Luminescence property tuning of Yb3+-Er3+ doped oxysulfide using multiple-band co-excitation

Lanthanide ions have abundant excited-state channels which result in a radiation relaxation process generally accompanied by a non-radiation relaxation process. However, non-radiation relaxation processes will consume the activation energy and reduce the luminescence efficiency of the phosphor. Two lasers with an excitation energy which matched the ground state absorption and excited state absorption of ions were used to excite the phosphors to avoid the non-radiation relaxation process. This approach can achieve the purpose of populating specific states of the lanthanide ions, and furthermore effectively tunes the luminescence intensity and color output of the sample. Results show that the red emission intensity of the sample is significantly improved and this is caused by populating the ⁴F_9/2 level under simultaneous 1510 nm and 980 nm excitation. Then when the 1510 nm and 808 nm co-operate to excite the sample, the green emission obtained increased sharply because the ²H_11/2/⁴S_3/2 states were efficiently populated. As a proof-of-concept experiment, this new approach has potential in the applications of solar cells.

The emission intensity of the sample excited by dual-wavelength (980 and 1510 nm) is 3.2 times than the sum of UCL emission under the two single wavelength excitation.

Controlled synthesis of lanthanide-doped Gd2O2S nanocrystals with novel excitation-dependent multicolor emissions

Developing multicolor-emitting materials has significant value in many research fields such as displays, bioimaging, and information storage. The widely adopted strategies to realize multicolor emission are tuning the material composition, phase, and size. Herein, the emission color was continuously controlled from yellow to pink by simply changing the excitation wavelength from 254 nm to 365 nm for Tb³⁺/Eu³⁺ co-doped Gd₂O₂S NCs. The Gd₂O₂S NCs with different morphologies, including nanoplate with various sizes and flower-like, were successfully prepared by seed-mediated, Na⁺/Y³⁺ co-doped, and S concentration-tuned methods. The results indicated that Na⁺ ions greatly promote the growth of Gd₂O₂S NCs and Y³⁺ ions have an impact on their shape. Moreover, the PL intensity of the 2%Eu-doped flower-like Na/Y:Gd₂O₂S (F-NYG) NCs decreased by about 24.7%, 6.8%, and 5.1% under 254 nm, 316 nm, and 348 nm excitation, respectively; this is due to less non-radiative relaxation paths above the excited state of Eu³⁺:⁵D₀ at longer excitation wavelength, which result in a decreased degree of the PL intensity reduction.

Understanding the remarkable luminescence enhancement via SiO2 coating on TiO2:Eu3+ nanofibers

Red luminescence is enhanced by coating an SiO₂ layer on TiO₂:Eu³⁺ nanofibers, and the luminescence enhancement mechanism is discussed.

Controlled synthesis and morphology dependent luminescence of Lu2O2S:Eu3+ phosphors

The dependence of Lu₂O₂S:Eu³⁺ luminescence performance on different morphologies has been explored and possible reasons are proposed.

A self-assembling lanthanide molecular nanoparticle for optical imaging

Chromophores that incorporate f-block elements have considerable potential for use in bioimaging applications because of their advantageous photophysical properties compared to organic dye, which are currently widely used. We are developing new classes of lanthanide-based self-assembling molecular nanoparticles as reporters for imaging and as multi-functional nanoprobes or nanosensors for use with biological samples. One class of these materials, which we call lanthanide "nano-drums", are homogeneous 4d-4f clusters approximately 25 to 30 Å in diameter. These are capable of emitting from the visible to near-infrared wavelengths. Here, we present the synthesis, crystal structure, photophysical properties and comparative cytotoxicity data for a 32 metal Eu-Cd nano-drum [Eu(8)Cd(24)L(12)(OAc)(48)] (1). We also explored the imaging capabilities of this nano-drum using epifluorescence, TIRF, and two-photon microscopy platforms.

A new tactic to achieve Y2O2S:Yb3+/Er3+ up-conversion luminescent hollow nanofibers

Y₂O₂S:Yb³⁺/Er³⁺ hollow nanofibers were synthesized via inheriting the morphology of electrospinning-derived precursors and exhibited excellent up-conversion luminescence properties.

A new route to fabricate LaOI:Yb3+/Er3+ nanostructures via inheriting the morphologies of the precursors

LaOI:Yb³⁺/Er³⁺ nanofibers and nanobelts have been successfully synthesized via inheriting the morphologies of the precursors and they exhibit excellent up-conversion luminescence properties.

Fabrication and photoluminescence properties of TiO2:Eu3+ microspheres with tunable structure from solid to core–shell

The structure of TiO₂:Eu³⁺ microspheres can be tuned from solid to core–shell only by changing the amount of ethanol. In addition, the PL intensity of Eu³⁺ ions is related to the structure of the microspheres.