A steady-state and time-resolved photophysical study of CdTe quantum dots in water

2015 ◽  
Vol 14 (2) ◽  
pp. 397-406 ◽  
Author(s):  
Alessandro Iagatti ◽  
Luigi Tarpani ◽  
Eleonora Fiacchi ◽  
Laura Bussotti ◽  
Agnese Marcelli ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Steady State ◽  
Cdte Quantum Dots ◽  
Capping Agent ◽  
Electron Hole ◽  
Time Resolved ◽  
Cdte Qds ◽  
Recombination Processes ◽  
Photophysical Study ◽  
Hole Recombination

The non-radiative electron–hole recombination processes are predominant in alkyl-thiol capped CdTe QDs prepared in water and they are affected by the nature of the capping agent.

RECOMBINATION PROCESSES IN SYSTEMS BASED ON IONIC CRYSTALS WITH EMBEDDED SELF-ORGANIZED NANOCRYSTALS

2007 ◽  
Vol 06 (05) ◽  
pp. 311-314 ◽  
Author(s):  
N. G. ROMANOV ◽  
A. G. BADALYAN ◽  
D. O. TOLMACHEV ◽  
V. L. PREOBRAZHENSKI ◽  
P. G. BARANOV ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Crystal Lattice ◽  
The Self ◽  
Ionic Crystals ◽  
Electron Hole ◽  
Self Organized ◽  
Recombination Processes ◽  
Low Dimensional ◽  
Hole Centers ◽  
Hole Recombination

The recombination processes leading to tunneling afterglow and photostimulated luminescence were studied in systems based on ionic host crystals with low-dimensional structures (semiconductor quantum dots) formed as a result of the self-organized growth. The systems of AgBr nanocrystals embedded into the KBr crystal lattice and CsPbBr 3 nanocrystals embedded into the CsBr crystal lattice were investigated. The energy of electron–hole recombination in matrices was shown to transfer to quantum dots. To identify the structure of recombining electron and hole centers, magnetic resonance detected optically by monitoring the tunneling afterglow was used.

scholarly journals Steady-state and nanosecond time-resolved photoluminescence spectroscopies of aqueous CdTe quantum dots

2007 ◽  
Vol 56 (5) ◽  
pp. 2926
Author(s):  
Wu Wen-Zhi ◽  
Yan Yu-Xi ◽  
Zheng Zhi-Ren ◽  
Jin Qin-Han ◽  
Liu Wei-Long ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Steady State ◽  
Cdte Quantum Dots ◽  
Time Resolved ◽  
Time Resolved Photoluminescence

Photoluminescent Properties of TGA-Capped CdTe Quantum Dots

2011 ◽  
Vol 306-307 ◽  
pp. 1262-1265 ◽  
Author(s):  
Zhi Min Yuan ◽  
Jie Yang ◽  
Yu Lan Zhang ◽  
Rui Li Zhang ◽  
Ning Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Cdte Quantum Dots ◽  
Molar Ratio ◽  
Average Lifetime ◽  
Capping Agent ◽  
Peak Wavelength ◽  
Preparation Conditions ◽  
Cdte Qds ◽  
Increasing Temperature

An environmentally friendly synthesis was developed to fabricate aqueous CdTe quantum dots (QDs) using thilglycolic acid (TGA) as a capping agent. Optimal preparation conditions including pH (11.2) and TGA/Cd molar ratio (1.5:1) resulted in CdTe QDs with high photoluminescence (PL) quantum yield up to 56%. The TGA-capped CdTe QDs exhibited tunable PL from green to red. Lifetime measurement indicated that the average lifetime of the TGA-capped QDs increased with increasing their sizes (27.5 and 37.2 ns for the QDs with PL peak wavelength of 607 and 636 nm, respectively). The PL of the QDs revealed the dependence of temperature, in which the QDs exhibited a red-shifted PL peak with increasing temperature. Such PL behavior depended strongly on the QD sizes.

Electrostatic repulsion strategy for highly selective and sensitive “switch–on” fluorescence sensor of ascorbic acid based on the cysteamine-coated CdTe quantum dots and cerium (IV)

2021 ◽  
Author(s):  
Yifei Guo ◽  
Jingjing Du ◽  
Jianjun Li ◽  
Ran Yang ◽  
Peter B. de Harrington ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ascorbic Acid ◽  
Hydrothermal Method ◽  
Cadmium Chloride ◽  
Fluorescence Sensor ◽  
Cdte Quantum Dots ◽  
Electrostatic Repulsion ◽  
Functional Monomer ◽  
Simple Hydrothermal Method ◽  
Cdte Qds

In this work, cysteamine-coated CdTe quantum dots (CA-CdTe QDs) were synthesized by a simple hydrothermal method employing cadmium chloride as the cadmium source and cysteamine hydrochloride as the functional monomer....

A simple paper-based approach for arsenic determination in water using hydride generation coupled with mercaptosuccinic-acid capped CdTe quantum dots

2020 ◽  
Vol 12 (21) ◽  
pp. 2718-2726
Author(s):  
Oraphan Thepmanee ◽  
Kanlaya Prapainop ◽  
Obnithi Noppha ◽  
Nuanlaor Rattanawimanwong ◽  
Weena Siangproh ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Hydride Generation ◽  
Cdte Quantum Dots ◽  
Mercaptosuccinic Acid ◽  
Cdte Qds ◽  
Arsenic Detection ◽  
Detection Probe ◽  
Arsenic Determination

Paper-based device with MSA-CdTe QDs as arsenic detection probe is presented.

scholarly journals Silver ion-doped CdTe quantum dots as fluorescent probe for Hg2+ detection

RSC Advances ◽  
2020 ◽  
Vol 10 (64) ◽  
pp. 38965-38973
Author(s):  
Huazheng Li ◽  
Wangwei Lu ◽  
Gaoling Zhao ◽  
Bin Song ◽  
Jing Zhou ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Fluorescent Probe ◽  
Fluorescence Intensity ◽  
Silver Ion ◽  
Cdte Quantum Dots ◽  
Detection Range ◽  
Cdte Qds ◽  
Linear Relationships ◽  
The Relationship

Ag-doped CdTe QDs emit multiple-fluorescence peaks, and the relationship between fluorescence intensity and the concentration of Hg2+ is established. Two linear relationships are obtained, which is benefit to the extension of detection range.

scholarly journals Low-frequency lattice phonons in halide perovskites explain high defect tolerance toward electron-hole recombination

2020 ◽  
Vol 6 (7) ◽  
pp. eaaw7453 ◽  
Author(s):  
Weibin Chu ◽  
Qijing Zheng ◽  
Oleg V. Prezhdo ◽  
Jin Zhao ◽  
Wissam A. Saidi
Keyword(s):  
Low Cost ◽  
Low Frequency ◽  
Nonradiative Recombination ◽  
Defect Tolerance ◽  
Electron Hole ◽  
Surface Hopping ◽  
Recombination Processes ◽  
Halide Perovskites ◽  
Electron And Hole States ◽  
Hole Recombination

Low-cost solution-based synthesis of metal halide perovskites (MHPs) invariably introduces defects in the system, which could form Shockley-Read-Hall (SRH) electron-hole recombination centers detrimental to solar conversion efficiency. Here, we investigate the nonradiative recombination processes due to native point defects in methylammonium lead halide (MAPbI3) perovskites using ab initio nonadiabatic molecular dynamics within surface-hopping framework. Regardless of whether the defects introduce a shallow or deep band state, we find that charge recombination in MAPbI3 is not enhanced, contrary to predictions from SRH theory. We demonstrate that this strong tolerance against defects, and hence the breakdown of SRH, arises because the photogenerated carriers are only coupled with low-frequency phonons and electron and hole states overlap weakly. Both factors appreciably decrease the nonadiabatic coupling. We argue that the soft nature of the inorganic lattice with small bulk modulus is key for defect tolerance, and hence, the findings are general to other MHPs.

EXCITONIC SIDE BANDS OF INNER-SHELL EXCITATIONS IN RARE GAS SOLIDS

2002 ◽  
Vol 09 (02) ◽  
pp. 1333-1338 ◽  
Author(s):  
S. VIELHAUER ◽  
M. KIRM ◽  
V. KISAND ◽  
E. NEGODIN ◽  
E. SOMBROWSKI ◽  
...  
Keyword(s):  
Free Exciton ◽  
Rare Gas ◽  
Excitation Threshold ◽  
Energy Position ◽  
Excitation Spectra ◽  
Electron Hole ◽  
Time Resolved ◽  
Ionization Limit ◽  
Time Resolved Photoluminescence ◽  
Hole Recombination

Valence-exciton luminescence under inner-shell excitation of the rare gas solids Xe, Kr, and Ar has been measured using time-resolved photoluminescence. Two different processes for exciton creation can be distinguished: creation of "prompt" excitons immediately after excitation (within the experimental time resolution), and creation of "delayed" excitons through electron–hole recombination. The decay structure of the exciton emission in the range of inner-shell excitation is characterized by the coexistence of the two processes. Time-resolved excitation spectra near the 2p edge in Ar, the 3d edge in Kr, and the 4d edge in Xe are discussed. The process of prompt exciton creation is strongly enhanced above an excitation threshold at the energy position of the ionization limit of the core state plus the energy of the valence free exciton.

Steady-state and time-resolved fluorescence studies on interactions of carbon “quantum” dots with nitrotoluenes

2017 ◽  
Vol 468 ◽  
pp. 300-307 ◽  
Author(s):  
Gregory E. LeCroy ◽  
K.A. Shiral Fernando ◽  
Christopher E. Bunker ◽  
Ping Wang ◽  
Nicholas Tomlinson ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Steady State ◽  
Carbon Quantum Dots ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Fluorescence Studies
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