The second near-infrared window (NIR-II, 1000–2000 nm) offers an ideal window for multi-channel photoluminescence lifetime imaging (mPLI) due to its excellent tissue penetration depth and minimal scattering. However, the inevitable spectral crosstalk caused by the widespread and overlapping emissions of traditional luminescent materials (such as organic dyes and quantum dots) limits the scalability of the mPLI channels. In this project, we developed a series of Ln 3+-doped (Ln = Nd, Er, Tm, or Ho) layered nanoparticles (Ln-SNPs) that achieved efficient multi-wavelength near-infrared-II luminescence. These nanoparticles can also be further engineered into concentration-mediated Yb 3+ energy relay nanoparticles, enabling precise tuning of the luminescence lifetime within the 1060–2050 nm range, thereby expanding the near-infrared-II imaging channels in mPLI. Notably, the engineered Tm-SNP exhibits an optimized downshifted emission at approximately 1850 nm (near-infrared-IIc sub-window), with a distinguishable luminescence lifetime span of up to three orders of magnitude at similar emission intensities. This advancement provides a powerful toolkit for multi-dimensional information encryption and multiplexed biological imaging applications. This study was published in Advanced Materials under the title "Yb3+ Energy Relay in Stratified Lanthanide Nanoparticles Enables Multidimensional NIR-II Lifetime Imaging".
References: DOI: 10.1002/adma.202519832