title: Enhanced Photocurrent of Transparent CuFeO2Photocathodes by Self-Light-Harvesting Architecture.
abstract: Efficient sunlight-driven water-splitting devices can be achieved by using an optically and energetically well-matched pair of photoelectrodes in a tandem configuration. The key for maximizing the photoelectrochemical efficiency is the use of a highly transparent front photoelectrode with a band gap below 2.0 eV. Herein, we propose two-dimensional (2D) photonic crystal (PC) structures consisting of a CuFeO2-decorated microsphere monolayer, which serve as self-light-harvesting architectures allowing for amplified light absorption and high transparency. The photocurrent densities are evaluated for three CuFeO22D PC-based photoelectrodes with microspheres of different sizes. The optical analysis confirmed the presence of a photonic stop band that generates slow light and at the same time amplifies the absorption of light. The 410 nm sized CuFeO2-decorated microsphere 2D PC photocathode shows an exceptionally high visible light transmittance of 76.4% and a relatively high photocurrent of 0.2 mA cm-2at 0.6 V vs a reversible hydrogen electrode. The effect of the microsphere size on the carrier collection efficiency was analyzed by in situ conductive atomic force microscopy observation under illumination. Our novel synthetic method to produce self-light-harvesting nanostructures provides a promising approach for the effective use of solar energy by highly transparent photocathodes.
authors.affiliation: Department of Materials Science and Engineering, Yonsei University , 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Yunjung
authors.initials: Y
authors.lastname: Oh
authors.affiliation: Department of Materials Science and Engineering, Yonsei University , 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Wooseok
authors.initials: W
authors.lastname: Yang
authors.affiliation: Department of Materials Science and Engineering, Yonsei University , 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Jimin
authors.initials: J
authors.lastname: Kim
authors.affiliation: Advanced Materials Division, Korea Research Institute of Chemical Technology (KRICT) , 141 Kajeong-ro, Yuseong, Daejeon 305-600, Republic of Korea.
authors.forename: Sunho
authors.identifier: http://orcid.org/0000-0002-5969-1614
authors.initials: S
authors.lastname: Jeong
authors.affiliation: Department of Materials Science and Engineering, Yonsei University , 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Jooho
authors.identifier: http://orcid.org/0000-0002-6685-9999
authors.initials: J
authors.lastname: Moon
keywords: CuFeO2; front photoelectrode; self-light-harvesting; transparent photocathode; two-dimensional photonic crystal