DEVELOPMENT AND PERFORMANCE EVALUATION OF LEAD-FREE SILVER PASTES OPTIMIZED VIA DESIGN OF COMPOSITION FOR FABRICATION OF SCREEN-PRINTED SI SOLAR CELLS HAVING HIGH FILL FACTORS

초록

Screen-printed n+-p-p+ solar cells were fabricated on Cz single crystalline Si material, with a 45Ω/□ emitter and PECVD SiNx antireflective coating with a thickness of 700Å, using different Ag pastes and commercial-leaded reference paste (CN33-462, Ferro Corp., OH). Ag and Al contacts were co-fired using the mass production line of 30Mwp/year level (KPE Co., Ltd. Korea) equipped with conveyer furnace systems (Centrotherm thermal solution GmbH & Co. KG). The average results for single crystalline Si solar cells (156cm2) are: Isc = 5.014A, Voc = 0.623V, Rs = 0.0089Ω, Rsh = 9.8Ω, FF = 0.768, Eff = 16.31%. Rsh and fill factor values of fabricated cells were slightly higher when compared with the commercial-leaded Ag paste, although cells were fabricated by metallizing the lead-free silver pastes. For the lead-free Ag paste used in this study, moreover, the line pattern continuity is retained with improved edge definition in sharp contrast to that of reference Ag paste. Average value of Rs was also equivalent to approximately that of the leaded Ag paste.