Photoluminescence of Eu 3+ -doped glasses with Cu 2+ impurities José A. Jiménez ⇑ Department of Chemistry, University of North Florida, Jacksonville, FL 32224, USA highlights  Optical properties of phosphate glasses containing copper (II) and europium (III) assessed.  Inﬂuence of Cu 2+ on Eu 3+ photoluminescence investigated through temperature-dependent studies.  Eu 3+ emission intensity and decay dynamics correlated with Cu 2+ impurities concentration.  Eu 3+ ? Cu 2+ non-radiative energy transfer evaluated and discussed. graphical abstract article info Article history: Received 20 September 2014 Received in revised form 27 February 2015 Accepted 2 March 2015 Available online 9 March 2015 Keywords: Energy transfer Luminescence Optical properties Rare earths abstract Glasses activated with Eu 3+ ions are attractive as luminescent materials for various photonic applications. Co-doping with copper has been proposed for enhancing material optical properties, but the quenching effect of Cu 2+ impurities on Eu 3+ emission in glass remains largely unexplored. In this work, Eu 2 O 3 /CuO- containing barium–phosphate glasses have been prepared by the melt-quench method, and the Eu 3+ photoluminescence (PL) quenching resulting from Eu 3+ ? Cu 2+ energy transfer was evaluated. Optical absorption spectroscopy showed that with the increase in CuO concentration the Cu 2+ absorption band resonant with Eu 3+ emission (e.g. 5 D 0 ? 7 F 2 transition around 615 nm) developed steadily. As a result, Eu 3+ PL was progressively quenched. Evaluation of the quenching constants as a function of temperature in the 298–673 K range showed differences basically within experimental error, consistent with a reso- nant transfer and lack of phonon-assisted processes. Moreover, analysis of the Eu 3+ emission decay dynamics revealed a strong correlation between the decay rates and Cu 2+ impurity levels. Results imply that for practical applications the levels of Cu 2+ in Eu 3+ /Cu + -activated glasses should be reduced if not removed as these will signiﬁcantly limit device efﬁciency. Ó 2015 Elsevier B.V. All rights reserved. Introduction Europium-doped glasses are attractive as optical materials given their distinctive properties valuable for color displays, lasers and solid-state lighting applications [1–4]. Recently, co-doping with monovalent copper species has been proposed as strategy for enhancing the luminescent properties of Eu 3+ -activated glasses [2]. On the other hand, it has been reported that divalent copper can effectively suppress europium photoluminescence (PL) in glass as considerable spectral overlap occurs between Cu 2+ absorption and Eu 3+ emission (e.g. 5 D 0 ? 7 F 2 transition) [5]. Indeed, the under- lying energy transfer has been successfully exploited in solution phase for the development of analytical methods for the determination of copper (II) [6,7]. However, detailed studies on the inﬂuence of divalent copper impurities in Eu/Cu co-doped glasses are still lacking. Such evaluations are necessary as Cu 2+ could potentially limit the efﬁciency of the Eu 3+ -activated glasses for optical device applications as is the case for Nd-doped laser glass [8]. Accordingly, the present work investigates on the http://dx.doi.org/10.1016/j.saa.2015.03.047 1386-1425/Ó 2015 Elsevier B.V. All rights reserved. ⇑ Tel.: +1 904 620 1963; fax: +1 904 620 3535. E-mail address: jose.jimenez@unf.edu Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 145 (2015) 482–486 Contents lists available at ScienceDirect Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa