title: Simultaneous multiple wavelength upconversion in a core-shell nanoparticle for enhanced near infrared light harvesting in a dye-sensitized solar cell.
abstract: The efficiency of most photovoltaic devices is severely limited by near-infrared (NIR) transmission losses. To alleviate this limitation, a new type of colloidal upconversion nanoparticles (UCNPs), hexagonal core-shell-structured β-NaYbF4:Er(3+)(2%)/NaYF4:Nd(3+)(30%), is developed and explored in this work as an NIR energy relay material for dye-sensitized solar cells (DSSCs). These UCNPs are able to harvest light energy in multiple NIR regions, and subsequently convert the absorbed energy into visible light where the DSSCs strongly absorb. The NIR-insensitive DSSCs show compelling photocurrent increases through binary upconversion under NIR light illumination either at 785 or 980 nm, substantiating efficient energy relay by these UCNPs. The overall conversion efficiency of the DSSCs was improved with the introduction of UCNPs under simulated AM 1.5 solar irradiation.
authors.affiliation: Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology (KTH) , 10691 Stockholm, Sweden.
authors.forename: Chunze
authors.initials: C
authors.lastname: Yuan
authors.forename: Guanying
authors.initials: G
authors.lastname: Chen
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.forename: Jossana A
authors.initials: JA
authors.lastname: Damasco
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Ning
authors.forename: Hui
authors.initials: H
authors.lastname: Xing
authors.forename: Tianmu
authors.initials: T
authors.lastname: Zhang
authors.forename: Licheng
authors.initials: L
authors.lastname: Sun
authors.forename: Hao
authors.initials: H
authors.lastname: Zeng
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Cartwright
authors.forename: Paras N
authors.initials: PN
authors.lastname: Prasad
authors.forename: Hans
authors.initials: H
authors.lastname: Ågren
keywords: dye-sensitized solar cells; energy relay; nanoparticles; near-infrared; upconversion