Luminescent organic materials and their application in solar technologies

Abstract

In Chapter 1, we begin with a brief introduction to the principles of photoluminescence from organic materials and the luminescent solar concentrator (LSC). In Chapter 2, we describe the red phosphorescence from a class of four structurally simple benzo[2,1,3]thiadiazoles in cyclohexane. The photophysical properties of these molecules are presented along with a computational analysis of their electronic excited states. Chapter 3 discusses the development and evaluation of an efficient, low-reabsorbing luminescent solar concentrator (LSC) that employs two 7r-conjugated polymers as surrogate absorbers for a minority amount of the perylene bisimide Lumogen F Red 305. We developed a small LSC wherein a mixture of the two polymers act as both the host layer and antennae for a 1.5 wt% loading of Lumogen F Red 305. A Monte Carlo simulation predicts the LSC to possess high edge optical efficiencies and concentration factors on larger, commercially relevant scales. Efforts toward an efficient energy transfer cascade between three 7r-conjugated polymers in poly(methyl methacrylate) (PMMA) are also discussed. Chapter 4 describes an LSC that utilizes a deoxygenated liquid perfluorocarbon (PFC) as the host for a strongly fluorescent perfluoroalkylated thieno[3,4-b]pyrazine between two slabs of PMMA. In the event the luminophore photodegrades after prolonged exposure to sunlight, the luminescent layer can be easily replaced with new solution. Additionally, we demonstrate that the relatively low refractive indices of PFCs causes the luminophore's emission to efficiently couple into the PMMA slabs, where no reabsorption processes can undermine the efficiency of the LSC. In Chapter 5, we present progress toward iptycene-functionalized naphthazarins intended for the development of solid-state luminescent or redox-active metallopolymers.