Kelvin probe force microscopy for perovskite solar cells

Kelvin probe force microscopy (KPFM) could identify the local work function of surface at nanoscale with high-resolution on the basis of simultaneous visualization of surface topography, which provides a unique route to in-situ study of the surface information like the composition and electronic states. Currently, as a non-destructive detection protocol, KPFM demonstrates the unique potential to probe the basic nature of perovskite materials that is extremely sensitive to water, oxygen and electron beam irradiation. This paper systematically introduces the fundamentals and working mode of KPFM, and elaborates the promising applications in perovskite solar cells for energy band structures and carrier transport dynamics, trap states, crystal phases, as well as ion migration explorations. The comprehensive understanding of such potential detection engineering may provide novel and effective approaches for unraveling the unique properties of perovskite solar cells.