title: Eu3+amidst ionic copper in glass: Enhancement through energy transfer from Cu+, or quenching by Cu2+?
abstract: A barium-phosphate glass system doped with europium(III) and containing a high concentration of copper(I) together with a copper(II) remnant has been studied spectroscopically. The main object is to elucidate whether the orange-red emission of Eu3+ions succeeds through sensitization via luminescent Cu+ions or else is preferentially quenched by non-radiative transfer to Cu2+. A characterization of the melt-quenched glass was first performed by UV/Vis optical absorption,31P nuclear magnetic resonance and infrared absorption spectroscopy. A photoluminescence (PL) spectroscopy and emission decay dynamics assessment was subsequently performed. Despite the concentration of Cu+being estimated to be much higher than that of Cu2+, the data shows that quenching of Eu3+PL by Cu2+dominates. The lifetime analysis of emitting centers Cu+and Eu3+points to the origin of the manifestation being that the Eu3+→Cu2+non-radiative transfer rate responsible for the quenching is almost two times higher than that for the Cu+→Eu3+transfer accountable for the enhancement. Finally, an effort was made for the determination of Cu2+in the glass containing Cu+, Cu2+and Eu3+ions based on the Eu3+(5D0) emission decay rates. It was found to be in excellent agreement with the UV/Vis spectrophotometric approach, thus supporting the utility of Eu3+ions for optical sensing of copper(II) in the solid state.
authors.affiliation: Department of Chemistry, University of North Florida, Jacksonville, FL 32224, USA. Electronic address: jimenez.materials@gmail.com.
authors.forename: José A
authors.initials: JA
authors.lastname: Jiménez
keywords: Energy transfer; Glasses; Optical absorption; Photoluminescence spectroscopy