Fabrication and Characterization of Screen Printing Silicon Solar Cells

Autor: Yu-Fu Shen, 沈裕富
Rok vydání: 2008
Druh dokumentu: 學位論文 ; thesis
Popis: 96
Screen-printing technology for the manufacture of silicon solar cells is widely used in the photovoltaic industry today. The advantages of screen printing, compared with evaporation or plating techniques, include the suitability for automation, relatively simple and continuous processing, adaptability to modular construction for the actual production facility. Solar cells electrode metallization is a major efficiency-limiting and cost-determining step in solar cells processing. Ag thick film contacts are commonly used for the front side metallization of crystalline n+-Si emitter covered by a SiNx antireflection coating, A typical commercially available silver thick film paste consists of silver powder, glass frit and organics comprising binder, solvent and certain additives to ensure proper printing properties. The glass frit in Ag pastes plays a critical role in the screen-printing metallization process for industrial silicon solar cells. The glass frit in the Ag paste is the main factor that determines the contact resistance, silicon surface etching, and ultimately the overall surface performance. Nevertheless, screen-printing contact formation and current transport is not fully understood. Therefore, the aim of this study is find the best firing profile and low specific contact resistiveity. We have obtained a low resistivity ohmic contact for screen-printing solar cell. The lowest specific contact resistivity of screen-printing solar cell by rapid thermal annealing (RTA) process and measured by transfer length method (TLM). The lowest value of specific contact resistivity of Ag pastes for screen-printing solar cell was 7.98×10-5Ω-cm2 at 740℃. Two type screen-printing solar cell was fabricated in this study. All completed cells were tested under AM1.5 conditions and room temperature. A efficiency of 11.21% screen-printing solar cell with Ag paste/n+ -Si/p-Si/Al paste structure was obtained; the corresponding short circuit current density, open-circuit voltage, and fill factor were 29.43/cm2, 0.565V, 67.4%,respectively. In addition, A efficiency of 14.45% screen-printing solar cell using Ti/Pd/Ag/n+-Si/p-Si/Al paste structure was obtained; the corresponding short circuit current density, open-circuit voltage, and fill factor were 36.24mA/cm2, 0.58V, 68.63%, respectively.
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