Identification of both preequilibrium and diffusion limits for reaction of singlet oxygen, O2(1.DELTA.g), with both physical and chemical quenchers: variable-temperature, time-resolved infrared luminescence studies

1988 ◽  
Vol 110 (24) ◽  
pp. 8053-8059 ◽  
Author(s):  
A. A. Gorman ◽  
I. Hamblett ◽  
C. Lambert ◽  
B. Spencer ◽  
M. C. Standen
Keyword(s):  
Singlet Oxygen ◽  
Variable Temperature ◽  
Time Resolved ◽  
Infrared Luminescence ◽  
Diffusion Limits ◽  
Physical And Chemical ◽  
Temperature Time ◽  
And Diffusion

Triplet harvesting in luminescent Cu(i) complexes by the thermally activated luminescence transition mechanism: impact of the molecular structure

2017 ◽  
Vol 5 (18) ◽  
pp. 4488-4494 ◽  
Author(s):  
Z. C. Su ◽  
C. C. Zheng ◽  
G. Cheng ◽  
C.-M. Che ◽  
S. J. Xu
Keyword(s):  
Molecular Structure ◽  
Variable Temperature ◽  
Delayed Fluorescence ◽  
Time Resolved ◽  
Thermally Induced ◽  
Thermally Activated ◽  
Transition Mechanism ◽  
Time Resolved Photoluminescence ◽  
Temperature Time ◽  
Triplet Harvesting

Thermally induced transition from ordinary phosphorescence to delayed fluorescence in two kinds of luminescent copper(i) complexes is comprehensively investigated by using variable-temperature time-integrated and time-resolved photoluminescence measurements as well as model analysis.

scholarly journals Photophysical Properties of Protoporphyrin IX, Pyropheophorbide-a, and Photofrin® in Different Conditions

2021 ◽  
Vol 14 (2) ◽  
pp. 138
Author(s):  
Bauyrzhan Myrzakhmetov ◽  
Philippe Arnoux ◽  
Serge Mordon ◽  
Samir Acherar ◽  
Irina Tsoy ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Photophysical Properties ◽  
Protoporphyrin Ix ◽  
Fluorescence Emission ◽  
Solvent Polarity ◽  
Visible Absorption ◽  
Light Dosimetry ◽  
Time Resolved ◽  
Pyropheophorbide A ◽  
Influence Of Solvent

Photodynamic therapy (PDT) is an innovative treatment of malignant or diseased tissues. The effectiveness of PDT depends on light dosimetry, oxygen availability, and properties of the photosensitizer (PS). Depending on the medium, photophysical properties of the PS can change leading to increase or decrease in fluorescence emission and formation of reactive oxygen species (ROS) especially singlet oxygen (1O2). In this study, the influence of solvent polarity, viscosity, concentration, temperature, and pH medium on the photophysical properties of protoporphyrin IX, pyropheophorbide-a, and Photofrin® were investigated by UV-visible absorption, fluorescence emission, singlet oxygen emission, and time-resolved fluorescence spectroscopies.

scholarly journals Photoreactivity of Hair Melanin from Different Skin Phototypes—Contribution of Melanin Subunits to the Pigments Photoreactive Properties

2021 ◽  
Vol 22 (9) ◽  
pp. 4465
Author(s):  
Krystian Mokrzynski ◽  
Shosuke Ito ◽  
Kazumasa Wakamatsu ◽  
Theodore G. Camenish ◽  
Tadeusz Sarna ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Singlet Oxygen ◽  
Near Infrared ◽  
Paramagnetic Resonance ◽  
Time Resolved ◽  
W Band ◽  
Epr Oximetry ◽  
X Band ◽  
Hair Samples ◽  
Electron Paramagnetic

Photoreactivity of melanin has become a major focus of research due to the postulated involvement of the pigment in UVA-induced melanoma. However, most of the hitherto studies were carried out using synthetic melanin models. Thus, photoreactivity of natural melanins is yet to be systematically analyzed. Here, we examined the photoreactive properties of natural melanins isolated from hair samples obtained from donors of different skin phototypes (I, II, III, and V). X-band and W-band electron paramagnetic resonance (EPR) spectroscopy was used to examine the paramagnetic properties of the pigments. Alkaline hydrogen peroxide degradation and hydroiodic acid hydrolysis were used to determine the chemical composition of the melanins. EPR oximetry and spin trapping were used to examine the oxygen photoconsumption and photo-induced formation of superoxide anion, and time-resolved near infrared phosphorescence was employed to determine the singlet oxygen photogeneration by the melanins. The efficiency of superoxide and singlet oxygen photogeneration was related to the chemical composition of the studied melanins. Melanins from blond and chestnut hair (phototypes II and III) exhibited highest photoreactivity of all examined pigments. Moreover, melanins of these phototypes showed highest quantum efficiency of singlet oxygen photogeneration at 332 nm and 365 nm supporting the postulate of the pigment contribution in UVA-induced melanoma.

scholarly journals Photooxidation and Photobleaching of Single CdSe/ZnS Quantum Dots Probed by Room-Temperature Time-Resolved Spectroscopy

2001 ◽  
Vol 105 (35) ◽  
pp. 8281-8284 ◽  
Author(s):  
Wilfried G. J. H. M. van Sark ◽  
Patrick L. T. M. Frederix ◽  
Dave J. Van den Heuvel ◽  
Hans C. Gerritsen ◽  
Ageeth A. Bol ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Room Temperature ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Temperature Time

scholarly journals Study of Singlet Oxygen Dynamics on Silicon Polymer Matrix

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Jeong-Wook Hwang ◽  
Seung-Jin Jung ◽  
Il Heo ◽  
Hyun-A Son ◽  
Jong-Ho Kim ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Detailed Analysis ◽  
Polymer Film ◽  
Polymer Matrix ◽  
Time Resolved ◽  
Surface Component ◽  
Component C ◽  
Oxygen Dynamics ◽  
Silicone Polymer

We report a detailed analysis of singlet oxygen generated from the photofunctional polymer film (PFPF) matrix which is the silicone polymer film (PDMS) embedded with a photosensitizer. Activation and deactivation dynamics of singlet oxygen generated from PFPFs were investigated with time-resolved phosphorescence spectroscopy. The singlet oxygen generated from PFPFs was dissipated into three different regions of the polymer matrix; the inside (component A), the surface (component B), and the outside (component C). According to the deactivation dynamics of singlet oxygen in the polymer matrix, the components B and C are expected to be more important for various applications.

Comparative Study of Photocarrier Dynamics in CVD-deposited CuWO4, CuO, and WO3 Thin Films for Photoelectrocatalysis

2020 ◽  
Vol 234 (4) ◽  
pp. 699-717
Author(s):  
James Hirst ◽  
Sönke Müller ◽  
Daniel Peeters ◽  
Alexander Sadlo ◽  
Lukas Mai ◽  
...  
Keyword(s):  
Thin Films ◽  
Carrier Mobility ◽  
Carrier Transport ◽  
Terahertz Spectroscopy ◽  
Chemical Vapor ◽  
Photoelectrochemical Cells ◽  
Time Resolved ◽  
And Diffusion ◽  
Wo3 Thin Films ◽  
Carrier Transport Properties

AbstractThe temporal evolution of photogenerated carriers in CuWO4, CuO and WO3 thin films deposited via a direct chemical vapor deposition approach was studied using time-resolved microwave conductivity and terahertz spectroscopy to obtain the photocarrier lifetime, mobility and diffusion length. The carrier transport properties of the films prepared by varying the copper-to-tungsten stoichiometry were compared and the results related to the performance of the compositions built into respective photoelectrochemical cells. Superior carrier mobility was observed for CuWO4 under frontside illumination.

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