ABSTRACT
Figure 1.1 Schematic sketch for two commonly studied devices: OPV and OLED. The processes that are of fundamental interested are listed.
As shown in Fig. 1.1, in OLED, the electrons or holes are drifted across a film of organic or polymeric semiconducting material, creating either an excited state or an accumulated charge at the interface, and further electrooptically useful results are then generated. In collecting solar energy with an OPV cell, the optically
excited exciton migrates to the interface of an electron-and a holetransporting material where charge separation (CS) takes place. The basic principle of dye-sensitized solar cells (DSSCs) is similar, where the sunlight is absorbed by the dye, and subsequent charge injection takes place at the dye-TiO2interface. With a CS, the electrons and holes are generated, and subsequently transported in the electronand hole-transporting materials. Charge recombination (CR) can also take place at the interface, contributing to a loss of efficiency.
