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Coordination mechanism of cyanine dyes on the surface of core@active shell β-NaGdF$_{4}$:Yb$^{3+}$,Er$^{3+}$ nanocrystals and its role in enhancing upconversion luminescence

Beygi Nasrabadi, Hossein; Madirov, Eduard; Popescu, Radian; Štacková, Lenka; Štacko, Peter; Klán, Petr; Richards, Bryce S.; Hudry, Damien; Turshatov, Andrey

Abstract:
The sensitization of lanthanide-doped upconversion nanocrystals (UCNCs) using organic dyes with a broad and intense optical absorption is an interesting approach for efficient excitation-energy harvesting and enhancing the upconversion luminescence of such UCNCs. In this work, an ultrasmall (∼6.5 nm in diameter) β-NaGdF$_{4}$:Yb$^{3+}$,Er$^{3+}$ core and related core@shell UCNCs were sensitized using six NIR-excitable cyanine dyes with a wide range of functional groups and optical properties. The greatest UC enhancement of 680-times was observed for the conjugate between the Cy 754 dye and β-NaGdF$_{4}$:Yb$^{3+}$,Er$^{3+}$@NaGdF$_{4}$:10%Yb$^{3+},30%Nd$^{3+} core@shell UCNCs excited using a 754 nm laser. The enhancement was estimated relative to NaGdF$_{4}$:Yb$^{3+}$,Er$^{3+}$@NaGdF$_{4}$:10%Yb$^{3+},30%Nd$^{3+} core@shell UCNCs capped with oleic acid and excited using a similar intensity (75 W cm$^{-2}$) of a 980 nm laser. UC intensity measurements for identical dye-sensitized UCNCs carried out in methanol and in deuterated methanol under argon, as well as in air, allowed us to reveal the connection of the dye triplet states with UCNC sensitization as well as of the hydroxyl groups with quenching of the excited states of lanthanide ions. ... mehr


Verlagsausgabe §
DOI: 10.5445/IR/1000140111
Veröffentlicht am 17.11.2021
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Mikrostrukturtechnik (IMT)
Lichttechnisches Institut (LTI)
Laboratorium für Elektronenmikroskopie (LEM)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 2050-7526, 2050-7534
KITopen-ID: 1000140111
HGF-Programm 38.01.05 (POF IV, LK 01) Simulations, Theory, Optics and Analytics (STOA)
Erschienen in Journal of materials chemistry / C
Verlag Royal Society of Chemistry (RSC)
Vorab online veröffentlicht am 21.09.2021
Nachgewiesen in Web of Science
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