Breaking the Nd3+-sensitized upconversion nanoparticles myth about the need of onion-layered structures

Abstract

Up to now, most strategies to build efficient 800 nm-light responsive upconversion nanoparticles (UCNPs) have included onion-layered structures, in which Nd³⁺ is confined within the inorganic crystal structure of at least one layer. We report here an easy room-temperature modular preparation of core–shell UCNPs consisting of NaYF₄:Yb,Er(Tm)/NaYF₄ (UC_CS) with Nd³⁺ anchored at the organic capping by using cucurbituril[7] (CB[7]) as an adhesive. Strikingly, excitation at 800 nm effectively triggers the upconversion emission of UC_CS@CB[7]@Nd nanohybrids.