat treatment (T < 130°C) in air or reducing atmosphere. The electrical, optical, textural, mechanical and surface properties of the coatings are reported. Transparent conducting coatings with a single 570 nm thick layer exhibiting stable electrical resistivity of 9.2x10(-2) Omega.cm have been made by spin and dip coating process. A high transmission of about 87% is observed in the visible range. The adhesion and the abrasion resistance of the coatings pass the DIN or ASTMD tests: DIN58196-K2, ASTMD 3359, DIN 53151-Gt0, DIN 58196-G10 and DIN 58196-H25 and the hardness measured using the Pencil test ASTM D 3363-92a is 1H. UV-irradiation through a mask allows th easily pattern the coatings

-

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 resistivity as low as 1.7x10(-3)Omega.cm and transmit more than 87% of the visible spectrum. The processing of transparent conductive coatings on polymeric (PC, PMMA, PVY, PE, PET, foils etc.) and glass substrates at low processing temperature was realized by using a modified ITO suspension in which a polymerisable inorganic-organic binder was added. The coatings can be cured by UV-irradiation and / Or by a low temperature heat treatment (T < 130°C) in air or reducing atmosphere. The electrical, optical, textural, mechanical and surface properties of the coatings are reported. Transparent conducting coatings with a single 570 nm thick layer exhibiting stable electrical resistivity of 9.2x10(-2) Omega.cm have been made by spin and dip coating process. A high transmission of about 87% is observed in the visible range. The adhesion and the abrasion resistance of the coatings pass the DIN or ASTMD tests: DIN58196-K2, ASTMD 3359, DIN 53151-Gt0, DIN 58196-G10 and DIN 58196-H25 and the hardness measured using the Pencil test ASTM D 3363-92a is 1H. UV-irradiation through a mask allows th easily pattern the coatings

Wet-chemical processing of transparent and antiglare conducting ITO coating on plastic substrates

The paper reviews a low temperature sol-gel processing of transparent and antiglare conducting Sn doped indium oxide (ITO) coatings. The approach uses already crystalline nanoparticles which can be fully redispersed in an ethanolic sol containing a polymerisable organic binder. Thick single layers up to 600 nm can be deposited by spin and dip coating techniques followed either by a low temperature (<130°C) heat treatment or by a UV light irradiation. Stable resistivity down to 9.

Wet coating deposition of ITO coatings on plastic substrates

In2O3:Sn (ITO) transparent conducting coatings of high optical quality have been obtained on glass and several plastic substrates by spin and dip coating processes followed by a low temperature processing (T < 130°C). The sols are made of crystalline nanoparticles redispersable in an alcohol and modified by adding a binder to favour the coalescing of the particles and to allow the deposition of thick single layers (>400 nm). The smallest stable resistivity so far obtained is &rho; =

Alumina and Hafnia ALD Layers for a Niobium-Doped Titanium Oxide Photoanode

Niobium-doped titanium dioxide (TiO2) nanoparticles were used as a photoanode in dye-sensitized solar cells (DSCs). They showed a high photocurrent density due to their higher conductivity; however, a low open-circuit voltage was exhibited due to the back-reaction of photogenerated electrons. Atomic layer deposition is a useful technique to form a conformal ultrathin layer of Al2O3 and HfO, which act as an energy barrier to suppress the back electrons from reaching the redox medium. This resulted in an increase of the open-circuit voltage and therefore led to higher performance. HfO showed an improvement of the light-to-current conversion efficiency by 74%, higher than the 21% enhancement obtained by utilizing Al2O3 layers

Comparative study of transparent conductive In2O3:Sn (ITO) coatings made using a sol and a nanoparticle suspension

Transparent conducting In2O3:Sn (ITO) layers have been deposited by spin coating on glass substrates using two different solutions, an ethylene glycol solution of indium and tin salts (sol) and a suspension of crystalline ITO nanoparticles redispersed in ethanol. the coatings have been sintered in air at 550°C for 30 min. and then post annealed in a reducing atmosphere at 300°C for 30 min. The electrical, optical, morphological and mechanical properties of both types of coatings are compared. The use of the suspension leads to thick 500 nm single layers with a specific resistivity p=1.6 x 10(-2) Omegacm but only very thin ones, about 12 nm for a single layer, with p=1.8 x 10(-3) Omegacm (a factor 10 smaller) are obtained using the sol. The resisitivity still decreases down to a minium p=6 x 10(-4) Omegacm for multilayer coatings, a value quite close to that obtained by PVD or CVD processes. These differences originate from the different morphologies of the coatings. The conventional sol-gel layers exhibit a columnar structure with a low porosity (28%) while the others have a granular structure with a high porosity (51%). Corresponding the electron mobility µ is 14 and 1.1 cm²/Vs, respectively. The visible transmission of both types of layers is high (T>85%). The influence of the sintering temperature is also discussed

Synthesis and characterization of aluminum doped zinc oxide nanostructures via hydrothermal route

Stable crystalline aluminum doped zinc oxide (AZO) nanopowders were synthesized using hydrothermal treatment processing. Three different aluminum precursors have been used. The Al-precursors were found to affect the morphology of the obtained nanopowders. AZO nanoparticles based on zinc acetate and aluminum nitrate have been prepared with different Al/Zn molar ratios. XRD investigations revealed that all the obtained powders have single phase zincite structure with purity of about 99%. The effect of aluminum doping ratio in AZO nanoparticles (based on Al-nitrate precursor) on structure, phase composition, and particle size has been investigated. The incorporation of Al in ZnO was confirmed by UV-Vis spectroscopy revealing a blue shift due to Burstein-Moss effect

Wet chemical deposition of crystalline, redispersable ATO and ITO nanoparticles

A new wet chemical concept to produce coatings by dip, spin or spray processes is presented. It is based on the preparation of solutions made of crystalline nanoparticles fully redispersable in a solvent. It is exemplified for the preparation of SnO2 : Sb (ATO) and In2O3 : Sn (ITO) transparent conducting coatings. The process combines the advantages of using particles having already a low resistivity and the possibility to sinter the coatings at low temperature. The particles are prepared using an in-situ monitoring of the surface energy to control the growth of the particles and to avoid their agglomeration. The dried powders can be fully redispersed in alcohol (ITO) or water (ATO). Single layers with thickness up to 200 nm (ATO) and 400 nm (ITO) have been fabricated. The sheet resistance of the coatings decreases with the sintering temperature. Typical values are 430 &Omega;(open square) for ATO (550°C) and 380 &Omega;(open square) for ITO (550°C). Sols made by redispersing the powders in organosilanes allow to produce coatings at low temperature with antistatic (R(open square) > 100 k&Omega;(open square)) and anti-glare properties (R(open square) > 100 k&Omega;(open square), 60 to 80 gloss units)

Nanoplasmonic for Solar Energy Conversion Devices

The effect of nanoplasmonic (Ag) on the performance of DSSCs has been studied in doped and undoped ZnO (DZ and UZ) NPs, which were prepared by the urea-assisted combustion route. Different techniques were conducted to characterize DZ and UZ NPs. XRD patterns were indexed to the hexagonal wurtzite structure of ZnO NPs (ICSD-52362). The values of average crystalline size of UZ and DZ (1.0 mol% Ag) NPs were 20.45 and 22.30 nm, respectively. HR-TEM micrograph revealed good crystallization with an intermediate or poor agglomeration with distribution of semispherical morphologies of ZnO NPs. The energy bandgap of UZ and DZ NPs was changed from 3.21 to 3.31 eV. The deconvolution of the PL spectra recognized eight peaks into near ultraviolet (NUV) and visible regions. The PL emission of visible region overshadowed NUV transition. The photovoltaic cell with the doped photoanode DZ:1.0 mol% Ag exhibited the best performance parameters: Voc = 0.46 V, Jsc = 7.81 mA.cm−2, Pm = 1.91, FF = 51%, and η = 1.91%. A double exponential function was used as a powerful fitting function for the TOCVD data. The results revealed that τn in the UZ NPs photoanode was longer than that in the DZ:1.0 mol% Ag NPs photoanode