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Quantum key distribution (QKD) enables the transmission of information that is secure against general attacks by eavesdroppers. The use of on-demand quantum light sources in QKD protocols is expected to help improve security and maximum tolerable loss. Semiconductor quantum dots (QDs) are a promising building block for quantum communication applications because of the deterministic emission of single photons with high brightness and low multiphoton contribution. Here we report on the first intercity QKD experiment using a bright deterministic single photon source. A BB84 protocol based on polarisation encoding is realised using the high-rate single photons in the telecommunication C-band emitted from a semiconductor QD embedded in a circular Bragg grating structure. Utilising the 79 km long link with 25.49 dB loss (equivalent to 130 km for the direct-connected optical fibre) between the German cities of Hannover and Braunschweig, a record-high secret key bits per pulse of 4.8 × 10 with an average quantum bit error ratio of ~ 0.65% are demonstrated. An asymptotic maximum tolerable loss of 28.11 dB is found, corresponding to a length of 144 km of standard telecommunication fibre. Deterministic semiconductor sources therefore challenge state-of-the-art QKD protocols and have the potential to excel in measurement device independent protocols and quantum repeater applications.
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http://dx.doi.org/10.1038/s41377-024-01488-0 | DOI Listing |
Discov Nano
September 2025
Department of Rehabilitation Medicine, Rehabilitation Medical Center, Key Laboratory of Rehabilitation Medicine in Sichuan Province, West China Hospital, Sichuan University, Chengdu, 610041, People's Republic of China.
Immunoelectron Microscopy (IEM) is a technique that combines specific immunolabeling with high-resolution electron microscopic imaging to achieve precise spatial localization of biomolecules at the subcellular scale (< 10 nm) by using high-electron-density markers such as colloidal gold and quantum dots. As a core tool for analyzing the distribution of proteins, organelle interactions, and localization of disease pathology markers, it has irreplaceable value, especially in synapse research, pathogen-host interaction mechanism, and tumor microenvironment analysis. According to the differences in labeling sequence and sample processing, the IEM technology system can be divided into two categories: the first is pre-embedding labeling, which optimizes the labeling efficiency through the pre-exposure of antigenic epitopes and is especially suitable for the detection of low-abundance and sensitive antigens; the second is post-embedding labeling, which relies on the low-temperature resin embedding (e.
View Article and Find Full Text PDFAnal Bioanal Chem
September 2025
Hebei Key Laboratory of Public Health Safety, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Public Health, College of Chemistry and Materials Science, Hebei University, Baoding, 071002, China.
This work presents the development of a highly sensitive, selective, and efficient aptamer-based fluorescent sensor for detecting cortisol in human urine. Carbon quantum dots-nucleic acid aptamer (CQDs-Apt) synthesized with excellent photoluminescent properties and stability, were selected as the fluorescent probe. In the presence of MoS-NSs, CQDs-Apt adsorbed onto the surface of MoS-NSs via electrostatic and π-π interactions, leading to strong and rapid fluorescence quenching due to static quenching mechanism between them.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, London WC1H 0AJ, U.K.
The exceptional performance of ceria (CeO) in catalysis and energy conversion is fundamentally governed by its defect chemistry, particularly oxygen vacancies. The formation of each oxygen vacancy (V) is assumed to be compensated by two localized electrons on cations (Ce). Here, we show by combining theory with experiment that while this 1 V: 2Ce ratio accounts for the global charge compensation, it does not apply at the local scale, particularly in nanoparticles.
View Article and Find Full Text PDFJ Phys Chem Lett
September 2025
State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300401, P. R. China.
Quantum dots (QDs) converted to micro light-emitting diodes (LEDs) have emerged as a promising technology for next-generation display devices. However, their commercial application has been hindered by the susceptibility of QDs to photodegradation when directly exposed to an open environment. Here, we develop functional ligand zinc bis[2-(methacryloyloxy)ethyl] phosphate (Zn(BMEP)) to passivate QD surface anions through a phosphine-mediated surface reaction.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2025
College of Smart Materials and Future Energy, Fudan University, Songhu Road 2005, Shanghai, 200438, P.R. China.
Solar-driven photocatalytic oxygen reduction reaction using covalent organic frameworks (COFs) offers a promising approach for sustainable hydrogen peroxide (HO) production. Despite their advantages, the reported COFs-based photocatalysts suffer insufficient photocatalytic HO efficiency due to the mismatched electron-proton dynamics. Herein, we report three one-dimensional (1D) COF photocatalysts for efficient HO production via the hydrogen radical (H•) mediated concerted electron-proton transfer (CEPT) process.
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