Carrier-selective p- and n-contacts for efficient and stable photocatalytic water reduction

Abstract

The successful realization of carrier-selective contacts for crystalline silicon (c-Si) based device for photocatalytic hydrogen production has been demonstrated. The proposed TiO2 protected carrier-selective contacts resemble a metal-oxide-semiconductor configuration, including a highly-doped nanocrystalline silicon (nc-Si) and a tunnel oxide, thereby form a heterostructure with the c-Si substrate. By substituting conventional pn+-junction Si by c-Si/SiOX/nc-Si structure for both front and back contacts we demonstrate a 16% increase in photovoltage (an open circuit voltage of 584mV under AM 1.5G conditions). TiO2 protected carrier-selective photoelectrodes showed excellent long-term durability in acidic aqueous solution having stable photocurrent output for more than 40days, implying that the proposed carrier-selective contact is a promising configuration to substitute for the conventional pn-junction based c-Si photocathodes.