Lanthanide-doped fluoride core/multishell nanoparticles for broadband upconversion of infrared light

• The authors introduce a novel multilayer core/shell design to broadly upconvert infrared (IR) light at many discrete wavelengths into visible or near-IR (NIR) emissions. It utilizes hexagonal-phase core/multishell NaYF4:10%Er3+@NaYF4@NaYF4:10%Ho3+@NaYF4@NaYF4:1%Tm3+@NaYF4 nanoparticles, where the active core as well as each active shell upconvert a distinct set of IR wavelength. The inert NaYF4 layers in between these upconverting domains efficiently suppress the detrimental cross-relaxation processes between different types of lanthanide ions, thus yielding about two times more efficient upconversion photoluminescence than the counterpart NaYF4:10%Er3+@NaYF4:10%Ho3+ @NaYF4:1%Tm3+@NaYF4 without the inert NaYF4 layers, and about one order of magnitude higher than the core/shell NaYF4:10%Er3+, 10%Ho3+, 1%Tm3+@NaYF4 nanoparticles without spatially isolating the Er3+, Ho3+, and Tm3+ ions. These core/multishell nanoparticles can be excited at ≈1120-1190 nm (due to Ho3+), ≈1190-1260 nm (due to Tm3+), and ≈1450-1580 nm (due to Er3+), collectively covering a broad spectral range of about 270 nm in the IR range that can be very useful for IR photosensitization of solar cells.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

Nyckelord

Core/shell

Cross-relaxation

Lanthanide elements

Nanoparticles

Solar materials

Upconversion

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