Photovoltaic device requires light-absorbing materials that are highly efficient, low cost, lightweight, and stable during operation. Here we demonstrate the use of a hydrogenated amorphous silicon (a-Si:H) top cell and a crystal silicon heterojunction (HIT) bottom cell to form a double junction solar cell with a high open circuit voltage (V-OC), which is potentially functioned in the solar-to-hydrogen generation process and the replacement of chemical battery. Our photovoltaic device shows a high overall V-OC of 1.561 V and a short current density of over 14 mA/cm(2), which outperforms all other reported pure silicon-based double-junction solar cells. The newly developed a-Si:H/HIT double-junction solar cells hold the promise for some potential applications.