Optimized photoluminescence quantum yield in upconversion composites considering the scattering, inner-filter effects, thickness, self-absorption, and temperature

Jones, Callum M. S.; Biner, Daniel; Misopoulos, Stavros; Krämer, Karl W.; Marques-Hueso, Jose (2021). Optimized photoluminescence quantum yield in upconversion composites considering the scattering, inner-filter effects, thickness, self-absorption, and temperature. Scientific reports, 11(1), p. 13910. Springer Nature 10.1038/s41598-021-93400-8

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Optimizing upconversion (UC) composites is challenging as numerous effects influence their unique emission mechanism. Low scattering mediums increase the number of dopants excited, however, high scattering mediums increase the UC efficiency due to its non-linear power dependency. Scattering also leads to greater thermal effects and emission saturation at lower excitation power density (PD). In this work, a photoluminescence quantum yield (PLQY) increase of 270% was observed when hexagonal NaYF4:(18%)Yb3+,(2%)Er3+ phosphor is in air compared to a refractive indexmatched medium. Furthermore, the primary inner-filter effect causes a 94% PLQY decrease when the excitation focal point is moved from the front of the phosphor to 8.4 mm deep. Increasing this effect limits the maximum excitation PD, reduces thermal effects, and leads to emission saturation at higher excitation PDs. Additionally, self-absorption decreases the PLQY as the phosphor’s thickness increases from 1 to 9 mm. Finally, in comparison to a cuboid cuvette, a 27% PLQY increase occurs when characterizing the phosphor in a cylindrical cuvette due to a lensing effect of the curved glass, as supported by simulations. Overall, addressing the effects presented in this work is necessary to both maximize UC composite performance as well as report their PLQY more reliably.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Biner, Daniel, Krämer, Karl

Subjects:

500 Science > 530 Physics
500 Science > 540 Chemistry

ISSN:

2045-2322

Publisher:

Springer Nature

Language:

English

Submitter:

Karl Krämer

Date Deposited:

28 Dec 2021 11:49

Last Modified:

05 Dec 2022 15:55

Publisher DOI:

10.1038/s41598-021-93400-8

PubMed ID:

34230548

BORIS DOI:

10.48350/161871

URI:

https://boris.unibe.ch/id/eprint/161871

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