Supramolecular control in hybrid perovskite photovoltaics

Hybrid organic–inorganic metal halide perovskites have become one of the leading thin-film semiconductors for renewable energy conversion in photovoltaics. These soft ionic materials feature remarkable optoelectronic properties and solar-to-electric power conversion efficiencies; however, they are unstable under operating conditions, such as against external environmental factors (i.e. oxygen and moisture) and internal ion migration that is accelerated upon temperature changes, voltage bias, and light. To address this challenge, various strategies have been developed to stabilise hybrid perovskite materials and their photovoltaic devices, which rely on compositional, interfacial, and device engineering. In particular, controlling their supramolecular assemblies with the organic components by tailoring various noncovalent interactions, such as hydrogen bonding, halogen bonding, van der Waals or π-based interactions, has been pertinent. This involves the use of molecular modulators that assemble at the interface with hybrid perovskites, as well as organic spacer cations templating lower-dimensional perovskite frameworks with enhanced operational stabilities. This chapter provides insights into emerging supramolecular strategies for stabilising hybrid perovskite materials and devices, advancing their applications in photovoltaics.