We are developing a monolithic Photo-Electrochemical (PEC) device that can directly convert solar energy to hydrogen by water splitting without electricity. This is called Solar Hydrogen. We have designed an innovative multilayer thin film architecture of earth-abundant semiconductors for photocathodes and photoanodes to ensure high light absorption and charge collection efficiencies. We plan to use this proprietary design to develop an efficient, robust, cost-effective, and scalable Photo-electrochemical (PEC) device.