Sprayed CdS Films Research Articles

Photoelectrochemical properties of thin low cost polycrystalline CdS photoanodes

In the present paper photoelectrochemical processes and physical properties of the photovoltaic CdS|KClK 3 Fe(CN) 6K 4 Fe(CN) 6|Pt electrolytic cell have been studied. CdS polycrystalline photoanodes were prepared by pyrolytic spraying. The electrode resistance was measured and the film structure and composition were analyzed by SEM. Optical measurements were performed in order to determine the absorbance and the energy gap of the sprayed CdS films. Current-voltage characteristics as a function of the redox couple concentration and light intensity were measured under incandescent illumination and sunlight. Fill factors varied in the range from 0.2 to 0.4 and the efficiency of the yet non-optimized cells reached 0.4%. The problem of stability of the photoanode and its passivation were also discussed.

Optical and structural behaviour of Cu xS grown from copper, indium doped CdS sprayed thin films

Thin Cu x S layers are obtained by partial or complete dipping of doped sprayed CdS films. The CdS doping studies were made with the following impurities: copper, indium copper + indium, with different concentrations. The effects of the doping on the structural and optical properties of Cu x S layers are presented here. It is shown, that, unlike indium, copper above a few ppm induces degradation of almost all chemical and optical characteristics of the Cu x S layer by introducing serious damages on crystallinity of the CdS layer. By introducing indium with copper, the former tends to moderate this drastic effect and to bring the optical and structural properties of couple doped films to acceptable levels.

The optical properties of sprayed CdS thin films

In the study presented in this paper we attempted to interpret the reflectance and the transmittance of sprayed CdS films. Assuming a model based on multilayer film theory we showed that sprayed CdS film is a combination of multilayer stacks of crystallites and gaseous inclusions.

Structure and electronic properties of chemically sprayed CdS films

Abstract In this work we present a detailed study of chemically sprayed CdS thin films used in the fabrication of low cost solar cells. We investigated the physical properties of the films as well as their conditions of preparation. It was observed that the substrate temperature plays a very important role in determining the grain structure and the transport properties. Three types of film could be distinguished corresponding to three ranges of the deposition temperature. Significant differences existed in their film structure, deposition rate, conductivity, spectral response and photosensitivity. A somewhat high carrier density was observed for these films in comparison with those of previously studied CdS films and there was no obvious reason for this difference. Our improved photovoltaic cells were prepared on films deposited at temperatures below 300°C and this could be related to the structural variations.

A structural approach to the analysis of the electronic properties of chemically sprayed CdS films and cells

Presents a structural approach to the analysis of polycrystalline thin films and cells using physical lumped models. It was observed that although in theory the film mobility is proportional to the ratio of the grain to intergranular dimensions, this dependence was insufficient to explain the measured changes in mobility. Equivalent circuit models were also set up to consider the photovoltaic effects for three commonly observed film structures. Two limiting instances were identified corresponding to conditions of 'insulating grain boundaries' and 'leaky boundaries'. For the CuxS-CdS cells examined, the 'insulating grain boundaries' condition appeared more in line with experimental observations.

Use of centrifugal disk atomizer to produce CdS films

The use of a centrifugal disk atomizer to produce chemically sprayed CdS films is described. The film growth rate has been found to depend on substrate temperature, solution concentration, and feed rate. The films grown on glass substrates have been studied by electron microscopy and x-ray diffraction. A fine-grained wurtzite structure has been obtained.

CuxS/CdS thin-film solar cells using chemically sprayed CdS films

Presents the results of a study of the photovoltaic effect of CuxS/CdS thin-film solar cells formed on chemically sprayed CdS films using a dipping method. The investigation centres on the study of the effects of the properties of the chemically sprayed CdS films on the photovoltaic response of the resulting cells. This includes the study of the parameters of film deposition, film thickness, grain-size and structure, spectral response and I-V characteristics. In general, good photovoltaic cells can be made using the chemically sprayed films. The photovoltaic response in the cells has been limited by the series resistance losses as well as grain-size effect which is responsible for the lowering of the shunting resistance observed in cells made on relatively thicker films. The cell performance is believed to be dependent on the copper content and the distribution within the cell.