Recent Development in Sensitizers for Lanthanide-Doped Upconversion Luminescence

Abstract

The attractive features of lanthanide-doped upconversion luminescence (UCL), such as high photostability, nonphotobleaching or photoblinking, and large anti-Stokes shift, have shown great potentials in life science, information technology, and energy materials. Therefore, UCL modulation is highly demanded toward expected emission wavelength, lifetime, and relative intensity in order to satisfy stringent requirements raised from a wide variety of areas. Unfortunately, the majority of efforts have been devoted to either simple codoping of multiple activators or variation of hosts, while very little attention has been paid to the critical role that sensitizers have been playing. In fact, different sensitizers possess different excitation wavelengths and different energy transfer pathways (to different activators), which will lead to different UCL features. Thus, rational design of sensitizers shall provide extra opportunities for UCL tuning, particularly from the excitation side. In this review, we specifically focus on advances in sensitizers, including the current status, working mechanisms, design principles, as well as future challenges and endeavor directions.

Orthogonal Trichromatic Upconversion with High Color Purity in Core‐Shell Nanoparticles for a Full‐Color Display

“…Upconversion nanoparticles (UCNPs) doped with lanthanide ions that feature ladder‐like energy levels can produce multiple emissions span from ultraviolet to near‐infrared, making them ideal candidates for full‐color tuing [20–25] . Intriguingly, the significant development of core–shell structural design over the past few years provides an effective platform for color modulation in a single upconversion nanoparticle by tailoring the emission profiles of different lanthanide centers [26–33] . Despite the enticing prospect, the current development of full‐color upconversion nanoparticles is hindered by the harsh need of excitation setup, such as complex three‐channel photo upconversion and complicated pulse width modulation [34–37] .…”

Multi-wavelength excitable mid-infrared luminescence and energy transfer in core–shell nanoparticles for nanophotonics

“…[33][34][35][36][37] Also, the excitation wavelengths are still limited to specific wavelengths, e.g., 980 nm. Recently, Er 3+ has been shown to be an effective sensitizer to activate lanthanide ions for upconversion luminescence in nanocrystals, 38,39 and the excitation wavelength was extended to the 1530-1550 nm range. Nevertheless, it should be noted that previous studies on lanthanide-doped nanoparticles were almost focused on the visible and near-infrared emission properties, and little attention was paid to the MIR spectral region.…”

Amplifying Photoluminescence of Lanthanide-Doped Nanoparticles by Iridium Phosphonate Complex

“…Lanthanide-doped nanoparticles hold great potential in diverse fields, including anticounterfeiting, bioimaging, and lasing, due to their unique luminescent features, such as tunable luminescence, a large Stokes/anti-Stokes shift, and excellent photostability. − Unfortunately, the unsatisfactory luminescent intensity, together with the limited excitation wavelength, arising from the intrinsically weak and narrow absorbance of lanthanide ions restrains the further development of lanthanide-doped nanoparticles. In consequence, different strategies, including fabrication of core–shell structures, doping optimization, and antenna sensitization, have been developed to enhance and tune the luminescence of lanthanide-doped nanoparticles. − Among these strategies, antenna sensitization, which utilizes the strong and tunable absorption of antenna materials, exhibits superior facileness and high efficiency for enhancing lanthanide luminescence and thus is considered as one of most promising methods. , …”

“…18−23 Among these strategies, antenna sensitization, which utilizes the strong and tunable absorption of antenna materials, exhibits superior facileness and high efficiency for enhancing lanthanide luminescence and thus is considered as one of most promising methods. 22,23 Organic dyes, which can anchor on the surface of nanoparticles, are the most commonly used antenna materials for amplifying the luminescence of lanthanide-doped nanoparticles. 24−26 For example, the downshifting, upconversion, and downconversion luminescence of lanthanide-doped nanoparticles can all be dramatically enhanced by organic dye sensitization.…”