title: Dual-functional CeO2:Eu3+ nanocrystals for performance-enhanced dye-sensitized solar cells.
abstract: Single-crystalline, octahedral CeO2:Eu3+ nanocrystals, successfully prepared using a simple hydrothermal method, were investigated to determine their photovoltaic properties in an effort to enhance the light-harvesting efficiency of dye-sensitized solar cells (DSSCs). The size of the CeO2:Eu3+ nanocrystals (300-400 nm), as well as their mirrorlike facets, significantly improved the diffuse reflectance of visible light. Excitation of the CeO2:Eu3+ nanocrystal with 330 nm ultraviolet light was re-emitted via downconversion photoluminescence (PL) from 570 to 672 nm, corresponding to the 5D0→7FJ transition in the Eu3+ ions. Downconversion PL was dominant at 590 nm and had a maximum intensity for 1 mol % Eu3+. The CeO2:Eu3+ nanocrystal-based DSSCs exhibited a power conversion efficiency of 8.36%, an increase of 14%, compared with conventional TiO2 nanoparticle-based DSSCs, because of the strong light-scattering and downconversion PL of the CeO2:Eu3+ nanocrystals.
authors.affiliation: School of Chemical and Biological Engineering, College of Engineering, Seoul National University , 599 Gwanak-ro, Gwanak-gu, Seoul 151-742, Korea.
authors.forename: Jongmin
authors.initials: J
authors.lastname: Roh
authors.forename: Sun Hye
authors.initials: SH
authors.lastname: Hwang
authors.forename: Jyongsik
authors.initials: J
authors.lastname: Jang
keywords: CeO2; CeO2:Eu3+; downconversion; dye-sensitized solar cell; europium; light-scattering; photoluminescence