Wide range tuning of the size and emission color of             CH3NH3PbBr3 quantum dots by surface           ligands

Colour-tunable N,P-MoOx QDs with dual-signal output have been used for achieving a multifunctional probe for the determination of a wide range of pH changes (2–9) and environmental sensing.

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Armor-Like Passivated CsPbBr3 Quantum Dots: Boosted Stability with Hand-in-Hand Ligands and Enhanced Performance of Nuclear Battery

Journal of Materials Chemistry A ◽

10.1039/d0ta12365j ◽

2021 ◽

Author(s):

Haibo Zeng ◽

Dandan Yang ◽

Zhiheng Xu ◽

Chunhui Gong ◽

Xiaoming Li ◽

...

Keyword(s):

Quantum Dots ◽

Inorganic Perovskite ◽

Surface Ligands ◽

Perovskite Quantum Dots ◽

Stability Issue ◽

The Stability ◽

Nuclear Battery ◽

Cspbbr3 Quantum Dots

One of the main reasons for the stability issue of inorganic perovskite quantum dots (PQDs) is the fragile protection of surface ligands. Here, an armor-like passivation strategy is proposed to...

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Formation of Carbon Quantum Dots via Hydrothermal Carbonization: Investigate the Effect of Precursors

Energies ◽

10.3390/en14040986 ◽

2021 ◽

Vol 14 (4) ◽

pp. 986

Author(s):

Md Rifat Hasan ◽

Nepu Saha ◽

Thomas Quaid ◽

M. Toufiq Reza

Keyword(s):

Quantum Dots ◽

Optical Properties ◽

Microcrystalline Cellulose ◽

Uv Light ◽

Synthesis Method ◽

Hydrothermal Carbonization ◽

Carbon Quantum Dots ◽

Medical Diagnostics ◽

Particle Size Range ◽

Wide Range

Carbon quantum dots (CQDs) are nanomaterials with a particle size range of 2 to 10 nm. CQDs have a wide range of applications such as medical diagnostics, bio-imaging, biosensors, coatings, solar cells, and photocatalysis. Although the effect of various experimental parameters, such as the synthesis method, reaction time, etc., have been investigated, the effect of different feedstocks on CQDs has not been studied yet. In this study, CQDs were synthesized from hydroxymethylfurfural, furfural, and microcrystalline cellulose via hydrothermal carbonization at 220 °C for 30 min of residence time. The produced CQDs showed green luminescence behavior under the short-wavelength UV light. Furthermore, the optical properties of CQDs were investigated using ultraviolet-visible spectroscopy and emission spectrophotometer, while the morphology and chemical bonds of CQDs were investigated using transmission electron microscopy and Fourier-transform infrared spectroscopy, respectively. Results showed that all CQDs produced from various precursors have absorption and emission properties but these optical properties are highly dependent on the type of precursor. For instance, the mean particle sizes were 6.36 ± 0.54, 5.35 ± 0.56, and 3.94 ± 0.60 nm for the synthesized CQDs from microcrystalline cellulose, hydroxymethylfurfural, and furfural, respectively, which appeared to have similar trends in emission intensities. In addition, the synthesized CQDs experienced different functionality (e.g., C=O, O-H, C-O) resulting in different absorption behavior.

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Influence of Surface Ligands on the Luminescent Properties of Cadmium Selenide Quantum Dots in a Polymethylmethacrylate Matrix

Physics Procedia ◽

10.1016/j.phpro.2015.09.140 ◽

2015 ◽

Vol 73 ◽

pp. 150-155 ◽

Cited By ~ 3

Author(s):

M. Zvaigzne ◽

I. Martynov ◽

P. Samokhvalov ◽

K. Mochalov ◽

A. Chistyakov

Keyword(s):

Quantum Dots ◽

Cadmium Selenide ◽

Luminescent Properties ◽

Surface Ligands ◽

Cadmium Selenide Quantum Dots

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Multi-Quantum Dots-Embedded Silica-Encapsulated Nanoparticle-Based Lateral Flow Assay for Highly Sensitive Exosome Detection

Nanomaterials ◽

10.3390/nano11030768 ◽

2021 ◽

Vol 11 (3) ◽

pp. 768

Author(s):

Hyung-Mo Kim ◽

Chiwoo Oh ◽

Jaehyun An ◽

Seungki Baek ◽

Sungje Bock ◽

...

Keyword(s):

Quantum Dots ◽

Limit Of Detection ◽

Specific Binding ◽

Calf Serum ◽

Lateral Flow ◽

Lateral Flow Immunoassay ◽

Uniform Size ◽

Highly Sensitive ◽

Wide Range ◽

New Biomarkers

Exosomes are attracting attention as new biomarkers for monitoring the diagnosis and prognosis of certain diseases. Colorimetric-based lateral-flow assays have been previously used to detect exosomes, but these have the disadvantage of a high limit of detection. Here, we introduce a new technique to improve exosome detection. In our approach, highly bright multi-quantum dots embedded in silica-encapsulated nanoparticles (M–QD–SNs), which have uniform size and are brighter than single quantum dots, were applied to the lateral flow immunoassay method to sensitively detect exosomes. Anti-CD63 antibodies were introduced on the surface of the M–QD–SNs, and a lateral flow immunoassay with the M–QD–SNs was conducted to detect human foreskin fibroblast (HFF) exosomes. Exosome samples included a wide range of concentrations from 100 to 1000 exosomes/µL, and the detection limit of our newly designed system was 117.94 exosome/μL, which was 11 times lower than the previously reported limits. Additionally, exosomes were selectively detected relative to the negative controls, liposomes, and newborn calf serum, confirming that this method prevented non-specific binding. Thus, our study demonstrates that highly sensitive and quantitative exosome detection can be conducted quickly and accurately by using lateral immunochromatographic analysis with M–QD–SNs.

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Microplasma Band Structure Engineering in Graphene Quantum Dots for Sensitive and Wide-Range pH Sensing

ACS Applied Materials & Interfaces ◽

10.1021/acsami.1c18440 ◽

2021 ◽

Author(s):

Darwin Kurniawan ◽

Bai Amutha Anjali ◽

Owen Setiawan ◽

Kostya Ken Ostrikov ◽

Yongchul G. Chung ◽

...

Keyword(s):

Quantum Dots ◽

Band Structure ◽

Graphene Quantum Dots ◽

Ph Sensing ◽

Wide Range ◽

Structure Engineering

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Synthesis and Properties of Nitrogen-Doped Carbon Quantum Dots Using Lactic Acid as Carbon Source

Materials ◽

10.3390/ma15020466 ◽

2022 ◽

Vol 15 (2) ◽

pp. 466

Author(s):

Kaixin Chang ◽

Qianjin Zhu ◽

Liyan Qi ◽

Mingwei Guo ◽

Woming Gao ◽

...

Keyword(s):

Quantum Dots ◽

Lactic Acid ◽

Fluorescence Quenching ◽

Functional Groups ◽

Fluorescence Intensity ◽

Carbon Quantum Dots ◽

Nitrogen Doped ◽

Ph Values ◽

Wide Range ◽

Nitrogen Doped Carbon

Nitrogen-doped carbon quantum dots (N-CQDs) were synthesized in a one-step hydrothermal technique utilizing L-lactic acid as that of the source of carbon and ethylenediamine as that of the source of nitrogen, and were characterized using dynamic light scattering, X-ray photoelectron spectroscopy ultraviolet-visible spectrum, Fourier-transformed infrared spectrum, high-resolution transmission electron microscopy, and fluorescence spectrum. The generated N-CQDs have a spherical structure and overall diameters ranging from 1–4 nm, and their surface comprises specific functional groups such as amino, carboxyl, and hydroxyl, resulting in greater water solubility and fluorescence. The quantum yield of N-CQDs (being 46%) is significantly higher than that of the CQDs synthesized from other biomass in literatures. Its fluorescence intensity is dependent on the excitation wavelength, and N-CQDs release blue light at 365 nm under ultraviolet light. The pH values may impact the protonation of N-CQDs surface functional groups and lead to significant fluorescence quenching of N-CQDs. Therefore, the fluorescence intensity of N-CQDs is the highest at pH 7.0, but it decreases with pH as pH values being either more than or less than pH 7.0. The N-CQDs exhibit high sensitivity to Fe3+ ions, for Fe3+ ions would decrease the fluorescence intensity of N-CQDs by 99.6%, and the influence of Fe3+ ions on N-CQDs fluorescence quenching is slightly affected by other metal ions. Moreover, the fluorescence quenching efficiency of Fe3+ ions displays an obvious linear relationship to Fe3+ concentrations in a wide range of concentrations (up to 200 µM) and with a detection limit of 1.89 µM. Therefore, the generated N-CQDs may be utilized as a robust fluorescence sensor for detecting pH and Fe3+ ions.

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Carbon Based Nanodots in Early Diagnosis of Cancer

Frontiers in Chemistry ◽

10.3389/fchem.2021.669169 ◽

2021 ◽

Vol 9 ◽

Author(s):

Gurpal Singh ◽

Harinder Kaur ◽

Akanksha Sharma ◽

Joga Singh ◽

Hema Kumari Alajangi ◽

...

Keyword(s):

Quantum Dots ◽

Early Stage ◽

Imaging Techniques ◽

Graphene Quantum Dots ◽

Carbon Quantum Dots ◽

Diagnostic Methods ◽

Early Diagnosis Of Cancer ◽

Successful Treatment Outcome ◽

Wide Range ◽

Carbon Based

Detection of cancer at an early stage is one of the principal factors associated with successful treatment outcome. However, current diagnostic methods are not capable of making sensitive and robust cancer diagnosis. Nanotechnology based products exhibit unique physical, optical and electrical properties that can be useful in diagnosis. These nanotech-enabled diagnostic representatives have proved to be generally more capable and consistent; as they selectively accumulated in the tumor site due to their miniscule size. This article rotates around the conventional imaging techniques, the use of carbon based nanodots viz Carbon Quantum Dots (CQDs), Graphene Quantum Dots (GQDs), Nanodiamonds, Fullerene, and Carbon Nanotubes that have been synthesized in recent years, along with the discovery of a wide range of biomarkers to identify cancer at early stage. Early detection of cancer using nanoconstructs is anticipated to be a distinct reality in the coming years.

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