Magnetic, Optical and Dielectric Effects on Photovoltaic Processes in Organic Solar Cells

Organic bulk heterojunction photovoltaics have attracted extensive attention during the past decade due to the global energy crisis, and it had been nominated as one of the most promising substitution for the next generation of green energy. Organic Photovoltaics, also named as “plastic solar cells”, have many advantages including super-low cost, flexibility, and compatibility with the ink printing fabrication technique, etc. Although the photovoltaic efficiency of the organic bulk heterojunction is still not as high as that of the inorganic ones, its great potential makes it the most promising solar cells in the future. In this dissertation, Chapter 1 presents a basic introduction to the concepts of conjugated polymers, the widely utilized materials in photovoltaic devices, and the fundamental device physics. Meanwhile, some basic spintronics was also discussed in this chapter. Finally, the peer publications review is briefly discussed in order to cover the academic progress in this field. Chapter 2 and Chapter 3 systematically study the origin of open circuit voltage in organic photovoltaics. Chapter 4 and Chapter 5 study the magnetic field effect on photocurrent change of bulk heterojunction and double layer photovoltaics, respectively. Chapter 6 focuses on the “intra-molecular” interaction effect on internal photovoltaic processes in new low band gap materials based on magnetic field effect and photoassisted dielectric response techniques. Finally, Chapter 7 gives a short conclusion for the entire dissertation.