TANDEM PHOTOELECTROCHEMICAL CELL FOR WATER DISSOCIATION

摘要

A tandem photoelectrochemical (PEC) cell including a nitride PEC semiconductor connected in series with a current matched photovoltaic (PV) Si solar cell that provides an internal biasing voltage. A low resistance tunnel junction is formed between the PEC semiconductor and PV cell. The tandem PEC cell is placed together with a counter electrode in contact with an aqueous solution, such that, when exposed to solar radiation, the PEC semiconductor utilizes high energy photons to split water while the PV cell utilizes low energy photons to bias the tandem PEC cell to eliminate the barrier between Fermi energy and redox potentials, thereby initiating the spontaneous dissociation of water in the aqueous solution into hydrogen and oxygen. The conduction band edge (CBE) for n-type PEC semiconductor is located in the vicinity of the Fermi stabilization energy to reduce the barriers for the charge transfer between the PEC semiconductor and the aqueous solution.