Electrochemical Preparation Of CdTe/CdS Heterojunctions And Their Photoelectric Properties

As the new energy-resource devices, solar cells have been attracting great attention due to their potential abilities in solving the growing energy crisis. In recent years, solar cells developed very fast. Although market share of cadmium telluride solar cells was still low compared to crystalline silicon solar cells, such cells have a significant cost advantage and attract extensive concern. How to improve conversion efficiency of the CdTe solar cells and reduce their costs further have become a new research hotspot. In this thesis, electrochemical method was adopted to prepare and assemble CdTe solar cells with different geometric heterostructures. And the photoelectric properties were detailedly investigated. The method not only simplifies the process but also reduces costs.Galvanostatic electrodeposited CdS thin films was on the ITO substrates, and potentiostatic electrodeposited CdTe thin films was then prepared to form a two-dimensional CdTe/CdS heterojunction structure. CdS nanorod arrays were successfully prepared by one step hydrothermal method on ITO substrates. Then potentiostatic electrodeposited CdTe thin films was prepared on CdS nanorod arrays film/ITO to form a three-dimensional CdTe/CdS nanorod arrays heterojunction. At last assemble the two heterojuction structures to form solar cells and research on their photoelectric properties, using carbon nanotube thin films as back electrode.Under the standard irradiation (AM 1.5,100 mW/cm2), the photoelectric properties of CdTe/CdS solar cells with planar heterojunction were as follows:Voc=0.294 V, Jsc=1.24 mA/cm2, FF=0.137, η=0.05%. The photoelectric properties of CdTe/CdS solar cells with three-dimensional nanorod arrays heterojunction were as follows: Voc=0.609 V,Jsc=3.16 mA/cm2, FF=0.257,η=0.495%. The open circuit voltage, short-circuit current density, conversion efficiency of CdTe/CdS solar cells with three-dimensional nanorod arrays heterojunction was 2 times,2.5 times,10 times as high as that of solar cells with two-dimensional heterojunction.