Integrating temporal and spatial control of electronic transitions for bright multiphoton upconversion

Abstract

The applications of lanthanide-doped upconversion nanomaterials are limited by unsatisfactory brightness currently. Herein, a general strategy is proposed for boosting the upconversion efficiency in Er 3+ ions, based on combined use of a core−shell nanostructured host and an integrated optical waveguide circuit excitation platform. A NaErF 4 @NaYF 4 core−shell nanoparticle is constructed to host the upconversion process for minimizing non-radiative dissipation of excitation energy by surface quenchers. Furthermore, an integrated optical microring resonator is designed to promote absorption of excitation light by the nanoparticles, which alleviates quenching of excited states due to cross-relaxation and phonon-assisted energy transfer. As a result, multiphoton upconversion emission with a large anti-Stokes shift (greater than 1150 nm) and a high energy conversion efficiency (over 5.0%) is achieved under excitation at 1550 nm. These advances in controlling photon upconversion offer exciting opportunities for important photonics applications.

Manipulation of up-conversion emission in NaYF4core@shell nanoparticles doped by Er3+, Tm3+, or Yb3+ions by excitation wavelength—three ions—plenty of possibilities

“…25,40,41,44 Only Tm 3+ ions can be used as sensitizers for this radiation, due to 3 H 6 → 3 H 5 GSA, followed by another ESA process. 37,41 Single-doped NaYF 4 :2%Tm 3+ @NaYF 4 NPs showed UC emission at 700 ( 3 F 3 → 3 H 6 ) and 804 nm ( 3 H 4 → 3 H 6 ; Fig. 6a).…”

Thermal Enhancement of Upconversion by Negative Lattice Expansion in Orthorhombic Yb2W3O12

“…We also investigated upconversion in Er 2 W 3 O 12 crystals by excitation at 1532 nm . The high Er 3+ content in this host ensures energy transfer upconversion due to energy hopping through the erbium sublattice . As a consequence, 1532 nm‐excited upconversion in the Er 2 W 3 O 12 crystals was thermally enhanced (Figure S6, Supporting Information).…”

Lanthanide-Doped Upconversion Nanoparticles for Super-Resolution Microscopy

“…This actually poses a challenge for tuning the luminescence properties of UCNPs, which are not as flexible as that of organic dyes and quantum dots. On the other hand, the stimulated emission cross-section of UCNPs is quite small because of the parity-forbidden nature (Sun et al, 2019 ), which makes it difficult to achieve stimulated emission for STED microscopy. In this perspective article, we firstly summarized the recent advances in UCNPs-based super-resolution microscopy and then discussed the future directions in aspects of UCNPs design and cellular biological applications.…”