Yang Ren

Optical and Electrical Properties of Large Area SnO2: F Thin Films by Spray Pyrolysis

SnO2:F transparent conductive thin films with the area of 500×500mm2 were deposited on glass substrates by spray pyrolysis using SnCl4•5H2O and HF as the starting material and dopant respectively in methanol. The effects of HF concentration on the crystallized status, microstructures, transmittance, conductivity and low emissivity performances of the films have been studied. The results indicated that when HF content was excessive the solution presented strong acidity and it was difficult to obtain the uniform and dense films. However, when HF content was less, the conductivity of the film was poor. In this paper, The optimal mount of dopant HF was investigated and the molar ratio of Sn to F is 1:0.5. And also the uniform and dense SnO2:F transparent conductive oxide thin films can be obtained, whose resistivity reached 6.36×10-4Ω•cm, and the average transmittance in visible region was 80%.The low emissivity of this film was 0.25, which could be used as the Low-E glass.

Preparation of Fluorine Doped Tin Oxide Film by Ultrasonic Spray Pyrolysis

Fluorine doped tin oxide (FTO) film is one of the most promising transparent conducting materials. It can be used for Low-E glasses, thin film solar cells, displays, etc. FTO film can be fabricated by various techniques. The technique of sol-gel combined with ultrasonic spray pyrolysis gives the possibility to produce high-quality large-scale FTO films. In this paper, the FTO sol is successfully prepared using pentahydrate stannic chloride (SnCl4•5H2O), hydrogen fluoride (HF) and methanol. Using the FTO sol, FTO films are prepared by ultrasonic spray pyrolysis technique. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM) are used to characterize the FTO films coated on glass substrates. Results indicate that the as-deposited films are polycrystalline SnO2 phase with tetragonal crystal structure, and that the average grain size for the samples is 160nm. The optical and electrical properties of the FTO film are also analyzed.

Preparation of ITO films using a spray pyrolysis solution containing an acetylacetone chelating agent

Indium tin oxide (ITO) films were deposited on soda-lime glass substrates by the spray pyrolysis method using a spray solution of InCl3·3H2O as a precursor, SnCl4·5H2O as a dopant and acetylacetone (AcAcH) as a chelating agent. The effect of the addition of AcAcH to the spray solution on the surface morphology of the ITO film was investigated. The surface quality of the film prepared from the spray solution with AcAcH was better than that without AcAcH. The ITO film with the thickness of 230 nm, using the spray solution with AcAcH, exhibited the lowest resistivity of 4.75 × 10−4 Ω·cm and higher optical transmittance of 85 %, respectively.

Preparation of a porous NiO array-patterned film and its enhanced electrochromic performance

In this paper, a novel photochemical etching technology, a photosensitive sol–gel method, was employed to prepare a porous NiO electrochromic patterned film. The sol was first prepared using nickel(II) acetate as the raw material, anhydrous methanol as the solvent and acetylacetone as the photosensitizer. Then, the chemically-modified NiO gel film was prepared on a glass substrate coated with ITO film. The obtained NiO gel film has a strong photosensitivity to ultraviolet light with a wavelength of 305 nm. Therefore, after UV exposure, rinsing with solvent and heat treatment, the NiO gel film covered with a porous array mask can be converted into a porous NiO array-patterned film. Compared to the compact NiO film, the porous NiO patterned film has a wider optical modulation range (51%), higher coloration efficiency (40 cm2 C−1), longer service life (with a peak current density reduction of <10% after 3000 cycles) and higher switching speed (coloring time 7 s, bleaching time 5 s).

Combined redox and plasmonic electrochromic effects in WO 3 /ITO double-layer films

AbstractIn this paper, a double-layer coating with both redox and plasmonic electrochromic properties has been designed and deposited on fluorine doped tin oxide (FTO) substrates by sol-gel method. This coating consists of an amorphous WO3 film and a nanocrystalline indium tin oxide (ITO) film. Both the valence of W atoms in WO3 and the localized surface plasmon resonance (LSPR) frequency of ITO nanocrystals can be tuned reversibly and persistently by electrochemical process. Due to the LSPR electrochromism, the double-layer films can block near-infrared (NIR) and visible (Vis) light selectively and independently by applying different voltages, which is better and more functional than the traditional electrochromic films. High transmittance of WO3/ITO films is obtained both in Vis and NIR for positive applied voltages. When a weakly negative voltage is applied, the transmittance of WO3/ITO films in visible region is still high, while the transmittance in NIR decreases. The transmittance of the double-layer films in both Vis and NIR further decreases for increasingly more negative voltages.

Preparation of photosensitive sol and patterned tungsten oxide films by using 2,2-dipyridyl as a chemical modifier

A tungsten oxide gel film was prepared from a methanol solution containing W-chelate, which was synthesized by the chemical reaction between WCl6 and 2,2-dipyridyl. The UV spectra results indicated that the gel film had a UV photosensitive behavior. Using its property, a tungsten oxide gel pattern was fabricated by selective irradiation followed by leaching in organic solvents. Finally, an amorphous WO3 pattern was obtained after the heat treatment at 250 °C in O2 ambient for 120 min. The optical contrast (ΔT) at a wave band of 632.8 nm was about 43%.Graphical Abstract

Fabrication of Textured Rough SnO2:F Films on Glass Using TiO2 Film as a Buffer Layer

This study proposes an alternative method for preparing SnO2:F films with a pyramid-like surface morphology that are suitable for the transparent electrodes used in amorphous silicon thin-film solar cells. By introducing a TiO2 film as a buffer layer, the crystallographic orientation of the SnO2:F films was changed from random to a (200) plane, and the surface topography of the SnO2:F film transformed from rod-like to pyramid-like; hence, textured, rough SnO2:F films were obtained. An appropriately textured rough surface improves light-trapping and enhances the photocurrent in amorphous silicon thin-film solar cells. The textured SnO2:F films were used as the front electrode in a 1-cm2 single-junction amorphous silicon solar cell yielding an initial efficiency of 9.3%. Light-trapping in the textured SnO2:F films led to a photo-generated current higher than that generated in smooth films.