Efficiency Improvement by Selective Emitter Solar Cells,Dr. Jianhua Zhao Vice Chairman,President and Chief Scientist China Sunergy Nanjing, China,The Structure of Selective Emitter Cells,Metal grid,Rear metal,SE Cell Structure,Cell efficiency,The electrical performance of 125mm X 125mm mono c-Si SE cells, as measured by Fraunhofer Institute of Solar Energy Systems, under STC 1000W/m2, AM1.5 global spectrum, at 25C.,Electrical Performance of SE Cells,The illustrated diagram is cited from the testing report of Fraunhofer ISE.,A = 148.81 cm2 Voc = 628 mV Isc = 5.33 A FF = 78.7 % Effic. = 17.8 % PMPP = 2.638 W,The Achievements obtained from SE Cells,Excellent electrical performance of SE cells,The Achievements obtained from SE Cells,Excellent electrical performances of SE cells,Due to the light diffusion on the illuminated emitter area, the SE Cells demonstrated very higher Voc and Isc Due to the heavy diffusion on the metal contact area, the SE Cells demonstrated excellent high FF,Excellent electrical performances of SE cells,The energy conversion efficiencies of SE cells are between 17.0% and 18.0% , the average efficiency is around 17.5 % . When these SE Cells were encapsulated into modules , they produced power as high as 185 W . SE Cells have very high Rsh, and very low reverse current density.,The Achievements obtained from SE Cells,Very low reverse current The reverse current of cells made by high quality wafers (125mm*125mm) were extremely low. Mostly the reverse current was in the range of 20mA to 30mA. And even when the wafers quality are relatively poor, the reverse current were merely 100mA to 200mA. Excellent performance under low lighting , low hot spot effect,The Achievements obtained from SE Cells,Excellent electrical performances of SE cells,The low degradation under the sunlight exposure According to the preliminary testing, the degradation of the power output from the SE Cell before encapsulation was less than 1.5%, this degradation is much less than conventional cells:,The Achievements obtained from SE Cells,The Advantages during the manufacturing of SE Cells.,Not picky at wafer qualities. The average energy conversion efficiency was always higher than 16.8% from the cells made of relatively poor quality wafers The average energy conversion efficiency were between 17.5% and 18% from the cells made of high quality wafers. Uniform cell performance with stable processing control The process is relatively easy to control,The Achievements obtained from SE Cells,SE cells have been successfully applied into commercial production and reached full capacity within a couple of weeks. The first production line was established in China Sunergy in mid November, 2007. the cell performances from the production line are better than the cell from trial production within one week since production commence. The daily production is 20 thousand cells before the end of November. China Sunergy produced 2MW SE Cells with the energy conversion efficiency higher than 17% in 2007. China Sunergy will have five SE Cell production lines in August, 2008, and will provide our customers with more and more high quality products.,The Achievements obtained from SE Cells,Thanks!,