Photoelectrochemical cell design, efficiency, definitions, standards, and protocols

This chapter serves as a reference for the basic design, testing, and efficiency definitions for photoelectrochemical (PEC) water-splitting cells. In particular, design principles and standards are given for PEC cells that utilize thin film semiconductor photoelectrodes, whose development and technological progress far exceeds those of other materials approaches. Different PEC device designs and operating principles are briefly discussed, which can be used for different material arrangements, architectures, and possible cell designs. In addition, practical techniques for benchmarking are presented to measure both device efficiencies and materials performance as a function of optical and electronic energy input. Standard protocols for these measurement techniques and necessary standardized equipment are also presented in the context of the fundamental information they can relate between performance and material/device limitations. Overall, a general overview of PEC cell requirements is given along with standard measurement techniques and efficiency definitions.