Title :
Improvement of Crystallinity and Solar Cell Efficiency of Spherical Silicon by Seeding Crystallization Techniques
Author :
Liu, Zhengxin ; Masuda, Atsushi ; Sakai, Kenji ; Asai, Koichi ; Kondo, Michio
Author_Institution :
Res. Center for Photovoltaics, Nat. Inst. of Adv. Ind. Sci. & Technol., Ibaraki
Abstract :
Silicon spheres were fabricated from melted silicon by dropping method. In order to improve the quality of silicon spheres, we developed a novel seeding crystallization technique for the solidification of silicon droplets in high-speed dropping. High-pure silicon powders were used as seeding source material. They were embedded into the silicon droplets by floating and confining within a specific region on the dropping route. Experimental results demonstrated that this method is very effective on improving the crystalline quality and on reducing the defects and dislocations of the silicon spheres. A solar cell module having about 4x lens concentrator was developed without polishing the spheres. A conversion efficiency of 11.3% under AM1.5, 100 mW/cm2 sunlight was achieved from single sphere with size of 1.0 mm in diameter
Keywords :
crystallisation; dislocations; drops; elemental semiconductors; silicon; solar cells; solidification; 11.3 percent; Si; conversion efficiency; dislocations; pure silicon powders; seeding crystallization; seeding source material; silicon droplets; solar cell efficiency; solar cell module; solidification; spherical silicon; Argon; Control systems; Crystallization; Etching; Furnaces; Laboratories; Photovoltaic cells; Powders; Silicon; Wavelength measurement;
Conference_Titel :
Photovoltaic Energy Conversion, Conference Record of the 2006 IEEE 4th World Conference on
Conference_Location :
Waikoloa, HI
Print_ISBN :
1-4244-0017-1
Electronic_ISBN :
1-4244-0017-1
DOI :
10.1109/WCPEC.2006.279423