Preparation And Studying Of High Efficiency CIGS Thin-film Solar Cells Based On Glass Substrate

Mo thin-films were prepared by magnetron sputtering metod with different discharge powers and working pressures for the application in Cu(In1-xGax)Se2(CIGS) thin film solar cells as back contacts. Properties of these Mo thin films were systematically investigated. It was found that the dynamic deposition rate increased with the increasing discharge power while decreased with the increasing working pressure. The highest dynamic deposition rate of 15.1 nm m/min was achieved for the Mo thin film deposited at the discharge power of 1200 W and at the working pressure of 0.15 Pa. The achieved lowest resistivity of 3.7 × 10-5 ? cm was attributed to the large grains in the compact thin film. The discharge power and working pressure had great influence on the sputtered Mo thin films. High efficiency of 12.5% was achieved for the CIGS thin film solar cells with Mo electrodes prepared at 1200 W and low working pressures.CIGS thin-films were deposited on SLG/Mo substrates with 3-stage co-evaporation process, the effect of CGI, GGI and second & third step substrate temperature on CIGS absorbers and CIGS thin-film solar cells were studied systemically.It was found that the Raman peak and XRD peaks of CIGS absorber moved to left with the increasing CGI. The grain size of CIGS absorber increased with the increasing CGI can be attributed to the fact that CIGS films experience liquid-phase-assisted recrystalline process. By testing I-V curve, it was found that Open circuit voltage(Voc), short-circuit current density(Jsc) and conversion efficiency of CIGS tin-film solar cells increased with the increasing CGI at first and decreases finally. The highest conversion efficiency solar cell was achieved at the CGI of 0.873.The Raman peak and XRD peaks of CIGS absorber moved to right with increasing GGI. The grain size of CIGS absorber decreased with the increasing GGI as In atom diffused more quickly than Ga in the process of depositing CIGS absorbers. It was found that the Voc increased with the increasing GGI but the FF and Jsc decreased. The efficiency of CIGS thin-film solar cells decreased obviously while GGI was larger than 0.324.The half band width(FWHM) of CIGS absorber's(112) XRD peak decreased with the increasing second & third step substrate temperature and the grain size increased. By testing I-V curve of CIGS thin-film solar cells with different second & third step substrate temperature, we found that Voc, Jsc and efficiency increased with the increasing second & third step substrate temperature at first and decreased at last. The FF increased with increasing second & third substrate temperature all the time. The highest conversion efficiency solar cells was achieved while the second & third step substrate temperature was 620 ?.By further optimizing material and device properties, the highest conversion efficiency CIGS thin-film solar cells had reached to16.07%.