The Approaches for High Efficiency HITTM Solar Cell with Very Thin (<100 µm) Silicon Wafer over 23%

Abstract

In order to reduce the production cost of crystalline silicon-based solar cells, it is important to improve the conversion efficiency with thinner crystalline silicon wafers. We reported an excellent conversion efficiency of 22.8% with a thin wafer of 98 μm for the HIT (Heterojunction with Intrinsic Thin-layer) solar cell in 2009. By examining the loss analysis of the parameters for a 22.8% HIT solar cell, we improved the optical and electrical properties of the transparent conductive oxide (TCO) layer, the metal grid electrode and the window layers. As a result, we have achieved the world’s top level conversion efficiency of 23.7% (Voc: 0.745 V, Isc: 39.38 mA/cm2, FF: 80.9%, 100.7 cm2) with a thin wafer of 98 μm at the R&D stage.