High-performance HIT solar cells for thinner silicon wafers

Abstract

We have been researching and developing HIT (Heterojunction with Intrinsic Thin-layer) solar cells to obtain high conversion efficiency. Last year, we updated the world's highest conversion efficiency, which was previously 22.3%, to 23.0% with a practical-sized HIT solar cell at the R&D stage. We have also been investigating the performance of thinner HIT solar cells using less than 100-μm-thick crystalline Si (c-Si) wafers in order to effectively reduce the production cost. By using improved technologies, we succeeded in gaining the high conversion efficiency of 22.8% in a HIT solar cell with a 98-μm-thick c-Si wafer and an excellent V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">oc</sub> of 743 mV at the R&D stage. The accomplishment of the 22.8% cell demonstrates that HIT solar cells are advantageous to the use of thinner Si wafers because of certain HIT solar cell features.