Challenges and opportunities in IR nanospectroscopy measurements of energy materials

The performance of functional materials and specifically energy-related functional materials, such as fuel cells, solar cells, batteries and catalysts depends on the their local, nanoscale properties. However, heterogeneities in the phase, structure and composition of these functional materials makes it difficult to directly monitor and identify the influence of local physicochemical parameters on their global functionality. In this review we will discuss recent developments in the field of IR nanospectroscopy that enables the extraction of detailed chemical information at the nanoscale and the identification of nanoscale properties that influence the global performances of functional materials. Specifically, we will discuss the ways by which IR nanospectroscopy techniques, namely photo thermal induced resonance (PTIR) and scattering scanning near-field optical microscopy (s-SNOM), are utilized in order to identify nanoscale properties and their influence on the functionality of halide-perovskite solar cells and catalytic nanoparticles. In the last part of this review we will address the technical challenges and opportunities in expanding the scope of IR nanospectroscopy measurements into the field of electrochemistry-based functional materials.