Dense assembly of Gd2O3:0.05X3+ (X = Eu, Tb) nanorods into nanoscaled thin-films and their photoluminescence properties

Nanomembrane-assembled nanophotonics and optoelectronics: from materials to applications

Nanophotonics and optoelectronics are the keys to the information transmission technology field. The performance of the devices crucially depends on the light-matter interaction, and it is found that three-dimensional (3D) structures may be associated with strong light field regulation for advantageous application. Recently, 3D assembly of flexible nanomembranes has attracted increasing attention in optical field, and novel optoelectronic device applications have been demonstrated with fantastic 3D design. In this review, we first introduce the fabrication of various materials in the form of nanomembranes. On the basis of the deformability of nanomembranes, 3D structures can be built by patterning and release steps. Specifically, assembly methods to build 3D nanomembrane are summarized as rolling, folding, buckling and pick-place methods. Incorporating functional materials and constructing fine structures are two important development directions in 3D nanophotonics and optoelectronics, and we settle previous researches on these two aspects. The extraordinary performance and applicability of 3D devices show the potential of nanomembrane assembly for future optoelectronic applications in multiple areas.

Y2O3: Eu3+/PMMA hybrid film as a converter for enhanced harvesting of broadband solar-blind UV light

At present, the most common materials for solar-blind UV light detectors are wide band-gap semiconductors, which generally have high requirements and complex methods for preparation. Ordinary semiconductor materials such as silicon, TiO₂, and Cu₂O were industrialized, but they were excluded for direct harvest of solar-blind UV light due to their inability to absorb solar-blind light photons. Here, inorganic-organic hybrid film of Y₂O₃:Eu³⁺/PMMA was used as a spectral converter to realize the detection of broadband solar-blind UV light by ordinary semiconductor, converting broadband solar-blind UV luminescence to visible luminescence based on down-conversion process, after which the visible luminescence was detected by the Si photo-resister. The results show that hybrid film based on rare earth luminescence materials is particularly valuable for broadband solar-blind UV detection.

Development and characterization of a scintillating cell imaging dish for radioluminescence microscopy

Radioluminescence microscopy is an emerging modality that can be used to image radionuclide probes with micron-scale resolution. This technique is particularly useful as a way to probe the metabolic behavior of single cells and to screen and characterize radiopharmaceuticals, but the quality of the images is critically dependent on the scintillator material used to image the cells. In this paper, we detail the development of a microscopy dish made of a thin-film scintillating material, Lu2O3:Eu, that could be used as the blueprint for a future consumable product. After developing a simple quality control method based on long-lived alpha and beta sources, we characterize the radioluminescence properties of various thin-film scintillator samples. We find consistent performance for most samples, but also identify a few samples that do not meet the specifications, thus stressing the need for routine quality control prior to biological experiments. In addition, we test and quantify the transparency of the material, and demonstrate that transparency correlates with thickness. Finally, we evaluate the biocompatibility of the material and show that the microscopy dish can produce radioluminescent images of live single cells.

Bifunctional Luminomagnetic Rare-Earth Nanorods for High-Contrast Bioimaging Nanoprobes

Nanoparticles exhibiting both magnetic and luminescent properties are need of the hour for many biological applications. A single compound exhibiting this combination of properties is uncommon. Herein, we report a strategy to synthesize a bifunctional luminomagnetic Gd2-xEuxO3 (x = 0.05 to 0.5) nanorod, with a diameter of ~20 nm and length in ~0.6 μm, using hydrothermal method. Gd2O3:Eu(3+) nanorods have been characterized by studying its structural, optical and magnetic properties. The advantage offered by photoluminescent imaging with Gd2O3:Eu(3+) nanorods is that this ultrafine nanorod material exhibits hypersensitive intense red emission (610 nm) with good brightness (quantum yield more than 90%), which is an essential parameter for high-contrast bioimaging, especially for overcoming auto fluorescent background. The utility of luminomagnetic nanorods for biological applications in high-contrast cell imaging capability and cell toxicity to image two human breast cancer cell lines T47D and MDA-MB-231 are also evaluated. Additionally, to understand the significance of shape of the nanostructure, the photoluminescence and paramagnetic characteristic of Gd2O3:Eu(3+) nanorods were compared with the spherical nanoparticles of Gd2O3:Eu(3+).

Bright Lu2 O3 :Eu Thin-Film Scintillators for High-Resolution Radioluminescence Microscopy

The performance of a new thin-film Lu₂ O₃ :Eu scintillator for single-cell radionuclide imaging is investigated. Imaging the metabolic properties of heterogeneous cell populations in real time is an important challenge with clinical implications. An innovative technique called radioluminescence microscopy has been developed to quantitatively and sensitively measure radionuclide uptake in single cells. The most important component of this technique is the scintillator, which converts the energy released during radioactive decay into luminescent signals. The sensitivity and spatial resolution of the imaging system depend critically on the characteristics of the scintillator, that is, the material used and its geometrical configuration. Scintillators fabricated using conventional methods are relatively thick and therefore do not provide optimal spatial resolution. A thin-film Lu₂ O₃ :Eu scintillator is compared to a conventional 500 μm thick CdWO₄ scintillator for radioluminescence imaging. Despite its thinness, the unique scintillation properties of the Lu₂ O₃ :Eu scintillator allow us to capture single-positron decays with fourfold higher sensitivity, which is a significant achievement. The thin-film Lu₂ O₃ :Eu scintillators also yield radioluminescence images where individual cells appear smaller and better resolved on average than with the CdWO₄ scintillators. Coupled with the thin-film scintillator technology, radioluminescence microscopy can yield valuable and clinically relevant data on the metabolism of single cells.

Highly bright multicolour emission through energy migration in core/shell nanotubes

Multicolour photoluminescence was achieved in gadolinium-based core/shell nanotube structures via energy migration of Ce³⁺→Gd³⁺→Ln³⁺ and Ce³⁺→Ln³⁺ (Ln = Eu, Tb, Dy and Sm) in separated layers.

Low-temperature crystal growth of aluminium-doped zinc oxide nanoparticles in a melted viscous liquid of alkylammonium nitrates for fabrication of their transparent crystal films

Highly transparent AZO films have been successfully fabricated via crystal growth of AZO nanoparticles in a melted isopropylammonium nitrate medium.