Theory of time-resolved Raman scattering and fluorescence emission from semiconductor quantum dots

2010 ◽  
Vol 81 (7) ◽  
Author(s):  
Julia Kabuss ◽  
Stefan Werner ◽  
Axel Hoffmann ◽  
Peter Hildebrandt ◽  
Andreas Knorr ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Raman Scattering ◽  
Fluorescence Emission ◽  
Semiconductor Quantum Dots ◽  
Time Resolved

EXCITON-MEDIATED RAMAN SCATTERING IN ONE-DIMENSIONAL QUANTUM DOTS

2011 ◽  
Vol 25 (32) ◽  
pp. 4387-4393 ◽  
Author(s):  
HAI-CHAO SUN ◽  
CUI-HONG LIU
Keyword(s):  
Quantum Dots ◽  
Differential Cross Section ◽  
Raman Scattering ◽  
Cross Section ◽  
Differential Cross ◽  
Semiconductor Quantum Dots ◽  
Scattering Process ◽  
One Dimensional ◽  
Intermediate States ◽  
Potential Frequency

The differential cross section (DCS) for exciton-mediated Raman scattering (EMRS) in one-dimensional semiconductor quantum dots is presented. The exciton states are considered as intermediate states in the Raman scattering process. The selection rules for the EMRS process are studied. The numerical results show that the contribution to DCS indicated by exciton is larger than that by electron. DCS of EMRS is larger when there is a bigger confinement potential frequency.

FRET Study Between Carbon Quantum Dots and Malachite Green by Steady-State and Time-Resolved Fluorescence Spectroscopy

2020 ◽  
Vol 10 (3) ◽  
pp. 178-188
Author(s):  
Bipin Rooj ◽  
Ankita Dutta ◽  
Debojyoti Mukherjee ◽  
Sahidul Islam ◽  
Ujjwal Mandal
Keyword(s):  
Quantum Dots ◽  
Energy Transfer ◽  
Fluorescence Spectroscopy ◽  
Malachite Green ◽  
Dye Degradation ◽  
Fluorescence Emission ◽  
Carbon Quantum Dots ◽  
Time Resolved Fluorescence ◽  
Physical Processes ◽  
Time Resolved

Background: Understanding the interaction between different organic dyes and carbon quantum dots helps us to understand several photo physical processes like electron transfer, energy transfer, molecular sensing, drug delivery and dye degradation processes etc. Objective: The primary objective of this study is to whether the carbon quantum dots can act as an electron donor and can participate in the different photo physical processes. Methods: In this work, Carbon Quantum Dots (CQDLs) are synthesized in most economical and simple carbonization method where petals of Nelumbo nucifera L. are used as a carbon precursor. The synthesized CQDLs were characterized by using experimental techniques like UV−Vis absorption, FT-IR, Transmission Electron Microscopy (TEM), steadystate and time-resolved fluorescence spectroscopy. Results: The spectral analysis shows that the so synthesized CQDLs are spherical in shape and its diameter is around 4.2 nm. It shows the fluorescence emission maximum at 495 nm with a quantum yield of 4%. In this work the interaction between Carbon Quantum Dots (CQDLs) and an organic dye Malachite Green (MG) is studied using fluorescence spectroscopic technique under ambient pH condition (At pH 7). The quenching mechanism of CQDLs with MG was investigated using Stern-Volmer equation and time-resolved fluorescence lifetime studies. The results show that the dominant process of fluorescence quenching is attributed to Forster Resonance Energy Transfer (FRET) having a donor acceptor distance of 53 Å where CQDLs act as a donor and MG acts as an acceptor. Conclusion: This work has a consequence that CQDLs can be used as a donor species for different photo physical processes such as photovoltaic cell, dye sensitized solar cell, and also for antioxidant activity study.

Electron Raman Scattering and Raman Gain in Pyramidal Semiconductor Quantum Dots

2017 ◽  
Vol 17 (2) ◽  
pp. 1140-1148
Author(s):  
K Monsalve-Calderón ◽  
A Gil-Corrales ◽  
A.L Morales ◽  
R.L Restrepo ◽  
M. E Mora-Ramos ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Raman Scattering ◽  
Semiconductor Quantum Dots ◽  
Raman Gain

FIRST ORDER RAMAN SCATTERING FROM SEMICONDUCTOR QUANTUM DOTS

1989 ◽  
Vol 03 (08) ◽  
pp. 1167-1181 ◽  
Author(s):  
P.A.M. RODRIGUES ◽  
HILDA A. CERDEIRA ◽  
F. CERDEIRA
Keyword(s):  
Crystal Structure ◽  
Quantum Dots ◽  
Raman Spectrum ◽  
Raman Scattering ◽  
Bulk Material ◽  
Semiconductor Quantum Dots ◽  
Polycrystalline Materials ◽  
Nanometer Size ◽  
First Order ◽  
Linear Dimensions

We develop a model appropriate for describing the Raman spectrum of samples, containing a collection of semiconductor quantum dots with and without dispersion in their linear dimensions. These nanometer size crystallites are assumed to have the same atomic arrangement as that of the bulk material and to be embedded in a host material made up of a different semiconductor of the same crystal structure. The results from our calculations are compared to previous models for polycrystalline materials.

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