Sequential Structural Degradation of Red Perovskite Quantum Dots and Its Prevention by Introducing Iodide at a Stable Gradient Concentration into the Core–Shell Red Perovskite Quantum Dots

Nanoscale ◽  
2022 ◽  
Author(s):  
Hanleem Lee ◽  
Cuc Kim Trinh ◽  
Mo Geun So ◽  
Chang-Lyoul Lee
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Core Shell ◽  
Next Generation ◽  
Structural Degradation ◽  
The Core ◽  
Perovskite Quantum Dots ◽  
Structural Instabilities

Perovskite quantum dots (QDs) have been extensively studied as emissive materials for next-generation optoelectronics due to their outstanding optical properties; however, their structural instabilities, specifically those of red perovskite QDs,...

Synthesis and Characterization of the Core-Shell CdTe/ZnS Quantum Dots

2009 ◽  
Vol 60-61 ◽  
pp. 165-169 ◽  
Author(s):  
Shi Chao Xu ◽  
Cui Cui Yao ◽  
Ji Mei Zhang ◽  
Zhao Dai ◽  
Guo Zheng ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Colloidal Particles ◽  
Resonance Energy ◽  
Quantum Yields ◽  
Diagnostic Process ◽  
Core Shell ◽  
The Core ◽  
Average Size ◽  
Cdte Core

Core-shell quantum dots are colloidal particles consisting of a semiconductor core and a shell material as an outer coating layer. It can be utilized to develop sensitive methods for the detection of specific biological entities, such as microbial species, their transcription products, and single genes etc. The goal of current research is to synthesize CdTe and core-shell CdTe/ZnS quantum dots (QDs) with an improved process, and to investigate their properties. Well-dispersed CdTe core was prepared in aqueous phase with using 3-mercaptopropionic acid (MPA) as stabilizer under conditions of pH 9.1, temperature of 100 °C, refluxing for 6h, and mol ratio of Cd2+/Te2-/MPA is 1:0.5:2.4. Average size of 8 nm CdTe core was conformed via transmission electron microscopy (TEM). Core-shell CdTe/ZnS QDs were then synthesized to improve the optical properties and biocompatibility of CdTe core. Various conditions were researched to obtain the core-shell QDs with the best optical properties, such as quantum yields, fluorescence intensity etc. The results indicated that the core-shell qualified CdTe/ZnS was prepared under conditions of pH 9.0, temperature of 45 °C, refluxing for 1h, and mol ratio of CdTe/S2-/Zn2+ is 4/1/1. CdTe/ZnS with average size of 10 nm were achieved and conformed via TEM. Moreover, red shift of a maximum emission wavelength from 547 nm of CdTe to 587 of CdTe/ZnS was observed via fluorescence spectrum (FS), which inferred the growth of QDs and formation of ZnS shells. The achieved ZnS shell make CdTe core less toxic and more biocompatible, it will be useful in biological labeling, diagnostic process and biosensing system based on fluorescence resonance energy transition (FRET).

scholarly journals The Performance of Active Coated Nanoparticles Based on Quantum-Dot Gain Media

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Sawyer D. Campbell ◽  
Richard W. Ziolkowski
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Quantum Dot ◽  
Relative Size ◽  
Core Shell ◽  
The Core ◽  
Coated Nanoparticles ◽  
Dot Gain ◽  
Band Gap Structure ◽  
Gain Media

Quantum-dots (QDs) provide an exciting option for the gain media incorporated in active coated nanoparticles (CNPs) because they possess large gain coefficients resulting from their extreme confinement effects. The optical properties of core/shell QDs can be tuned by changing the relative size of the core/shell, that is, by effectively changing its band gap structure. Similarly, the resonance of a CNP can be adjusted by changing the relative sizes of its layers. It is demonstrated here that by optimally locating the QDs inside a resonant CNP structure it is possible to greatly enhance the intrinsic amplifying behavior of the combined QD-CNP system.

scholarly journals Ge/Si core/shell quantum dots in alumina: tuning the optical absorption by the core and shell size

Nanophotonics ◽  
2017 ◽  
Vol 6 (5) ◽  
pp. 1055-1062 ◽  
Author(s):  
Nikolina Nekić ◽  
Jordi Sancho-Parramon ◽  
Ivančica Bogdanović-Radović ◽  
Jörg Grenzer ◽  
René Hübner ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Blue Shift ◽  
Core Shell ◽  
Shell Size ◽  
Experimental Realization ◽  
Sputtering Deposition ◽  
The Core ◽  
Theoretical Predictions ◽  
The Matrix

AbstractGe/Si core/shell quantum dots (QDs) recently received extensive attention due to their specific properties induced by the confinement effects of the core and shell structure. They have a type II confinement resulting in spatially separated charge carriers, the electronic structure strongly dependent on the core and shell size. Herein, the experimental realization of Ge/Si core/shell QDs with strongly tunable optical properties is demonstrated. QDs embedded in an amorphous alumina glass matrix are produced by simple magnetron sputtering deposition. In addition, they are regularly arranged within the matrix due to their self-assembled growth regime. QDs with different Ge core and Si shell sizes are made. These core/shell structures have a significantly stronger absorption compared to pure Ge QDs and a highly tunable absorption peak dependent on the size of the core and shell. The optical properties are in agreement with recent theoretical predictions showing the dramatic influence of the shell size on optical gap, resulting in 0.7 eV blue shift for only 0.4 nm decrease at the shell thickness. Therefore, these materials are very promising for light-harvesting applications.

Investigation of the Surface Passivation Effect on the Optical Properties of CsPbBr3 Perovskite Quantum Dots

2021 ◽  
Vol 23 ◽  
pp. 100948
Author(s):  
Saif M.H. Qaid ◽  
Hamid M. Ghaithan ◽  
Bandar Ali Al-Asbahi ◽  
Abdullah S. Aldwayyan
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Surface Passivation ◽  
Perovskite Quantum Dots

scholarly journals Light-Scattering Simulations from Spherical Bimetallic Core–Shell Nanoparticles

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 359
Author(s):  
Francesco Ruffino
Keyword(s):  
Optical Properties ◽  
Light Scattering ◽  
Bimetallic Nanoparticles ◽  
Dominant Role ◽  
Scattered Light ◽  
Specific Interaction ◽  
Surface Enhanced Raman Spectroscopy ◽  
Localized Surface Plasmon ◽  
Core Shell ◽  
The Core

Bimetallic nanoparticles show novel electronic, optical, catalytic or photocatalytic properties different from those of monometallic nanoparticles and arising from the combination of the properties related to the presence of two individual metals but also from the synergy between the two metals. In this regard, bimetallic nanoparticles find applications in several technological areas ranging from energy production and storage to sensing. Often, these applications are based on optical properties of the bimetallic nanoparticles, for example, in plasmonic solar cells or in surface-enhanced Raman spectroscopy-based sensors. Hence, in these applications, the specific interaction between the bimetallic nanoparticles and the electromagnetic radiation plays the dominant role: properties as localized surface plasmon resonances and light-scattering efficiency are determined by the structure and shape of the bimetallic nanoparticles. In particular, for example, concerning core-shell bimetallic nanoparticles, the optical properties are strongly affected by the core/shell sizes ratio. On the basis of these considerations, in the present work, the Mie theory is used to analyze the light-scattering properties of bimetallic core–shell spherical nanoparticles (Au/Ag, AuPd, AuPt, CuAg, PdPt). By changing the core and shell sizes, calculations of the intensity of scattered light from these nanoparticles are reported in polar diagrams, and a comparison between the resulting scattering efficiencies is carried out so as to set a general framework useful to design light-scattering-based devices for desired applications.

scholarly journals Effect of dopant concentration and the role of ZnS shell on optical properties of Sm3+ doped CdS quantum dots

RSC Advances ◽  
2021 ◽  
Vol 11 (14) ◽  
pp. 7961-7971
Author(s):  
N. D. Vinh ◽  
P. M. Tan ◽  
P. V. Do ◽  
S. Bharti ◽  
V. X. Hoa ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Dopant Concentration ◽  
Core Shell ◽  
Cds Quantum Dots ◽  
Cds Qds

The role of samarium (Sm) dopant on the structural, morphological, and optical properties of CdS QDs and CdS/ZnS core/shell QDs was methodically reported.

Effect of ZnS shell on optical properties of CdSe–ZnS core–shell quantum dots

2015 ◽  
Vol 39 ◽  
pp. 46-51 ◽  
Author(s):  
S. Mathew ◽  
Bishwajeet Singh Bhardwaj ◽  
Amit D. Saran ◽  
P. Radhakrishnan ◽  
V.P.N. Nampoori ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Core Shell
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