Solar cell

A solar cell comprising:

• a substrate;
• a first conductive type region which is positioned at a front surface of the substrate and has a first conductive type;
• a second conducive type region which is positioned at a back surface opposite the front surface of the substrate and has a second conductive type different from the first conductive type;
• a front passivation region including a plurality of layers which are sequentially positioned on the first conductive type region;
• a back passivation region including a plurality of layers which are sequentially positioned on the second conductive type region;
• a front electrode part which passes through the front passivation region and is connected to the first conductive type region, wherein the front electrode part comprises a plurality of front electrodes that are apart from each other and a front bus bar connecting the plurality of front electrodes;
• and
• a back electrode part which passes through the back passivation region and is connected to the second conductive type region, wherein the back electrode part comprises a plurality of back electrodes that are apart from each other and a back bus bar connecting the plurality of back electrodes,
• wherein the front passivation region includes the plurality of layers formed of different materials from each other and including a first aluminum oxide layer and a first silicon nitride layer, and the back passivation region includes the plurality of layers formed of different materials from each other and including a second aluminum oxide layer and a second silicon nitride layer, and
• wherein a thickness of the first silicon nitride layer is greater than a thickness of the first aluminum oxide layer, and a thickness of the second silicon nitride layer is greater than a thickness of the second aluminum oxide layer.