Energy-Cascaded Upconversion in an Organic Dye-Sensitized Core/Shell Fluoride Nanocrystal.
Lanthanide-doped upconversion nanoparticles hold promises for bioimaging, solar cells, and volumetric displays. However, their emission brightness and excitation wavelength range are limited by the weak and narrowband absorption of lanthanide ions. Here, we introduce a concept of multistep cascade energy transfer, from broadly infrared-harvesting organic dyes to sensitizer ions in the shell of an epitaxially designed core/shell inorganic nanostructure, with a sequential nonradiative energy transfer to upconverting ion pairs in the core. We show that this concept, when implemented in a core-shell architecture with suppressed surface-related luminescence quenching, yields multiphoton (three-, four-, and five-photon) upconversion quantum efficiency as high as 19% (upconversion energy conversion efficiency of 9.3%, upconversion quantum yield of 4.8%), which is about ~100 times higher than typically reported efficiency of upconversion at 800 nm in lanthanide-based nanostructures, along with a broad spectral range (over 150 nm) of infrared excitation and a large absorption cross-section of 1.47 × 10(-14) cm(2) per single nanoparticle. These features enable unprecedented three-photon upconversion (visible by naked eye as blue light) of an incoherent infrared light excitation with a power density comparable to that of solar irradiation at the Earth surface, having implications for broad applications of these organic-inorganic core/shell nanostructures with energy-cascaded upconversion.
Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York , Buffalo, New York 14260, United States.|School of Chemical Engineering and Technology, Harbin Institute of Technology , Harbin, Heilongjiang 150001, P. R. China.
Guanying
G
Chen
Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York , Buffalo, New York 14260, United States.
Jossana
J
Damasco
Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York , Buffalo, New York 14260, United States.|School of Chemical Engineering and Technology, Harbin Institute of Technology , Harbin, Heilongjiang 150001, P. R. China.
Hailong
H
Qiu
Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York , Buffalo, New York 14260, United States.|School of Chemical Engineering and Technology, Harbin Institute of Technology , Harbin, Heilongjiang 150001, P. R. China.
Wei
W
Shao
Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York , Buffalo, New York 14260, United States.
Tymish Y
TY
Ohulchanskyy
Department of Theoretical Chemistry and Biology, Royal Institute of Technology , S-10691 Stockholm, Sweden.|Tomsk State University , 36 Lenin Avenue, 634050 Tomsk, Russian Federation.
Rashid R
RR
Valiev
Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School , Worcester, Massachusetts 01605, United States.
Xiang
X
Wu
Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School , Worcester, Massachusetts 01605, United States.
Gang
G
Han
Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York , Buffalo, New York 14260, United States.
Yan
Y
Wang
School of Chemical Engineering and Technology, Harbin Institute of Technology , Harbin, Heilongjiang 150001, P. R. China.
Chunhui
C
Yang
Department of Theoretical Chemistry and Biology, Royal Institute of Technology , S-10691 Stockholm, Sweden.
Hans
H
Ågren
Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York , Buffalo, New York 14260, United States.|Department of Chemistry, Korea University , Seoul 136-701, Korea.
Paras N
PN
Prasad
Core/Shell; Dye-Sensitized; Lanthanide; Nanoparticles; Rare-Earth; Upconversion