Luminescence quantum yields (QYs) of gold nanoparticles including nanorods, nanobipyramids and nanospheres are measured elaborately at a single nanoparticle level with different excitation wavelengths. It is found that the QYs of the nanostructures are essentially dependent on the excitation wavelength. The QY is higher when the excitation wavelength is blue-detuned and close to the nanoparticles' surface plasmon resonance peak. A phenomenological model based on the plasmonic resonator concept is proposed to understand the experimental findings. The excitation wavelength dependent QY is attributed to the wavelength dependent coupling efficiency between the free electron oscillation and the intrinsic plasmon resonant radiative mode. These studies should contribute to the understanding of one-photon luminescence from metallic nanostructures and plasmonic surface enhanced spectroscopy.
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http://dx.doi.org/10.1039/c5nr07343j | DOI Listing |
Mikrochim Acta
January 2025
Guizhou Province, Qianzhi Mingguang Soaphorn Rice Processing Base, Zhijin County, Maochang Town, Bijie CityBijie City, 552103, China.
A smartphone-based non-invasive method was developed for salivary uric acid detection using Gleditsia Sinensis carbon dots (GS-CDs). The GS-CDs synthesized by the one-pot hydrothermal method emitted blue fluorescence at a maximum excitation wavelength of 350 nm and had good fluorescence stability in the presence of different ions, while showing selectivity to uric acid solution. The ability of uric acid (UA) to quench the fluorescent substances present in the GS-CDs, was confirmed through HPLC-FLD and LC-MS, FTIR and XPS.
View Article and Find Full Text PDFNatl Sci Rev
February 2025
Institute of Nanoscience and Applications, Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
Colloidal quantum dots (QDs) are solution-processable semiconductor nanocrystals with favorable optoelectronic characteristics, one of which is their multi-excitonic behavior that enables broadband polychromatic light generation and amplification from monodisperse QDs. However, the practicality of this has been limited by the difficulty in achieving spatial separation and patterning of different colors as well as the high pumping intensity required to excite the multi-excitonic states. Here, we have addressed these issues by integrating monodisperse QDs in multi-excitonic states into a specially designed cavity, in which the QDs exhibit an anisotropic polychromatic emission (APE) characteristic that allows for tuning the emission from green to red by shifting the observation direction from perpendicular to lateral.
View Article and Find Full Text PDFLuminescence
January 2025
Department of Physics, IMN, Universidad de La Laguna, San Cristobal de La Laguna, Santa Cruz de Tenerife, Spain.
Er-doped BaF single crystals were investigated with two primary aims: first, to probe the infrared emissions from the I level (around 1.0 μm) under 1500-nm excitation and, second, to use the crystal to enhance the efficiency of silicon-based solar cells through upconversion mechanism. Upon excitation at 1500 nm, the upconversion emission spectrum of the Er-doped BaF single crystals, recorded in the range of 480-1080 nm, exhibited two well-structured visible bands at 538 and 650 nm, along with a strong near infrared emission at 971 nm.
View Article and Find Full Text PDFRSC Adv
January 2025
Institute of Polymer and Dye Technology, Lodz University of Technology Stefanowskiego 16 Lodz 90537 Poland.
This study investigates the structure-property relationships of a series of phenylhydrazones bearing various electron-donating and electron-withdrawing substituents, such as methoxy, dimethylamino, morpholinyl, hydroxyl, chloro, bromo, and nitro groups. The compounds were synthesized, and their structures were characterized using single-crystal X-ray diffraction, powder X-ray diffraction, FTIR spectroscopy, NMR spectroscopy, and DSC. Three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy and UV-Vis spectroscopy were employed to elucidate the complex interplay between the molecular skeleton, substituents, and the resulting photophysical properties.
View Article and Find Full Text PDFFood Chem X
January 2025
Department of Food Technology and Nutrition, School of Agriculture, Lovely Professional University, Phagwara, 144411, India.
The study focused on converting tea bag waste into strong fluorescence carbon quantum dots (TBW-CQDs) for the detection of acrylamide in drinking water, antimicrobial activity, and photocatalytic degradation. The TBW-CQDs exhibited blue luminescence and maximum absorbance at 287 nm under UV light and distinctive fluorescence emission and excitation wavelengths at 425 nm and 287 nm, respectively. TBW-CQDs revealed a particle size of 8.
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