Kelvin Probe Force Microscopy Characterization of Organic and Hybrid Perovskite Solar Cells

Abstract

Nowadays, solution processed solar cells based on organic and hybrid-perovskite semi-conductors are serious competitors for silicon-based and inorganic photovoltaic technologies in terms of production costs, performance to weight ratio, flexibility, and easy manufacturing. Since the beginning of this century, the power conversion efficiency (PCE) values of polymer solar cells have continuously increased, and now exceed ten percent. More recently, following the development of dye-sensitized solar cells, lead-halide perovskite based devices with various architectures have been developed leading to PCE exceeding twenty percent. The goal of this chapter is to show how KPFM can contribute to further improve the performances of these solution-processed photovoltaic devices, by gaining a deeper insight in the local mechanisms governing the charge carrier generation, recombination, transport, and extraction at the electrodes. This chapter will focus more specifically on KPFM investigations of the surface potential and surface photo-voltage of organic donor-acceptor interfaces and polycrystalline lead halide perovskites in relation with the sample morphology and structural defects at the mesoscopic and nanometer scales, cross sectional KPFM investigations, and time-resolved measurements of the charge dynamics by KPFM under frequency modulated illumination.