A rhodamine-based sensing probe excited by upconversion NaYF4:Yb3+/Er3+ nanoparticles: The realization of simple Cu(II) detection with high sensitivity and unique selectivity

Abstract In this paper, upconversion nanoparticles of β-NaYF 4 :Yb 3+ /Er 3+ and a rodamine derivative of 2-amino-3′,6′-bis(ethylamino)-2′,7′-dimethyl-3′,9a′-dihydrospiro[isoindoline-1,9′-xanthen]-3-one (referred as Rd-NH 2 ) were constructed and fully characterized. The energy transfer process between β-NaYF 4 :Yb 3+ /Er 3+ and Rd-NH 2 was also investigated. Data analysis suggests that the upconversion emission from β-NaYF 4 :Yb 3+ /Er 3+ can efficiently excite Rd-NH 2 . Using this upconversion emission as an excitation source and Rd-NH 2 as a sensing probe, their sensing behavior towards Cu 2+ was investigated. It was found that β-NaYF 4 :Yb 3+ /Er 3+ :Rd-NH 2 system showed linear response towards Cu 2+ in the range of 2–14 μM. In addition, β-NaYF 4 :Yb 3+ /Er 3+ :Rd-NH 2 system processed good selectivity towards Cu 2+ and high chemostability, making β-NaYF 4 :Yb 3+ /Er 3+ :Rd-NH 2 a promising sensing system towards Cu 2+ .