Filtration Shell Mediated Power Density Independent Orthogonal Excitations–Emissions Upconversion Luminescence

Abstract

Lanthanide doped core-multishell structured NaGdF4:Yb,Er@NaYF4:Yb@NaGdF4:Yb,Nd@NaYF4@NaGdF4:Yb,Tm@NaYF4 nanoparticles with power-density independent orthogonal excitations-emissions upconversion luminescence (UCL) were fabricated for the first time. The optical properties of these core-multishell structured nanoparticles were related to the absorption filtration effect of the NaGdF4:Yb,Tm layer. By tuning the thickness of the filtration layer, the nanoparticles can exhibit unique two independent groups of UCL: Tm(3+) prominent UV/blue (UV=ultraviolet) UCL under the excitation at 980 nm and Er(3+) prominent green/red UCL under the excitation at 796 nm. The filtration-shell mediated orthogonal excitations-emissions UCL are power-density independent. As a proof of concept, the core-multishell nanoparticles are used in multi-dimensional security design and imaging-guided combined photodynamic therapy and chemotherapy.

Integration of IR‐808 Sensitized Upconversion Nanostructure and MoS2 Nanosheet for 808 nm NIR Light Triggered Phototherapy and Bioimaging

“…Upconversion nanotechnology has drawn intensive attention for PDT application as it can convert near infrared (NIR) photons into higher‐energy visible lights, which are most commonly used for photosensitizer activation . It is known that NIR (650–1100 nm) photons have a higher transparency to biotissues in comparison with the lights of shorter wavelengths . The upconversion nanoparticles (UCNPs) emit upconverted lights under NIR irradiation, and the ensuing fluorescence resonance energy transfer to the carried photosensitizers transduces oxygen to reactive oxygen species (ROS) for cancer cell killing .…”

Cooperative and non-cooperative sensitization upconversion in lanthanide-doped LiYbF4 nanoparticles

“…This can be attributed to a synergic effect of the increased isolation of the core from its environment and the decreased Yb 3+ absorption arising from the increased shell thickness. 41,45 The integrated UCL intensity of the core/shell UCNPs with optimal shell thicknesses was enhanced by a factor of approximately 970, 7 and 6 for Er 3+ , Ho 3+ and Tm 3+ , respectively, in comparison with their coreonly counterparts (Fig. 2b-d) (Table S2 †).…”

Photon Upconversion Kinetic Nanosystems and Their Optical Response

“…In cascade sensitization UCNPs, efficient upconversion luminescence can be achieved by light irradiation at both 980 nm and 808 nm . By combining direct sensitization upconversion and cascade sensitization upconversion in core‐shell architectures, an orthogonal upconversion emission can be achieved in response to two distinct NIR excitation wavelengths . Such UCNPs offer new opportunities for developing advanced drug delivery systems that are capable of sequentially delivering bioimaging and sensing, and therapeutic modalities.…”