Technical: This project is designed to provide a detailed understanding of photophysics in conjugated polymers used for optoelectronic applications. Transient absorption and delayed luminescence experiments are performed on solutions and films of electroluminescent polymers to address the root cause of the decrease in fluorescence quantum yield in films, the branching ratio for recombination of charge carriers to form singlet states and the origin of magnetic field effects in organic light-emitting diodes. In donor-acceptor blends relevant to fabrication of solar cells from conjugated polymers, time-delayed field collection experiments to quantify charge photogeneration efficiency and transient absorption to ascertain whether energy transfer plays an important role in organic photovoltaics.
The research has implications for the design of materials and device structures for solar cells, optically pumped film lasers, lighting, display devices and spintronic technologies based on processable conjugated polymer materials. Graduate and undergraduate students participating in the research acquire interdisciplinary training in areas as diverse as condensed matter physics, optics, materials science, analytical chemistry and device engineering. Hands-on educational modules demonstrating how conjugated polymers can change color and enable light detection as in solar cells are developed for middle and secondary school students in collaboration with a local high school science teacher and disseminated on the Internet