Physicochemical processes in evaporation-based perovskite LEDs.

Evaporation-based manufacturing of halide perovskite light-emitting diodes has garnered increasing attention as a promising alternative for addressing issues with conventional solvent-based processing methodologies. Similar to existing organic light-emitting diode processing infrastructures, evaporation-based processing uses vapour-phase precursor transport and deposition, enabling solvent-free synthesis, precise nanoscale thickness control and enhanced patterning resolution. The physicochemical mechanism of such vacuum-based deposition and growth processes, which is radically different from that of solution-based processes, involves complex thermodynamic and kinetic factors regarding solid-vapour-solid transitions. This imposes much more stringent requirements for deposition environment, mandating concurrent advances in the fundamental understanding of evaporation and growth phenomena, as well as deposition equipment design. In this Perspective, we present a chemistry-driven framework for incorporating fundamental physicochemical principles into evaporation-based processing, with the aim of guiding reproducible and scalable perovskite light-emitting diode deposition system.