Studies on optimisation of processing parameters for ultra-thin CdTe solar cell

Abstract

Ultra-thin solar cell devices can have many potential applications as top cells in tandem solar cells as well as power generating window material in buildings. Such applications require that ultra-thin layers should be easy to fabricate, have very high optical transparency to allow maximum light to pass through, generate high power and be low cost. CdTe based ultra-thin cells are suitable candidates for such applications. Less than 1 micron thick layers of CdTe can be high on transmittance and yet absorb good percentage of incident photons. Optical and electrical properties ultra-thin devices based on CdTe need to be investigated to examine its suitability for use in tandem cells or building materials. This research is focused on fabricating solar cells with increasingly thinner CdTe layer (< 1 μm) on glass based and flexible substrates. Low cost methods such as electrodeposition and chemical bath deposition were used to deposit solar cell layers. Computer Modeling was carried out to design and optimize the optical transparency and output power of the solar cells produced. Ultra-thin solar cells prepared by MOCVD had efficiency of 4.9 % for a 400 nm thin CdTe layer cell. Experimental results showed very good agreement with the modeling results. Use of Cd1-xZnxTe has an absorber material has also been investigated using modeling.