Chapter 4: Blocking Layers for Controlling Directional Charge Transport in Dye-sensitized Photoelectrochemical Cells

Managing charge transfer is a fundamental challenge in the development of functional devices for energy conversion and storage. Thin oxide blocking layers can function to rectify the flow of charge, permitting the movement of charge in the desired direction and retarding movement in the opposite direction. This is accomplished with either the oxide layer functioning as a tunneling barrier or as part of an energy cascade. Although broadly applicable to many technologies, the use of thin oxide layers to control charge transfer has attracted considerable interest in the area of dye-sensitized energy conversion systems and much of our fundamental understanding comes via these technologies. This chapter explores how electronic structure develops in these thin oxide layers, how they can work to inhibit undesired electron transfer events, and how that translates into device performance.