Solar cell

A solar cell comprising:

• a substrate of a first conductive type;
• an emitter region which is positioned at a front surface of the substrate and has a second conductive type different from the first conductive type;
• a back surface field region which is positioned at a back surface opposite the front surface of the substrate;
• a front passivation region including a plurality of layers which are sequentially positioned on the emitter region;
• a back passivation region including a plurality of layers which are sequentially positioned on the back surface field region;
• a front electrode part which passes through the front passivation region and is connected to the emitter 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;
• a back electrode part which passes through the back passivation region and is connected to the back surface field 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,
• wherein a stacked order of the plurality of layers of the front passivation region from the front surface of the substrate towards a front exterior of the solar cell is different from a stacked order of the plurality of layers of the back passivation region from the back surface of the substrate towards a back exterior of the solar cell, 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.