The C545T is a green dopant material that is widely used in the organic light emitting diode. The effect of acidity on the UV and fluorescence spectra of C545T in aqueous acidic solutions and in the solid state has been studied. In acid-free or at low acid concentration solutions and films, only an emission at 510nm is observed. Increasing the acid concentration up to a value that depends on the solvent causes a new emission at 570nm and is assigned to emission from a protonated from. The acidic solvents we used in this study are oxalic acid and benzyl sulfonic acid. The energy transfer from unprotonated species to protonated species has been observed. We also use a simple model to calculate the efficiency of energy transfer.

Thesis (Ph.D.)--University of Wyoming, 2007. / Title from PDF title page (viewed on June 22, 2009). Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1963.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

"The photophysics of several bichromophoric dipeptide model compounds and two trichromophoric 15-residue peptides have been studied by a combination of absorption, fluorescence, phosphorescence and laser flash photolysis. Intramolecular singlet-singlet energy transfer (SSET) occurs efficiently within these systems. Trichromophore 14 undergoes intramolecular SSET from the central chromophore to the termini, kSSET = 5.8 x109 s-1 , with a five fold increase over 13, kSSET = 1.1 x 109 s-1 . Evaluation of SSET mechanisms via the Förster treatment and molecular modeling indicates that the dipole-induced dipole mechanism is sufficient to account for the observed SSET. However, given the close distances of the chromophores (~10 Å), an electron exchange mechanism can not be ruled out. Low-temperature phosphorescence in 1:1 methanol/ethanol and room-temperature laser flash photolysis in acetonitrile results indicate that intramolecular triplet-triplet energy transfer (TTET) is efficient in dipeptides 7,9-12 and proceeds with a rate constant of kTTET > 5 x 10 8 s-1. The occurrence of TTET in dipeptide 8, (biphenyl-naphthalene), could not be confirmed due to the fact that SSET from biphenyl to the naphthalene moiety was 26 times greater than kISC. Thus nearly all absorbed light was funneled directly the to the singlet manifold of the naphthalene moiety. TTET in the trichromophores could not be fully evaluated due to their low solubility. However, it is shown from 77°K experiments that kTTET is at least 2.2 x 102 and 2.6 x 102 s-1 for 13 and 14 respectively."

Understanding how the transmission of energy between the providers (such as nuclear power stations, renewable resources, or any type of supplying entity) and the consumers (such as factories, homes, or any type of demanding entity) depends on the structure of the inter-connections between them and on their dynamical be- haviour, is of paramount importance for the design of power-grid systems that are resilient to failures, e.g., failures due to structural modifications or energy fluctu- ations. In this thesis, we derive the implicit relationship between structure and behaviour that flow and power networks have, namely, the mathematical principles behind the transmission of energy in complex networks. From our novel derivations, we determine exact and approximate strategies to create self-controlled and stable systems (i.e., resilient to failures without the need for external controllers) that have an optimal (i.e., with less cost and power dissipation) and smart (i.e., allowing the decentralisation of large power-stations to smaller fluctuating renewable resources) energy distribution. Moreover, not only we achieve analytical solutions for problems that usually require a numerical analysis, but we also propose a change in the analy- sis view-point of complex systems, namely, systems composed of many dynamically interacting units forming a network. We show that in order to explain the emer- gent behaviour in these systems, instead of focusing on the network structure of the interactions, we should focus on the functional form of the interactions. In particu- lar, we derive a general framework to study the existence and stability of emergent collective behaviour in networks of interacting phase-oscillators, namely, the math- ematical principles behind the synchronisation in complex networks. The numerous breakthrough results in this thesis are expected to be of aid for engineers to design smarter and more resilient power-grid systems, as well as to scientists dealing with emergence of collective behaviour in complex systems.

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