Photovoltaic modules processing of CdS/CdTe by CSVT in 40 cm2

We present in this work the fabrication of photovoltaic modules of the CdS/CdTe type, the first ones processed in Mexico in large area (40 cm² and contact area of 3 cm²); these photovoltaic modules are constituted of the n-type cadmium sulfide (CdS) semiconductor, as the window material, and the p-type cadmium telluride (CdTe) semiconductor as the absorbing material. The back contacts were deposited by vacuum thermal evaporation. The electrical characteristics were determined by the measurement of current on voltage I vs. V. Two independent series of photovoltaic modules have been processed: in the first series the CdS was processed by the technique of Chemical Bath Deposition (CBD), the CdTe was deposited by the conventional technique of Closed Spaced Vapor Transport and the device consists of a photovoltaic module constituted of 9 independent solar cells with approximate 3 cm² contact area. Of the total of these 9 solar cells, 6 have almost the same l-V characteristics in dark as well as in illumination AM1.5 (100 mW/cm²), with an average efficiency of 5.9 ± 0.3%, and the three remaining cells have approximately 3% of photovoltaic efficiency. The maximum power of each solar cell is of 18.5 mW. The power obtained by the prototype of photovoltaic module is approximately of 105 mW or 0.105 W in 18 cm², which could scale up to 58 W/m². The second series consists of photovoltaic modules, totally processed in a new CSVT system (completely designed, machined and assembled in our workshop and laboratory) including 9 interconnected solar cells to each another, with 3 cm² of contact area, approximately.