scholarly journals Bright and Compact Alloyed Quantum Dots with Broadly Tunable Near-Infrared Absorption and Fluorescence Spectra through Mercury Cation Exchange

2011 ◽  
Vol 133 (1) ◽  
pp. 24-26 ◽  
Author(s):  
Andrew M. Smith ◽  
Shuming Nie
Keyword(s):  
Quantum Dots ◽  
Cation Exchange ◽  
Infrared Absorption ◽  
Fluorescence Spectra ◽  
Near Infrared ◽  
Absorption And Fluorescence Spectra

A phthalocyanine-based fluorescent sensor for Zn2+ ion

2013 ◽  
Vol 17 (01n02) ◽  
pp. 99-103 ◽  
Author(s):  
Hui He ◽  
Jian-Yong Liu ◽  
Dennis K.P. Ng
Keyword(s):  
Metal Ions ◽  
Spectral Properties ◽  
Fluorescence Spectra ◽  
Near Infrared ◽  
Fluorescent Sensor ◽  
High Sensitivity ◽  
Absorption And Fluorescence Spectra

This paper describes the preparation and spectral properties of a near-infrared fluorophore in which two bis(2-picolyl)amino moieties are axially linked to a silicon(IV) phthalocyanine core. The effects of various metal ions on its absorption and fluorescence spectra have been examined. The results indicate that this compound shows a high sensitivity and moderate selectivity toward Zn2+ ion.

scholarly journals Retraction: A facile cation exchange-based aqueous synthesis of highly stable and biocompatible Ag2S quantum dots emitting in the second near-infrared biological window

2020 ◽  
Vol 49 (41) ◽  
pp. 14706-14706
Author(s):  
Andrew Shore
Keyword(s):  
Quantum Dots ◽  
Cation Exchange ◽  
Near Infrared ◽  
Aqueous Synthesis ◽  
Dalton Trans ◽  
Ag2s Quantum Dots

Retraction of ‘A facile cation exchange-based aqueous synthesis of highly stable and biocompatible Ag2S quantum dots emitting in the second near-infrared biological window’ by Rijun Gui et al., Dalton Trans., 2014, 43, 16690–16697, DOI: 10.1039/C4DT00699B.

scholarly journals Bacterial Synthesis of Ternary CdSAg Quantum Dots through Cation Exchange: Tuning the Composition and Properties of Biological Nanoparticles for Bioimaging and Photovoltaic Applications

2020 ◽  
Vol 8 (5) ◽  
pp. 631 ◽  
Author(s):  
Nicolás Órdenes-Aenishanslins ◽  
Giovanna Anziani-Ostuni ◽  
Juan Pablo Monrás ◽  
Alejandra Tello ◽  
Denisse Bravo ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cation Exchange ◽  
Near Infrared ◽  
Fluorescent Dyes ◽  
Exchange Process ◽  
Water Soluble ◽  
Partial Replacement ◽  
Biological Synthesis ◽  
Bacterial Cells ◽  
First Time

In this study, we introduce a biological method for the production of ternary Quantum Dots (QDs): complex nanostructures with tunable optical and structural properties that utilizes post-synthesis modifications through cation exchange. This versatile in-situ cation exchange method being reported for the first time shows great potential for extending the scope of microbial synthesis. By using this bacterial-based method, we easily synthesize and purify CdS, CdSAg, and Ag2S nanocrystals of a size below 15 nm and with variable morphologies that exhibit fluorescence emissions covering a broad spectral range (from 400 to 800 nm). Energy-dispersive X-ray spectroscopy (EDS) results indicate the partial replacement of Cd2+ by Ag+ when AgNO3 concentration is increased. This replacement produces CdSAg ternary QDs hetero-structures with high stability, fluorescence in the NIR-I (700 - 800 nm), and 36.13% quantum yield. Furthermore, this reaction can be extended for the production of soluble Ag2S nanoparticles (NPs) without any traces of Cd. QDs biosynthesized through this cation exchange process display very low toxicity when tested in bacterial or human cell lines. Biosynthesized ternary hetero-structures were used as red fluorescent dyes to label HeLa cells in confocal microscopy studies, which validates its use in bioimaging applications in the near infrared region. In addition, the application of biologically-produced cadmium NPs in solar cells is reported for the first time. The three biosynthesized QDs were successfully used as photosensitizers, where the CdSAg QDs show the best photovoltaic parameters. Altogether, obtained results validate the use of bacterial cells for the controlled production of nanomaterials with properties that allow their application in diverse technologies. We developed a simple biological process for obtaining tunable Quantum Dots (QDs) with different metal compositions through a cation exchange process. Nanoparticles (NPs) are produced in the extracellular space of bacterial cells exposed to cysteine and CdCl2 in a reaction that depends on S2− generation mediated by cysteine desulfhydrase enzymes and uses cellular biomolecules to stabilize the nanoparticle. Using this extracellular approach, water-soluble fluorescent CdS, CdSAg, and Ag2S Quantum Dots with a tunable emission ranging from 400 to 800 nm were generated. This is the first study reporting the use of microorganisms to produce tunable ternary QDs and the first time that a cation exchange process mediated by cells is described. Obtained results validate the use of biological synthesis to produce NPs with new characteristics and opens a completely new research field related to the use of microorganisms to synthesize complex NPs that are difficult to obtain with regular chemical methods.

scholarly journals Synthesis of efficient near-infrared-emitting CuInS2/ZnS quantum dots by inhibiting cation-exchange for bio application

RSC Advances ◽  
2017 ◽  
Vol 7 (18) ◽  
pp. 10675-10682 ◽  
Author(s):  
Yi su Kim ◽  
Yonghee Lee ◽  
Youngsun Kim ◽  
Donghyuk Kim ◽  
Hyung Seok Choi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Temperature Dependence ◽  
Cation Exchange ◽  
Near Infrared ◽  
Shell Growth ◽  
Cationic Exchange

Near-infrared (NIR)-emitting CuInS2(CIS)/ZnS quantum dots (QDs) were synthesized, and we investigated temperature-dependence of cationic exchange during ZnS shell growth. The obtained QDs were transformed to nanocapsules for bio-application.

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