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Highly selective and sensitive detection of catecholamines using NaLuGdF4:Yb3+/Er3+ upconversion nanoparticles decorated with metal ions
摘要： We developed a novel optical sensor for sensitive and selective detection of catecholamines based on upconversion nanoparticles (UCNPs) decorated with different metal ions (UCNP-Men+). 1,2-ethanedithiol was chosen as a surface additive to synthesize the NaLuGdF4:Yb3+/Er3+ UCNPs by one-step at 200 °C. The as-prepared UCNPs exhibited a strong emission under the continuous excitation at 980 nm. It was found that catecholamines could be more effectively detected in the presence of UCNP-Fe3+, whereas, dopamine and epinephrine were detected selectively using UCNP-Li+ and UCNP-Cu2+ sensors, respectively. Under the optimum conditions, the limit of detections (LODs) for catecholamines, dopamine, and epinephrine are 2.8, 2.5, and 2.4 nM, respectively, with good linearity in the range of 5–320 nM for total catecholamines and 5–30 nM for dopamine and epinephrine. The developed method has been successfully applied to detect dopamine and epinephrine in human urine samples with good accuracy and satisfactory recovery.
关键词： Upconversion nanoparticles,Human urine,Metal ion decorated,Catecholamines,1,2-ethanedithiol
更新于2025-09-23 15:23:52
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Two novel fluorescent probes based on phenothiazine: synthesis and “naked-eye” colorimetric recognition of Hg2+
摘要： Two novel colorimetric and fluorescent probes 2-(1,3-dithiolanes)-10-ethyl phenothiazine (PHE–Ed) and 2-(1,3-dithianes)-10-ethyl phenothiazine (PHE–Pd) based on phenothiazine were successfully synthesized, and their structure was confirmed by NMR and high resolution mass spectra. Fluorescence investigations revealed that the synthesized probes could be used for the selective detection of Hg2+, which was accompanied with an obvious color change from colorless to light yellow. The applicable ability of the two probes was investigated by a series of competitive experiments, solid colorimetric experiments, and applied experiments, which proved that these probes showed high sensitivity and great potential to detect Hg2+ in environmental analysis systems. Furthermore, the detection mechanism of the probes was investigated by FT-IR spectra and NMR spectra, and the results indicated that the detection of Hg2+ was accomplished through the Hg2+-promoted deprotection of thioacetal.
关键词： Phenothiazine,ICT fluorophore,1,3-propanedithiol,Naked-eye,1,2-ethanedithiol
更新于2025-09-23 15:22:29
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Optimizing Solid-State Ligand Exchange for Colloidal Quantum Dot Optoelectronics: How Much Is Enough?
摘要： Progress in chalcogenide and perovskite CQD optoelectronics has relied in significant part on solid-state ligand exchanges (SSEs): the replacement of initial insulating ligands with shorter conducting linkers on CQD surfaces. Herein we develop a mechanistic model of SSE employing 3-mercaptopropionic acid (MPA) and 1,2-ethanedithiol (EDT) as the linkers. The model suggests that optimal linker concentrations lead to efficient exchange resulting in ca. 200 – 300 exchanged ligands per CQD, a 50% thickness reduction of the initial film, decreased interdot spacing, a 15 nm red-shift in the excitonic absorption peak and a 10x reduction in carrier lifetime. It is a combined effect of these physico-chemical changes that have traditionally made 1% MPA and 10-2% EDT (v:v) the concentrations of choice for efficient CQD optoelectronics.
关键词： Colloidal quantum dots,1,2-ethanedithiol,solid-state ligand exchange,3-mercaptopropionic acid,solar cells
更新于2025-09-23 15:19:57
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Impact of 1,2-ethanedithiol treatment on luminescence and charge-transport characteristics in colloidal quantum-dot LEDs
摘要： We report on a substantial increase in luminance and luminous ef?ciency of green-light emitting devices (LEDs) that use colloidal CdSe@ZnS quantum dots (QDs) as a light-emitting material in response to treatment with 1,2-ethanedithiol (EDT). The maximum luminance increased from 1146 to 8075 cd m?2, and luminous yield from 0.15 to 1.41 cd A?1 as a result of treating an incomplete device with drops of EDT right after spin-coating QDs onto a ZnO-nanoparticle layer. Based on systematic studies on substrate-dependent change in photoluminescence, and current-voltage and luminance–voltage characteristics, we propose that passivation of intra-gap defect states and relative shifts of energy levels relevant to the operation of QD LEDs are two main results of EDT treatment. In particular, we argue that energy-level shift without emission-color change can be attributed to surface-dipole effects.
关键词： quantum-dot LED,1,2-ethanedithiol (EDT) treatment,defect-state passivation,surface-dipole effect,green-emitting CdSe@ZnS
更新于2025-09-19 17:13:59
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Effects of 1,2-ethanedithiol concentration on performance improvement of quantum-dot LEDs
摘要： We report systematic e?ciency variations of green-emitting CdSe@ZnS quantum-dot (QD) LEDs (QLEDs) in response to in situ treatments with 1,2-ethanedithiol (EDT) solutions at various concentrations. The main e?ect of in situ EDT treatment on a QD layer spin-coated onto a ZnO layer was vacuum-level shift due to dipole moments on the surface of the QD layer and at the interface between QD and ZnO layers. Competing contributions of these dipole moments were responsible for changes in energy level con?gurations and, accordingly, electron and hole barriers that resulted in discrepancies in electron- and hole-current variations. QLED e?ciency was best when treated with an EDT solution of 4 mM, attributable to the largest increase in the hole- to electron current ratio. The maximum luminous yield of the 4 mM EDT-treated QLED was 5.43 cd A(cid:1)1, which is 10 times higher than that of an untreated device. Furthermore, the luminous yield of this treated device remained as high as 2.56 cd A(cid:1)1 at a luminance of 500 cd m(cid:1)2.
关键词： efficiency improvement,vacuum-level shift,dipole moments,quantum-dot LEDs,1,2-ethanedithiol
更新于2025-09-16 10:30:52