Impedance characteristics of hybrid organometal halide perovskite solar cells

Abstract

This chapter describes the application of impedance spectroscopy and an array of related experimental techniques used to understand the operation principles of lead halide perovskite solar cells and their related materials. The main topic of the chapter is the identification of capacitances and their origin, which is related to ion accumulation, electron accumulation, or a combination of both. In addition to impedance spectroscopy, we examine a number of charging or time transient techniques that are performed by a voltage step or continuous cycling, including capacitance-voltage characterization and Kelvin probe force microscopy. The interpretation is carried out using several experimental modifications such as application of different contacts, sample thickness, and temperature. The relationship of hysteresis to capacitance is also addressed, as well as the degradation at contacts by ionic accumulation and reaction.