Facile and cost-effective technique to control europium oxidation states in glassy fluorophosphate matrices with tunable photoluminescence

Agata Jarocka; Bartosz Fetliński; Paweł Dębowski; Tomasz K Pietrzak; Kacper Jurak; Marek Wasiucionek

doi:10.1038/s41598-022-21981-z

Facile and cost-effective technique to control europium oxidation states in glassy fluorophosphate matrices with tunable photoluminescence

Sci Rep. 2022 Nov 5;12(1):18774. doi: 10.1038/s41598-022-21981-z.

Authors

Agata Jarocka¹, Bartosz Fetliński², Paweł Dębowski³, Tomasz K Pietrzak³, Kacper Jurak⁴, Marek Wasiucionek³

Affiliations

¹ Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland. agata.jarocka.dokt@pw.edu.pl.
² Faculty of Electronics and Information Technology, Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland.
³ Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland.
⁴ Department of Electrochemistry, Corrosion and Material Engineering, Gdansk University of Technology, Narutowicza 11/12, 80-233, Gdansk, Poland.

Abstract

Inorganic fluorophosphate glasses doped with Eu[Formula: see text]/Eu[Formula: see text] are potential candidates for phosphors for commercial white LEDs. This report presents a fast, inexpensive and effective method of controlling the relative concentrations of Eu[Formula: see text]/Eu[Formula: see text] photoluminescent centers in these glasses. The technique consists of a fast quenching of the melt of initial reagents under appropriate conditions. Eu[Formula: see text]/Eu[Formula: see text] ratio was controlled by carrying out the melting under a reducing atmosphere at a temperature between 1000 and 1200 [Formula: see text]C for periods of 5 to 15 minutes. The reducing atmosphere was provided by a 'double crucible' technique and did not require special gas lines during the synthesis. The samples were studied by several complementary experimental methods (X-ray diffractometry-XRD, X-ray photoelectron spectroscopy-XPS, photoluminescence-PL-and photoluminescence excitation-PLE-spectroscopies as well as optical transmission spectroscopy). It was shown that the syntheses resulted in amorphous materials with different relative Eu[Formula: see text]/Eu[Formula: see text] concentration ratios, strongly dependent on the preparation conditions: the temperature and the time of melting in a reducing atmosphere. Moreover, changes in these ratios strongly affected the materials' PL and PLE spectra. Demonstration of reproducible smooth transition from amaranth to blue luminescence color, with white in between, was the most spectacular result of this work.