From planar junction to local junction: A new structure design of amorphous/crystalline silicon heterojunction solar cells for high efficiency and low cost.

In order to obtain higher conversion efficiency and to reduce production cost for amorphous silicon/crystalline silicon (a-Si/c-Si) based heterojunction solar cells, a Heterojunction of Amorphous silicon and Crystalline silicon with Localized pn structure (HACL) has been designed. The potential performance of the HACL solar cell has been assessed by ATLAS simulation program. Its potential performance is compared with that of the Heterojunction with Intrinsic Thin film (HIT) and Heterojunction of Amorphous silicon and Crystalline silicon with Diffused junction (HACD) solar cells. The simulated results indicated that the conversion efficiency and the short-circuit current density of the HACL cell can reach to 28.18% and 43.06 mA/cm2, respectively, and are higher than that of the HIT and HACD cells. The main reasons for the great improvement are (1) to increase the light utilization rate on both sides of the cell and (2) to enhance the collection efficiency of the photocarriers. Moreover, the HACL structure can decrease the consumption of rare materials, such as indium, since the transparent conductive oxide (TCO) can be free in this structure. It is concluded that the HACL solar cell is a promising structure for high efficiency and low cost.