Enhanced near-infrared II luminescence in NaErF4 based core/shell nanocrystals via incorporating high Ce3+ ions concentration

Preparation of rare-earth doped NaYF4 luminescent nanoparticles by a high-energy ball milling process

“…The IR luminescence (1535 nm) results from a radiative decay of the intermediate 4 I 11/2 state ( 4 H 11/2 → 4 I 15/2 ), which can be effectively used for bioimaging in the second biotissue transparency window. 25,79,80 The PL decay kinetics of the most intense spectral bands at 408, 540, 653 and 1535 nm for the studied samples is well fitted by a single exponent:…”

“…Currently, NaYF 4 -based NPs co-doped with 20 mol% Yb 3+ /2 mol% Er 3+ and 20 mol% Yb 3+ /0.6 mol% Tm 3+ ions are well-explored and popular PL materials for various applications in photonics, both in up-and down-conversion excitation mechanisms. [20][21][22][23][24][25] The potential practical applications of these materials are primarily defined by the availability of versatile, reliable and eco-friendly approaches to their synthesis with controlled structural and morphological characteristics, since the size range and structure of NPs are of fundamental significance for realization of application-specific PL properties.…”

High-intensity first near-infrared emission through energy migration in multilayered upconversion nanoparticles

“…[1][2][3][4][5][6][7][8][9][10][11] In particular, UCNPs have unique advantages in biomedical imaging due to their large anti-Stokes shift, high sensitivity, low toxicity, and deep penetration. [12][13][14][15] In the past decades, visible light (400-700 nm) and first nearinfrared (NIR-I, 700-1000 nm) biomedical imaging was widely studied. 13,[16][17][18] However, most of the related reports were on the NIR-I excitation.…”

“…It is well known that water molecules have a strong resonance absorption peak at around 980 nm, while the 807 nm NIR-I emission of Tm 3+ and 1532 nm NIR-II excitation light can well stagger the resonance absorption peak of water molecules, which greatly reduces the thermal effect and avoids damage to biological tissues. 15,[26][27][28] Herein from the above statement, there is an urgent need to develop lanthanide-based UCNPs that emit high-intensity NIR-I emission under NIR-II excitation.…”