Highly Efficient Near-Infrared II Electrochemiluminescence from NaYbF4Core Mesoporous Silica Shell Nanoparticles

Abstract

Due to less interference in biological imaging, nanomaterials with second near-infrared (NIR-II) window (950-1700 nm) emission have received tremendous attention. However, no reports on NIR-II electrochemiluminescence (ECL) imaging exist because of the lack of high-efficiency NIR-II ECL luminophores. Herein, we designed and synthesized a NaYbF4@SiO2core-shell nanoparticle for the first time, which exhibited a record-high ECL efficiency of 384% relative to the benchmark Ru(bpy)32+. The NaYbF4core ensured a maximum emission peak at 983 nm; the synergistic effect of enrichment and catalysis provided by an external mesoporous shell significantly enhanced the ECL signal of particles and improved the stability. Moreover, the ECL generation mechanism was identified through density functional theory calculations. This work has broken through the wavelength bottleneck of NIR-ECL probes in the water-phase and can guide the design of subsequent NIR-II ECL emitters.