Photoemission Spectroscopy of Solar Cell Materials

This chapter focuses on the application of X-ray photoemission spectroscopy (XPS) to the characterisation of solar cell materials. XPS provides essential insights into the electronic structure, chemical composition, interface properties, and band alignments of photovoltaic (PV) materials, aiding in the optimisation of solar cell efficiency. The chapter covers various solar cell technologies, including thin-film, perovskite, and organic photovoltaics, highlighting how XPS can be utilised to measure work functions, ionisation potentials, and band alignments. Practical methodologies for determining band alignment at PV material interfaces are discussed, illustrated by detailed examples from tin sulfides and perovskite materials. The integration of XPS with complementary techniques like density functional theory (DFT) and inverse photoemission spectroscopy (IPES) demonstrates its critical role in advancing the understanding and performance of diverse solar cell architectures.