title: Manipulating the Interfacial Energetics of n-type Silicon Photoanode for Efficient Water Oxidation.
abstract: The photoanodes with heterojunction behavior could enable the development of solar energy conversion, but their performance largely suffers from the poor charge separation and transport process through the multiple interfacial energy levels involved. The question is how to efficiently manipulate these energy levels. Taking the n-Si Schottky photoanode as a prototype, the undesired donor-like interfacial defects and its adverse effects on charge transfer in n-Si/ITO photoanode are well recognized and diminished through the treatment on electronic energy level. The obtained n-Si/TiOx/ITO Schottky junction exhibits a highly efficient charge transport and a barrier height of 0.95 eV, which is close to the theoretical optimum for n-Si/ITO Schottky contact. Then, the holes extraction can be further facilitated through the variation of surface energy level, with the NiOOH coated ITO layer. This is confirmed by a 115% increase in surface photovoltage of the photoanodes. Eventually, an unprecedentedly low onset potential of 0.9 V (vs RHE) is realized for water oxidation among n-Si photoanodes. For the water oxidation reaction, the n-Si/TiOx/ITO/NiOOH photoanode presents a charge separation efficiency up to 100% and an injection efficiency greater than 90% at a wide voltage range. This work identifies the important role of interfacial energetics played in photoelectrochemical conversion.
authors.forename: Tingting
authors.initials: T
authors.lastname: Yao
authors.affiliation: University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Ruotian
authors.initials: R
authors.lastname: Chen
authors.affiliation: International Iberian Nanotechnology Laboratory (INL) , Avenida Mestre Jose Veiga, Braga 4715-330, Portugal.
authors.forename: Junjie
authors.initials: J
authors.lastname: Li
authors.forename: Jingfeng
authors.initials: J
authors.lastname: Han
authors.forename: Wei
authors.initials: W
authors.lastname: Qin
authors.affiliation: University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Jingying
authors.initials: J
authors.lastname: Shi
authors.forename: Fengtao
authors.initials: F
authors.lastname: Fan
authors.forename: Can
authors.initials: C
authors.lastname: Li