Deep-Learning-Assisted Discriminative Detection of Vitamin B and Vitamin B by Fluorescent MoSe Quantum Dots.

A facile and environmentally mindful approach for the synthesis of MoSe QDs was developed via the hydrothermal method from bulk MoSe. In this, the exfoliation of MoSe was enhanced with the aid of an intercalation agent (KOH), which could reduce the exfoliation time and increase the exfoliation efficiency to form MoSe QDs. We found that MoSe QDs display blue emission that is suitable for different applications.

A facile strategy of using MoS quantum dots for fluorescence-based targeted detection of nitrobenzene.

We present a simple approach for producing photoluminescent MoS quantum dots (QDs) using commercial MoS powder as a precursor along with NaOH and isopropanol. The synthesis method is particularly easy and environmentally friendly. The successful intercalation of Na ions into MoS layers and subsequent oxidative cutting reaction leads to the formation of luminescent MoS QDs.

pH-sensitive response of a highly photoluminescent MoS nanohybrid material and its application in the nonenzymatic detection of HO.

The mechanism behind the variation in the photoluminescence (PL) of a MoS nanohybrid material with pH was investigated. Highly fluorescent MoS quantum dots dispersed across MoS nanosheets (MoS QDNS) were synthesized by a hydrothermal route in the presence of NaOH. Upon reducing the pH from 13 to 6.

MoS nanohybrid as a fluorescence sensor for highly selective detection of dopamine.

Fluorescence sensors for biologically active molecules are catching attention due to their good performance and simplicity. Herein, we report a fluorescence sensor for the selective and sensitive detection of dopamine (DA) in aqueous samples. MoS2 nanohybrid material composed of MoS2 quantum dots dispersed over MoS2 nanosheets (MoS2 QDNS) in alkaline medium was employed as the fluorescent probe.

Understanding the Photoluminescence Mechanism of Nitrogen-Doped Carbon Dots by Selective Interaction with Copper Ions.

Doped fluorescent carbon dots (CDs) have drawn widespread attention because of their diverse applications and attractive properties. The present report focusses on the origin of photoluminescence in nitrogen-doped CDs (NCDs), which is unraveled by the interaction with Cu(2+) ions. Detailed spectroscopic and microscopic studies reveal that the broad steady-state photoluminescence emission of the NCDs originates from the direct recombination of excitons (high energy) and the involvement of defect states (low energy).

An ascorbic acid sensor based on cadmium sulphide quantum dots.

We present a Förster resonance energy transfer (FRET)-based fluorescence detection of vitamin C [ascorbic acid (AA)] using cadmium sulphide quantum dots (CdS QDs) and diphenylcarbazide (DPC). Initially, DPC was converted to diphenylcarbadiazone (DPCD) in the presence of CdS QDs to form QD-DPCD. This enabled excited-state energy transfer from the QDs to DPCD, which led to the fluorescence quenching of QDs.

In situ Raman spectroscopy of surfaces modified by ion soft landing.

The design and characterization of a system for in situ Raman analysis of surfaces prepared by ion soft landing (SL) is described. The performance of the new high vacuum compatible, low cost, surface analysis capability is demonstrated with surface enhanced Raman spectroscopy (SERS) of surfaces prepared by soft landing of ions of crystal violet, Rhodamine 6G, methyl orange and copper phthalocyanine. Complementary in situ mass spectrometric information is recorded for the same surfaces using a previously implemented secondary ion mass spectrometer (SIMS).

Reactions of organic ions at ambient surfaces in a solvent-free environment.

Solvent-free ion/surface chemistry is studied at atmospheric pressure, specifically pyrylium cations, are reacted at ambient surfaces with organic amines to generate pyridinium ions. The dry reagent ions were generated by electrospraying a solution of the organic salt and passing the resulting electrosprayed droplets pneumatically through a heated metal drying tube. The dry ions were then passed through an electric field in air to separate the cations from anions and direct the cations onto a gold substrate coated with an amine.

Vibrational spectroscopy and mass spectrometry for characterization of soft landed polyatomic molecules.

We report implementation of two powerful characterization tools, in situ secondary ion mass spectrometry (SIMS) and ex situ surface enhanced Raman spectroscopy (SERS), in analyzing surfaces modified by ion soft landing (SL). Cations derived from Rhodamine 6G are soft landed onto Raman-active silver colloidal substrates and detected using SERS. Alternatively and more conveniently, high-quality SERS data are obtained by spin coating a silver colloidal solution over the modified surface once SL is complete.

Gold nanoparticle superlattices as functional solids for concomitant conductivity and SERS tuning.

Mercaptosuccinic acid protected gold nanoparticles (Au@MSA) self assemble to form superlattice (SL) crystals at the air-water interface. These have been used for gas adsorption. The current-voltage (I-V) characteristics of the SL film with embedded SL crystals, obtained by four probe measurements, show Ohmic conduction.

In situ SIMS analysis and reactions of surfaces prepared by soft landing of mass-selected cations and anions using an ion trap mass spectrometer.

Mass-selected polyatomic cations and anions, produced by electrosonic spray ionization (ESSI), were deposited onto polycrystalline Au or fluorinated self-assembled monolayer (FSAM) surfaces by soft landing (SL), using a rectilinear ion trap (RIT) mass spectrometer. Protonated and deprotonated molecules, as well as intact cations and anions generated from such molecules as peptides, inorganic catalysts, and fluorescent dyes, were soft-landed onto the surfaces. Analysis of the modified surfaces was performed in situ by Cs(+) secondary ion mass spectrometry (SIMS) using the same RIT mass analyzer to characterize the sputtered ions as that used to mass select the primary ions for SL.