Basic Principles of Modern Organic Solar Cells

Abstract

In 2018, solar cells supplied 2% of the global electricity demand. This must be increased over 20%; therefore, organic solar cells with inherent cost-reducing abilities are indispensable. In this chapter, the basic principles of modern organic solar cells are summarized. Exciton, donor/acceptor sensitization, exciton diffusion, blended junction, designed route formation, and π-π  stacking orientation are discussed regarding the photocurrent, while HOMO-LUMO gap tuning and the non-radiative recombination loss are examined regarding the photovoltage. The tandem cells as well as junction fabrication by doping alone are considered for cell design. Historically, blend and tandem strategies have continuously enhanced efficiencies. The efficiency of organic solar cells, which continues to progressively increase, has risen steadily at the rate of 1% per year and has reached 17.3% in 2020. Organic solar cells, with their fascinating advantages, have sufficient potential to engender the next-generation solar cells.