Rare earth ion– and transition metal ion–doped inorganic luminescent nanocrystals: from fundamentals to biodetection

Doping Lanthanide Nanocrystals With Non-lanthanide Ions to Simultaneously Enhance Up- and Down-Conversion Luminescence

“…Modifying rare-earth nanocrystals with plasmonic noble metal can efficiently improve the luminescence by changing the surface electronic field, but also leads to relatively large and less stable structures that may be disassociated under certain conditions. Different from these two approaches, doping non-Ln ions to enhance the luminescence through modulating the local chemical environment of the emitting centers doesn't necessarily increase the particle size apart from forming more stable structures (Huang et al, 2019 ). Because of the interplay between the 4f electrons of Er 3+ and the crystal field of the host doped with non-Ln ions, the probability of radiative transitions within Er 3+ can hopefully be enhanced by relaxing the selection rules (Fischer et al, 2019 ).…”

Blue-LED-excitable NIR-II luminescent lanthanide-doped SrS nanoprobes for ratiometric thermal sensing

“…To circumvent the limitation of Ln 3+ -doped NIR-II luminescent NCs, it is of fundamental importance to introduce an antenna that can effectively harvest the excitation light and sensitize the NIR-II luminescence of Ln 3+ emitters [30][31][32][33]. In this regard, optical entities of allowed transitions with large absorption cross-sections such as Ce 3+ , Bi 3+ , ligand-to-metal charge transfer states, and the host absorption of semiconductors can be effective sensitizers for Ln 3+ luminescence [34][35][36][37]. The absorption of these species, however, is influenced significantly by the host matrix with respect to the site symmetry, the crystal field (CF) strength, and the covalency [38][39][40][41].…”

Eu3+-doped ratiometric optical thermometers: Experiment and Judd-Ofelt modelling

“…Luminescence thermal sensing was successfully demonstrated using different types of phosphors including quantum dots, fluorescent dyes and proteins, polymers, metal-organic frameworks, and rare earth or transition metal-doped materials [11][12][13][14][15][16][17][18]. Rare earth-doped phosphors have attracted the most attention as optical thermometers due to their unique spectroscopic properties: narrow emission and excitation lines, long lifetime, large Stokes shift, and diversity of emitting wavelength [19,20]. Luminescence thermometry utilizes temperature-induced changes in luminescence parameters such as intensity (single band or ratiometric), spectral line position, bandwidth, lifetime, and polarization [6,[21][22][23].…”