Solar cell

A bifacial solar cell comprising:

• an n type silicon substrate;
• a p type emitter layer positioned at a first surface of the n type silicon substrate;
• a plurality of first electrodes locally positioned on the p type emitter layer and electrically connected to the p type emitter layer;
• a first aluminum oxide layer positioned on the p type emitter layer;
• a first silicon oxide layer formed at an interface between the first aluminum oxide layer and the p type emitter layer, the first silicon oxide layer having a thickness of about 1 nm to 3 nm;
• a first anti-reflection layer positioned on the first aluminum oxide layer and containing silicon nitride (SiNx);
• a back surface field layer positioned on a rear surface of the n type silicon substrate;
• a second aluminum oxide layer on the rear surface of the n type silicon substrate;
• a second silicon oxide layer formed at an interface between the second aluminum oxide layer and the rear surface of the n type silicon substrate, the second silicon oxide layer having a thickness of about 1 nm to 3 nm;
• a second anti-reflection layer positioned on the second aluminum oxide layer and containing silicon nitride (SiNx);
• and
• a plurality of second electrodes directly contacting the back surface field layer through the second anti-reflection layer, the second aluminum oxide layer and the second silicon oxide layer,
• wherein the plurality of first electrodes and the plurality of second electrodes include silver (Ag), the plurality of first electrodes further include aluminum (Al), and the plurality of second electrodes do not include aluminum (Al),
• wherein the plurality of first electrodes are formed of a first conductive paste including a glass frit and a mixture (Ag:Al) of silver (Ag) and aluminum (Al), and the plurality of second electrodes are formed of a second conductive paste including a glass frit and silver (Ag), and
• wherein the p type emitter layer includes a first doped region, which is lightly doped with impurities of the p type, and a second doped region formed locally, which is more heavily doped than the first doped region with impurities of the p type.