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Showing 1 to 20 of 59 for “"transient absorption spectroscopy"”.
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Ultrafast photophysics of transition metal coordination complexes studied with femtosecond extreme ultraviolet transient absorption spectroscopy
… using a homebuilt extreme ultraviolet (XUV) transient absorption apparatus. XUV photons are produced via high-harmonic generation, allowing M-edge XANES measurements to be performed as an in-lab technique. This developing technique is coupled with semi-empirical ligand field multiplet (LFM) …
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Nanoparticle-nanoparticle interactions and light-matter interaction studied by simulated absorption spectroscopy
… efficient tight-binding calculations, the absorption spectra of homodimer and heterodimer nanoparticles are explored. Then, plasmon-induced excitation energy transfer is simulated with an attosecond time step up to investigate processes occurring on the picosecond dynamics time scale. …
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The Photochemistry of Beta-Naphthoyl Azide and 4-Acetylphenoxycarbonyl Azide: The Chemical and Physical Properties of Acylnitrenes
… optical, electron spin resonance, and transient absorption spectroscopy as well as by traditional chemical trapping techniques.
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Charge recombination in organic small-molecule solar cells by Jiye Lee.
… loss needs to be minimized. First, we perform transient absorption spectroscopy to study the charge recombination dynamics of thin film bulk heterojunction of the archetype organic solar cell molecules, copper phthalocyanine (CuPC) and 3,4,9,10-perylenetetracarboxylic bis-benzimidazole (PTCBI). …
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Photolysis of (Halomethyl)naphthalenes: An Investigation of the Heterolysis and Homolysis of Carbon-Halogen Bonds in (Arylmethyl)halides
… and quenching experiments, and the technique of transient absorption spectroscopy. Evidence is presented for three modes of heterolytic bond cleavage. The first originates from an excited singlet state, and may be direct or may involve an exciplex formed during sensitization. The second mode is …
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OPTICAL PROPERTIES OF 2D TRANSITION METAL DICHALCOGENIDES ENHANCED BY PLASMONIC NANOSTRUCTURES
… conversion in MoS2 on graphene by transient absorption spectroscopy. These interesting phenomena of PL, SHG and photoelectron originating from light-matter interaction in TMDCs were systematically investigated in this thesis, facilitating the integrating of these materials in …
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Overcoming Efficiency Limits in Photovoltaic Devices
… and the decision was taken to move to ultrafast spectroscopy. In examining quantum dot films using picosecond transient absorption spectroscopy, we found clear signatures of carrier multiplication occurring in films of dots synthesis here. We also found that some of our results were at odds with …
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Ultrafast Optical Spectroscopy Techniques applied to colloidal nanocrystals
… my experimental work based on ultrafast optical spectroscopy techniques applied to colloidal nanocrystals. Colloidal semiconductor nanocrystals in recent years have attracted a lot of attention in particular in optoelectronic applications, because they present unique optical, electronic and …
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A Study of Reactive Intermediates Generated by One-Electron Transfers (Diazoalkane, Cieel, Chemiluminescence, Carbene, Peroxide)
… (DCN) by 1 was found by nanosecond transient absorption spectroscopy to generate DCN('-) and another short-lived species whose (lamda)(,max) occurs at ca. 520 nm. This absorption is tentatively assigned to 1('+).
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Studies on Anthracene Tagged Oligonucleotides
… UV melting point studies, fluorescence and CD spectroscopy in order to understand the effect of varying base pairs and introducing mismatches. Certain duplexes were then studied in greater depth using transient absorption spectroscopy, to probe the formation of electron transfer intermediates …
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Synthesis and Photophysics of Varied Substituted DPNDs for Potential PDT Applications
… chromophores. Steady-state and time-resolved absorption and emission studies suggest that the three DPND chromophores exhibit longer excited-state lifetimes and stronger triplet signatures in non-polar methylcyclohexane (MCH) solvent. Conversely, in polar 50% (v/v) DCM:EtOH, the excited states …
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Photochemical reductive elimination of halogen from transition metal complexes
… require a substantial concentration of transient photointermediates for signal to be observed. These targets spurred the development of a number of late-metal homo- and heterobimetallic complexes which undergo highly efficient halogen elimination, as well as the first reports of …
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Ultrafast Ionisation Dynamics Induced by Short Proton Pulses
… TARANIS laser at Queen’s University Belfast of transient absorption spectroscopy of dynamics induced by bursts of radiation, predominantly ions, from high-power laser-solid interactions. The absolute measurement of proton bursts as short as 3.7 ± 0.7 psis reported, enabled by the ultra fast …
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Spectroscopic Studies on the Impact of Defects in Hybrid Organic-Inorganic Perovskites on Charge Carrier Dynamics and Photovoltaic Device Performance
… this characterization, along with time-resolved spectroscopy, to better understand the influence of carrier dynamics on solar cell device performance. We observed that a decrease in device fill factor corresponded to an increase in trap state density and a change in the trapping rate constant, …
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Photophysical transformations in molecules studied by ultrafast multi-pulse spectroscopy /
… of three different systems by the means of transient absorption spectroscopy. First two chapters are dedicated to the theoretical background, the description of the objects of the study and the experimental tools used. The following three chapters correspond to three different systems …
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Molekulių fotofizikinių virsmų tyrimas ultrasparčiosios daugiaimpulsės spektroskopijos metodais /
… of three different systems by the means of transient absorption spectroscopy. First two chapters are dedicated to the theoretical background, the description of the objects of the study and the experimental tools used. The following three chapters correspond to three different systems …
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Visible light-induced pH control and its applications
… based on experimentally defined parameters. Transient absorption spectroscopy was used to explore the influence of the protonation state of the merocyanine form (MCH vs MC) on the photoswitching efficiency. A python model is developed to describe the pH- recovery in the dark. Chapter 3 …
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Photochemistry, photophysics and spectroscopy of redox states of flavins relevant to photoactive flavoproteins
… FADH● and FAD●- with the visible to mid-IR transient absorption spectroscopy. Ground and excited state frequencies of the characteristic carbonyl modes are observed and assigned with the aid of DFT calculations. Moreover, the stable neutral radical flavin has been prepared for study in …
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The Influence of Inner-Sphere Reorganization on Rates of Interfacial Electron Transfer in Transition Metal-Based Redox Electrolytes
… regeneration rates are monitored using transient absorption spectroscopy (TAS) to discern the optimal E1/2 values in this class of complexes while density functional theory is employed to calculate the reorganization energy of each species. By implementing these promising electrolytes …
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Time-Resolved Studies of Aryl Carbenes
Picosecond transient absorption spectroscopy (using a Nd:YAG laser with 355 nm excitation and 440 nm to 640 nm probe) was used to study three aryl carbenes generated by photolysis of their parent diazo compounds in fluid solution. Irradiation of 9-diazofluorene generates a transient with an …
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