• Energy Research

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Abstract ZnO/CdS/CIS solar cell structures have been made by using different deposition techniques for each layer: standard rf-magnetron sputtering and chemical bath deposition for ZnO and CdS, respectively, and direct electrodeposition for CIS as a low-cost alternative to the co-evaporated absorber. Chemical studies of ZnO, CdS and CIS films, ZnO–CdS and CdS–CIS bilayers, and ZnO–CdS–CIS cells have been performed by utilising XPS. No chemical reactions were detected in the interfaces. Photovoltaic quality was evaluated from the spectral response data.

AbstractPolycrystalline CuIn1−xGaxSe2(CIGS) thin films were deposited by the non‐vacuum, near‐atmospheric‐pressure selenization of stacked metallic precursor layers. A study was carried out to investigate the influence of significant factors of the absorber on the solar cells performance. An efficiency enhancement was obtained for Cu/(In+Ga) atomic ratios between 0·93 and 0·95. The slope of the observed energy bandgap grading showed a strong influence on theVOCand the short circuit current densityJSC. An increase of the Ga content in the active region of the absorber was achieved by the introduction of a thin Ga layer on the Mo back contact. This led to an improvement of efficiency andVOC. Furthermore, an enhanced carrier collection was detected by quantum efficiency measurements when the absorber layer thickness was slightly decreased. Conversion efficiencies close to 10% have been obtained for these devices. Copyright © 2005 John Wiley & Sons, Ltd.

The influence of a thin metal underlayer on the chalcopyrite growth was studied. CuInSe2 (CIS) and CuIn1-xAlxSe2 (CIAS) thin films were grown by a two-stage process (stacked metal layers evaporation and subsequent selenization) onto Mo and bare soda-lime glass substrates. Due to the difficulty found for get CIAS samples onto Mo, a thin Al layer was evaporated before the metallic stack destined to obtain CIS and CIAS films. This work shows the differences that appear between the CIS and CIAS samples evaporated onto both substrates, with and without the thin Al underlayer. By means of the characterization of the samples, it has been observed that the use of Mo contact modifies the usual formation pathway of CIAS for the two-stage process. The evaporation of the thin Al layer on Mo promotes a higher grade of reaction of the CIAS phases.

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AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Abstract Transparent conducting oxides (TCOs) have a wide range of applications in several optoelectronic devices but beyond the conventional characteristics of transparency and conductivity different characteristics are required by each different technology. This constitutes a promising stimulation of the present research of TCO films. In order to investigate the possible application of antimony doped tin oxide (ATO) thin films as a TCO electrode for new concepts in solar cells and other optoelectronic devices, ATO thin films with adequate properties in terms of light transparency and conductivity were obtained using room temperature processes by oxygen-reactive DC magnetron sputtering, then the films were annealed in nitrogen atmosphere at a temperature of 350 °C. The effect of O 2 /(Ar+O 2 ) ratio in the sputter flow gas mixture has been studied. Results regarding to optical and electrical properties, microstructure and composition measurements are reported.

Abstract The influence of CdS thickness and TCO deposition condition on the optoelectronic, morphological and structural properties of CdSTCO bilayers has been studied. CdS was deposited by chemical bath, whereas the TCOs (ITO and aluminium-doped ZnO) were prepared by rf-magnetron sputtering. Cadmium sulphide thickness below 0.1 μm have been found to be optimal for avoiding optical absorption losses and conductivity deterioration. Though both types of window coatings, with TCO made at 25 and 200°C, have good quality, the ITO-based samples have shown a higher infrared transmission than those based on ZnO. Additionally, 10 and 70 minutes air-annealing treatments at 200°C have been carried out. Their analysis has demonstrated that the shorter ones are more suitable for enhancing structure maintaining unchanged electro-optical characteristics.

The morphology of CdS-indium tin oxide (ITO) and CdS-ZnO bilayers has been investigated by atomic force microscopy in order to obtain a better understanding of their behaviour as window coatings in solar cells. Chemical bath-deposited CdS layers with t hicknesses ranging between 0.05 and 0.12 μm and RF-magnetron-sputtered ITO and ZnO films have been independently analysed before the study of the combined materials. A CdS thickness below 0.1 μm has been found to be optimal for avoiding the adhesi on of large solution particles from the chemical bath, and thus for achieving a homogeneous CdS layer useful as a polycrystalline substrate to improve the transparent conductive oxide (TCO) grain size.