Mesoscale Functional Imaging of Materials for Photovoltaics

Further global adoption of photovoltaic energy conversion technologies is contingent on sustained progress toward widespread grid-parity. For that, solar cell materials composed of microscale grains and nanoscale boundaries show the highest potential due to their large theoretical efficiency and low-cost fabrication methods. Here we outline the current challenges facing hybrid perovskites and prevalent thin-film polycrystalline materials for photovoltaics. We offer our perspective on how mesoscale functional imaging can enable a complete understanding of the physical and chemical processes restricting their performance, completing the materials science structure–properties–processing–performance tetrahedron. First, we present the key characteristics of hybrid perovskites, CdTe, CIGS, CZTS, and pc-GaAs, emphasizing their main limitations. Second, we discuss how novel imaging methods based on electron and scanning probe microscopies can be realized to provide quantitative information about the relevant parameters (figures-of-merit) that define solar cell performance, with nanoscale spatial resolution. Finally, we offer our vision for the upcoming years, wherein correlative functional microscopy will lead to a complete narrative of the electrical, optical, structural, and chemical properties of these materials, including their surface and bulk properties.