p-Type Molecular Materials for Organic Solar Cells
The search for a clean, renewable source of energy as a replacement for fossil fuels has been at the forefront of scientific, economic and political research for the past few decades. Of the commonly investigated techniques, one strong contender that fits this role extremely well is solar power. The ability to harvest energy from sunlight incident on the Earth’s surface in an efficient and cost-effective manner would alleviate the global energy crisis with relative ease – more energy reaches the Earth from the Sun in one hour than all the energy consumed on the planet in an entire year. Progress has been both fast and expansive, with a large number of research groups across the globe finely tuning and improving solar-harvesting technology. Organic solar cells show huge promise for future energy-harvesting because they allow very low-cost production through the use of low-temperature fabrication techniques, such as roll-to-roll processing or inkjet printing. Organic solar cell materials can also be made to be flexible and semi-transparent and are extremely lightweight compared with the current market-leading silicon-based alternatives. This chapter aims to give a concise overview of some of the progress made to date, with attention focused on prepared and tested state-of-the-art, high-performance materials.