Fast and intense green emission of Tb3+ in borosilicate glass modified by Cu+

Abstract

We present photoluminescence properties of Tb3+ doped borosilicate glasses modified by Cu+. Around 5-time enhanced emission at 541 nm due to the superposed emission of Tb3+ and Cu+ is observed under the deep UV excitation. Excitation spectra demonstrate a greatly increased absorption of Tb3+ ions in the deep UV region towards the Cu+ excitation band, while the shortened Cu+ emission lifetime of glasses in association with presence of Tb3+ ions implies an energy transfer process from Cu+ to Tb3+ ions. Meanwhile, the Tb3+ emission lifetime is significantly shortened from the conventional millisecond level (~4 ms) to the microsecond regime up to around 90μs. This most likely starts with the role of Cu+ as a co-activator by initiating the d-f orbital hybridization process via an interaction with Tb3+, thus relaxing the spin forbidden transition of Tb3+ ions to the partially allowed one. Moreover, combination of emissions from Cu+ and Tb3+ ions generates a composite green emission with adjustable CIE (Commission Internationale de L'Eclairage) chromaticity coordinates achievable by co-doping Cu+/Tb3+ in the different ratio and/or altering the excitation wavelength from deep UV to near UV region.