Photonic crystal (PC) nanocavities based on silicon nitride membranes are studied as tools for the manipulation of spontaneous emission in the wavelength range between 550 nm and 800 nm. We observe a strong modification of the fluorescence spectrum of dye molecules spin-cast on top of the PC, indicating an efficient coupling of the dye emission to the cavity modes. The cavity design is optimized with respect to the quality factor and values of nearly 1500 are achieved experimentally. Taking into account the small mode volume, which leads to a strong Purcell enhancement, these nanocavities enable the realization of efficient single photon sources in the visible region of the spectrum. Furthermore, their fabrication is fully compatible with existing CMOS technology, making an integration into more complex optoelectronic devices feasible.
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http://dx.doi.org/10.1364/oe.15.017231 | DOI Listing |
Molecules
January 2025
School of Materials and Environment, Beijing Institute of Technology, Zhuhai 519088, China.
This study employs quantum chemical computational methods to predict the spectroscopic properties of fluorescent probes 2,6-bis(2-benzimidazolyl)pyridine (BBP) and ()-3-(2-(1-benzo[]imidazol-2-yl)vinyl)-9-(2-(2-methoxyethoxy)ethyl)-9-carbazole (BIMC). Using time-dependent density functional theory (TDDFT), we successfully predicted the fluorescence emission wavelengths of BBP under various protonation states, achieving an average deviation of 6.0% from experimental excitation energies.
View Article and Find Full Text PDFEnviron Res
January 2025
China Academy of Safety Science and Technology, Beijing 100012, China. Electronic address:
Spontaneous coal fires are a significant source of greenhouse gas emissions, contributing to global warming. However, the lack of reliable estimation methods and research has obscured the full environmental impact of these emissions. This paper presents a novel quantification method for fugitive carbon emissions from spontaneous coal combustion.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China.
Perovskite quantum dots (QDs) are high-efficiency optoelectronic materials attracting great interest, but further improvement in the luminescence efficiency is crucial for their application. In this work, we enhance both the spontaneous emission rate and the photoluminescence (PL) intensity of CsPbBr QDs by coupling them to a high quality () factor SiO microdisk cavity. Compared to conventional metal plasmonic cavities, the dielectric cavity structure suppresses the effects of quenching and energy transfer, which could introduce complex fluctuations and nonradiative decays.
View Article and Find Full Text PDFAnal Chem
January 2025
Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
The near-infrared electrochemiluminescence (NIR-ECL) technique has received special attention in cell imaging and biomedical analysis due to its deep tissue penetration, low background interference, and high sensitivity. Although cyanine-based dyes are promising NIR-ECL luminophores, limited ECL efficiency and the need for exogenous coreactants have prevented their widespread application. In this work, poly[9,9-bis(3'-(-dimethylamino)propyl)-2,7-fluorene]--2,7-(9,9-dioctylfluorene)] (PFN) was innovatively developed to significantly invigorate the NIR-ECL performance of heptamethine cyanine dye IR 783 by the resonance energy transfer (RET) strategy.
View Article and Find Full Text PDFACS Appl Bio Mater
January 2025
Department of Chemistry, Indian Institute of Technology Palakkad, Palakkad, Kerala 678 623, India.
The aggregation of proteins, peptides and amino acids has been a keen subject of interest owing to their implications in metabolic disorders. In this work, we investigated the self-aggregation of the unmodified aromatic amino acid l-tryptophan (Trp) into unusual spherical microstructures. Using fluorescence spectroscopy and field emission scanning electron microscopy (FE-SEM), we detail the time-dependent transformation of monomeric tryptophan into spherical aggregates with distinct fluorescence characteristics (λ = 345 nm, λ = 430 nm) compared to the monomer.
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