Photochemical synthesis, investigation of optical properties and photocatalytic activity of CdTe/CdSe core/shell quantum dots

2021 ◽  
pp. 1-7
Author(s):  
Mehdi Molaei ◽  
Farzad Farahmandzadeh ◽  
Tahereh Sadat Mousavi ◽  
Masoud Karimipour
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Photocatalytic Activity ◽  
Photochemical Synthesis ◽  
Core Shell ◽  
Cdse Core

scholarly journals Synthesis and Optical Properties of Thiol Functionalized CdSe/ZnS (Core/Shell) Quantum Dots by Ligand Exchange

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Huaping Zhu ◽  
Michael Z. Hu ◽  
Lei Shao ◽  
Kui Yu ◽  
Reza Dabestani ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Ligand Exchange ◽  
Surface Passivation ◽  
Emission Spectra ◽  
Trioctylphosphine Oxide ◽  
Core Shell ◽  
Initial Surface ◽  
Cdse Core ◽  
Surface Modified

The colloidal photoluminescent quantum dots (QDs) of CdSe (core) and CdSe/ZnS (core/shell) were synthesized at different temperatures with different growth periods. Optical properties (i.e., UV/Vis spectra and photoluminescent emission spectra) of the resulting QDs were investigated. The shell-protected CdSe/ZnS QDs exhibited higher photoluminescent (PL) efficiency and stability than their corresponding CdSe core QDs. Ligand exchange with various thiol molecules was performed to replace the initial surface passivation ligands, that is, trioctylphosphine oxide (TOPO) and trioctylphosphine (TOP), and the optical properties of the surface-modified QDs were studied. The thiol ligand molecules in this study included 1,4-benzenedimethanethiol, 1,16-hexadecanedithiol, 1,11-undecanedithiol, biphenyl-4,4′-dithiol, 11-mercapto-1-undecanol, and 1,8-octanedithiol. After the thiol functionalization, the CdSe/ZnS QDs exhibited significantly enhanced PL efficiency and storage stability. Besides surface passivation effect, such enhanced performance of thiol-functionalized QDs could be due to cross-linked assembly formation of dimer/trimer clusters, in which QDs are linked by dithiol molecules. Furthermore, effects of ligand concentration, type of ligand, and heating on the thiol stabilization of QDs were also discussed.

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

scholarly journals Ultrafast optical properties of type-II CdZnS/ZnSe core-shell quantum dots

2018 ◽  
Vol 26 (14) ◽  
pp. 18480 ◽  
Author(s):  
Lingling Ran ◽  
Haiyang Li ◽  
Wenzhi Wu ◽  
Yachen Gao ◽  
Zhijun Chai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Core Shell ◽  
Type Ii ◽  
Ultrafast Optical

Resistive Switching in CdTe/CdSe Core–Shell Quantum Dots Embedded Chitosan-Based Memory Devices

2021 ◽  
Author(s):  
Zolile Wiseman Dlamini ◽  
Sreedevi Vallabhapurapu ◽  
Olamide Abiodun Daramola ◽  
Potlaki Foster Tseki ◽  
Rui Werner Macedo Krause ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Resistive Switching ◽  
Core Shell ◽  
Cdse Core ◽  
Active Layers ◽  
Ag Electrodes ◽  
Exponential Decrease ◽  
Conductive Bridge ◽  
Bipolar Memory ◽  
State Resistance

In this paper, we report on the resistive switching (RS) and conduction mechanisms in devices consisting of CdTe/CdSe core–shell quantum dots embedded chitosan composites active layer. Two devices with active layers sandwiched between (1) Al and Ag, and (2) ITO and Ag electrodes were studied. Both devices exhibited bipolar memory behavior with [Formula: see text] V and [Formula: see text][Formula: see text]V, for the Al-based device, while [Formula: see text] V and [Formula: see text][Formula: see text]V were observed for the ITO-based device, enabling both devices to be operated at low powers. However, the switching mechanisms of both devices were different, i.e., RS in Al device was attributed to conductive bridge mechanism, while space-charge-limited driven conduction filament attributed the switching mechanism of the ITO device. Additionally, the Al-based device showed long retention ([Formula: see text][Formula: see text]s) and a reasonable large ([Formula: see text]) ON/OFF ratio. Additionally, for this device, we also observed sweeping cycle-induced reversal of voltage polarity of the [Formula: see text] and [Formula: see text]. In contrast, we observed that increasing sweeping cycles resulted in an exponential decrease of the OFF-state resistance of the ITO-based device.

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