Effect of concentration and shell thickness on the optical behavior of aqueous CdTe/ZnSe core/shell quantum dots (QDs) exposed to ionizing radiation

Luminescence ◽  
2022 ◽  
Author(s):  
Farzad Farahmandzadeh ◽  
Mehdi Molaei ◽  
Hassan Alehdaghi ◽  
Masoud Karimipour ◽  
Alireza Shamsi
Keyword(s):  
Quantum Dots ◽  
Ionizing Radiation ◽  
Shell Thickness ◽  
Core Shell ◽  
Optical Behavior

scholarly journals Quantum Confinement Effect and Photoenhancement of Photoluminescence of PbS and PbS/MnS Quantum Dots

2020 ◽  
Vol 10 (18) ◽  
pp. 6282
Author(s):  
Muhammad Safwan Zaini ◽  
Josephine Ying Chyi Liew ◽  
Shahrul Ainliah Alang Ahmad ◽  
Abdul Rahman Mohmad ◽  
Mazliana Ahmad Kamarudin
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Quantum Confinement ◽  
Shell Thickness ◽  
Quantum Confinement Effect ◽  
Band Gap Energy ◽  
Confinement Effect ◽  
Core Shell ◽  
Lead Sulphide ◽  
Peak Energy

The quantum confinement effect and photoenhancement of photoluminescence (PL) of lead sulphide (PbS) quantum dots (QDs) and lead sulphide/manganese sulphide (PbS/MnS) core shell QDs capped with thiol ligands in aqueous solution were investigated. From PL results, the presence of MnS shells gives a strong confinement effect which translates to higher emission energy in PbS/MnS core shell QDs. Increasing MnS shell thickness from 0.3 to 1.5 monolayers (ML) causes a blueshift of PL peak energies as the charge carriers concentrated in the PbS core region. Enhancement of the PL intensity of colloidal PbS and PbS/MnS core shell QDs has been observed when the samples are illuminated above the band gap energy, under continuous irradiation for 40 min. Luminescence from PbS QDs and PbS/MnS core shell QDs can be strongly influenced by the interaction of water molecules and oxygen present in aqueous solution adsorbed on the QD surface. However, PbS/MnS core shell QDs with a shell thickness of 1.5 ML did not show a PL peak energy stability as it was redshifted after 25 min, probably due to wider size distribution of the QDs.

Interband Optical Transition Energies in Type-II PbSe/PbS Core/Shell Quantum Dots

2017 ◽  
Vol 6 (1) ◽  
pp. 80-86
Author(s):  
S. N. Saravanamoorthy ◽  
A. John Peter
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Shell Thickness ◽  
Optical Transition ◽  
Hole Pair ◽  
Core Shell ◽  
Type Ii ◽  
Electron Hole ◽  
Transition Energies ◽  
Electron Hole Pair

Electronic and optical properties of Type-II lead based core/shell semiconducting quantum dots are reported. Binding energies of electron–hole pair, optical transition energies and the absorption coefficients are investigated taking into account the geometrical confinement in PbSe/PbS core/shell quantum dot nanostructure. The energies are obtained with the increase of shell thickness for various inner core radii. The probability densities of electron and hole wave functions of radial coordinate of the core PbSe and PbS shell quantum dots are presented. The optical transition energy with the spatial confinement is brought out. The electronic properties are obtained using variational approach whereas the compact density matrix method is employed for the nonlinear optical properties. The results show that (i) a decrease in binding energy is obtained when the shell thickness increases due to more separation of electron–hole pair and (ii) the energy band gap decreases with the increase in the shell thickness resulting in the reduction of the higher energy interband transitions.

scholarly journals Effects of shell thickness on the electric field dependence of exciton recombination in CdSe/CdS core/shell quantum dots

2017 ◽  
Vol 7 (6) ◽  
pp. 1871 ◽  
Author(s):  
Clare E. Rowland ◽  
Marc Currie ◽  
Kimihiro Susumu ◽  
Eunkeu Oh ◽  
Gary Kushto ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electric Field ◽  
Field Dependence ◽  
Shell Thickness ◽  
Core Shell ◽  
Electric Field Dependence ◽  
Exciton Recombination

Shell-Thickness-Dependent Biexciton Lifetime in Type I and Quasi-Type II CdSe@CdS Core/Shell Quantum Dots

2018 ◽  
Vol 122 (25) ◽  
pp. 14091-14098 ◽  
Author(s):  
Degui Kong ◽  
Yanyan Jia ◽  
Yueping Ren ◽  
Zhaoxiong Xie ◽  
Kaifeng Wu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Shell Thickness ◽  
Core Shell ◽  
Type I ◽  
Type Ii

Interfacial strain and shell thickness effect on core squeeze/stretch in core/shell quantum dots

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Negar Gheshlaghi ◽  
Mehrdad Faraji ◽  
Hadi Sedaghat Pisheh
Keyword(s):  
Quantum Dots ◽  
Shell Thickness ◽  
Thickness Effect ◽  
Core Shell ◽  
Interfacial Strain

scholarly journals Enhancing photo-reduction quantum efficiency using quasi-type II core/shell quantum dots

2016 ◽  
Vol 7 (7) ◽  
pp. 4125-4133 ◽  
Author(s):  
Yanyan Jia ◽  
Jinquan Chen ◽  
Kaifeng Wu ◽  
Alex Kaledin ◽  
Djamaladdin G. Musaev ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Quantum Efficiency ◽  
Shell Thickness ◽  
Removal Rate ◽  
Core Shell ◽  
Type Ii ◽  
Fast Increase

Enhancing photoreduction quantum yield in core/shell QDs through an unexpectedly fast increase of hole removal rate with shell thickness.

Structural and optical behavior of hexa-propyl methyl cellulose (HPMC) capped ZnS core–shell quantum dots

2015 ◽  
Vol 26 (8) ◽  
pp. 5980-5986 ◽  
Author(s):  
H. C. Jeon ◽  
T. W. Kang ◽  
Anupriya Jain ◽  
Sanjay Panwar ◽  
Suman Bala ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Methyl Cellulose ◽  
Core Shell ◽  
Optical Behavior
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