Twenty-two percent efficiency HIT solar cell

We have achieved the world's highest solar cell conversion efficiency of 22.3% (Voc: 0.725 V, Isc: 3.909 A, FF: 0.791, total area: 100.5 cm2, confirmed by AIST) by using a heterojunction with intrinsic thin layer (HIT) structure. This is the world's first practical-size (>100 cm2) silicon solar cell that exceeds a conversion efficiency of 22% as a confirmed value. This high efficiency has been achieved mainly due to improvements in a-Si:H/c-Si hetero-interface properties and optical confinement.The excellent a-Si:H/c-Si hetero-interface of the HIT structure enables a high Voc of over 0.720 V and results in better temperature properties. In order to reduce the power-generating cost, we are now investigating numerous technologies to further improve the conversion efficiency, especially the Voc, of HIT solar cells, with the aim of achieving 23% efficiency in the laboratory by 2010.