How Light-Harvesting and Energy-Transfer Processes Are Modified Under Different Light Conditions: STUDIES by Time-Resolved Fluorescence Spectroscopy

2017 ◽  
pp. 169-184
Author(s):  
Seiji Akimoto ◽  
Makio Yokono
Keyword(s):  
Energy Transfer ◽  
Fluorescence Spectroscopy ◽  
Light Harvesting ◽  
Light Conditions ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Transfer Processes

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.

Polypeptides with pendant porphyrins of defined sequence of chromophores: towards artificial photosynthetic systems

2008 ◽  
Vol 12 (12) ◽  
pp. 1232-1241 ◽  
Author(s):  
Farid Aziat ◽  
Régis Rein ◽  
Jorge Peón ◽  
Ernesto Rivera ◽  
Nathalie Solladié
Keyword(s):  
Energy Transfer ◽  
Excited State ◽  
Amino Acid ◽  
Fluorescence Spectroscopy ◽  
Photophysical Properties ◽  
Free Base ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Absorption And Fluorescence Spectroscopy ◽  
Artificial Photosynthetic

In this paper we now report our ongoing progress in the preparation of artificial photosynthetic systems through the preparation of light harvesting multi-porphyrins. A tetramer, constituted of a central dipeptide functionalized by two free-base porphyrins and surrounded by one amino-acid bearing a pendant Zn ( II ) porphyrin on each side, has been chosen. The optical and photophysical properties of this tetramer have been studied by absorption and fluorescence spectroscopy. In addition, the energy transfer phenomenon has been studied and monitored by femtosecond time-resolved fluorescence. Our results indicate that the excited state dynamics redounding in the excitation being localized in the inner free-base porphyrins takes place in the time scale of approximately 1 ps.

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