Versatile Spectral and Lifetime Multiplexing Nanoplatform with Excitation Orthogonalized Upconversion Luminescence.

Optical encoding together with color multiplexing benefits on-site detection, and enriching the components with narrow emissions from lanthanide could greatly increase the coding density. Here, we show a typical example to combine emission color and lifetime that are simultaneously integrated in a single lanthanide nanoparticle. With the multicompartment core/shell structure, the nanoparticles can activate different emitting pathways under varied excitation. This enables the nanoparticles to generate versatile excitation orthogonalized upconversion luminescence in both emission colors and lifetimes. As a typical example, green emission of Er and blue emission of Tm can be triggered with 808 and 980 nm lasers, respectively. Moreover, with incorporation of Tb, not only is emission from Tb introduced but also the lifetime difference of 0.13 ms (Er) and 3.6 ms (Tb) is yielded for the green emission, respectively. Multiplexed fingerprint imaging and time-gated luminescence imaging were achieved in wavelength and lifetime dimensions. The spectral and lifetime encoding ability from lanthanide luminescence greatly broadens the scope of luminescent materials for optical multiplexing studies.