Large-scale solar cell

Small-area thin-film CdTe solar cells have been fabricated with sunlight-to-electricity conversion efficiencies near 16%, comparable to crystalline siUcon solar cells in large-scale manufacturing. Large-area monolithic integrated CdTe modules have been fabricated with efficiencies of ca 10%, comparable to crystalline siUcon modules commercially available. 

Schropp and Zeman [11] have classified current production systems for amorphous silicon solar cells. They argue that cost-effective production of solar cells on a large scale requires that the product of the deposition time needed per square meter and the depreciation and maintenance costs of the system be small. Low... 

The research effort in many laboratories around the world on the optimization of laboratory-scale (1-cm- area) cells has led to the development of large-area (1 m ) solar cell modules with an efficiency exceeding 10% [613,614]. In a module individual cells can be connected in series or parallel, depending on the desired... 

Ideally, all photons with a wavelength of about 900 nm or shorter should be harvested and converted to electric current. This limit is derived from thermodynamic considerations showing that the conversion efficiency of any single-junction photovoltaic solar converter peaks at approximately 33% near the threshold energy of lAeV.1 2 There are numerous ways to convert the solar radiation directly into electrical power or chemical fuel. The silicon solar cell is the most efficient in this respect. Nevertheless, the capital cost of such devices is not attractive for large-scale applications. 

Solar energy is difficult to be utilized due to its diluteness. In order to use it in a large scale, therefore, the irradiation must be collected. Especially when the conversion module is expensive (e.g., the Si solar cell), the collection and concentration of the solar energy is economically advantageous. 

Since the envisionaged application of a CD process in thin-fihn solar cells is a large-scale one, efforts have been made to optimize the deposition process used, particularly in minimizing the waste Cd-containing solutions. Dilute Cd solutions (ca. 1 mM), a flow system with filtration, and a heated substrate have been employed to this end. The heated substrate means that deposition occurs preferentially on the substrate rather than on the cooler walls of the deposition vessel. Also, ethylenediamine has been used as a complexant rather than the much more volatile ammonia. 

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