From molecular oligomers to supramolecular gels: Photophysics of conjugated metal-organic systems

In this dissertation, several series of platinum acetylide oligomers have been prepared and studied by photophysical methods. The motivation for the research stems from direct opto-electronic applications that platinum acetylide materials may be used for, as well as from a more fundamental need to gain a better understanding on the triplet excited state in conjugated systems.; First, platinum acetylide oligomers containing energy traps were prepared in order to investigate their effect on the triplet excited state. Second, the delocalization of charge carriers (radical anions and cations) was studied to determine the charge transport properties of these materials and the effect of platinum on the charge carriers. Third, a series of platinum acetylide oligomer was designed to self-assemble in solution with the goal of determining the consequences of aggregation on the triplet excited state. The goal of this work was to gain an insight into the dynamics of the triplet excited state in conjugated systems.; The most significant findings of the study are as follows: (i) although more localized than the singlet exciton, the triplet exciton is also sensitive to the presence of energy traps, which can have a significant impact on the photophysical properties of the materials; (ii) charge carriers are relatively localized on the oligomer chain and the estimated delocalization of the radical cation is no more than two repeat units; (iii) the consequences of aggregation on the triplet excited state may be very limited or relatively important, depending on the mode of aggregation.