The paper reports for the first time the direct determination of silver ion (Ag(+)) using luminescent Carbon Quantum Dot hydrogels (CQDGs). Carbon Quantum Dots (CQDs) with different superficial moieties (passivate-CQDs with carboxylic groups, thiol-CQDs and amine-CQDs) were used to prepare hybrid gels using a low molecular weight hydrogelator (LMWG). The use of the gels results in considerable fluorescence enhancement and also markedly influences selectivity. The most selective CQDG system for Ag(+) ion detection proved to be those containing carboxylic groups onto their surface. The selectivity towards Ag(+) ions is possibly due to its flexible coordination sphere compared with other metal ions. This fluorescent sensing platform is based on the strong Ag-O interaction which can quench the photoluminescence of passivate-CQDs (p-CQDs) through charge transfer. The limit of detection (LOD) and quantification (LOQ) of the proposed method were 0.55 and 1.83µgmL(-1), respectively, being applied in river water samples.
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http://dx.doi.org/10.1016/j.talanta.2016.01.029 | DOI Listing |
ACS Cent Sci
January 2025
Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States.
In quantum information science and sensing, electron spins are often purified into a specific polarization through an optical-spin interface, a process known as optically detected magnetic resonance (ODMR). Diamond-NV centers and transition metals are both excellent platforms for these so-called color centers, while metal-free molecular analogues are also gaining popularity for their extended polarization lifetimes, milder environmental impacts, and reduced costs. In our earlier attempt at designing such organic high-spin π-diradicals, we proposed to spin-polarize by shelving triplet = ±1 populations as singlets.
View Article and Find Full Text PDFACS Omega
January 2025
Instituto de Física, Universidade Federal de Goiás, Goiânia, Goiás 74001-970, Brazil.
We investigate the energetic and structural properties of small lithium clusters doped with a carbon atom using a combination of computational methods, including density functional theory (DFT), diffusion quantum Monte Carlo (DMC), and the Hartree-Fock (HF) approximation. We calculate the lowest energy structures, total ground-state energies, electron populations, binding energies, and dissociation energies as a function of cluster size. Our results show that carbon doping significantly enhances the stability of lithium clusters, increasing the magnitude of the binding energy by 0.
View Article and Find Full Text PDFChemphyschem
January 2025
Chinese Academy of Sciences, Institute of Coal Chemistry, 27 South Taoyuan Road, Taiyuan, Shanxi, P.R.China, 030001, Taiyuan, CHINA.
Electric double layer capacitors (EDLC) require large specific surface area to provide high power density. The generation of pores increases the electrochemical capacitance with more graphitic edge planes exposed to the electrolyte. Conventional theory believes this increasing in capacitance is owed to the increased specific surface area, but our work uncovers another mechanism.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, No. 308 Ningxia Road, Qingdao 266071 PR China. Electronic address:
Luminescent solar concentrators (LSCs) are large scale sunlight collector and can be used for building-integrated photovoltaics (BIPV). Achieving high-performance LSCs requires fluorophores with broad absorption, high quantum yield and a large Stokes shift. Nevertheless, conventional high-efficiency LSCs typically rely on heavy metal-based quantum dots as fluorophores.
View Article and Find Full Text PDFBiosens Bioelectron
January 2025
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain; Catalan Institution for Research and Advanced Studies (ICREA) Passeig de Lluís Companys, 23, Barcelona, 08010, Spain. Electronic address:
Quantum dots (QDs) are the smallest nanomaterials (2-10 nm), with unique optical and electronic properties. Thanks to these properties, QDs have been standing during the last years as signal tags for different applications, including bioimaging, fluorescent biosensors and electrochemical assays. In this review, we explore the current state-of-the art on these nanomaterials, differentiating them between semiconductor and carbon-based QDs.
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