A Facile, Low Temperature and Low-Waste Route to FAPbI3 Perovskite Nanocrystals

Lead halide perovskite nanocrystals (NCs) have emerged as versatile materials for optoelectronics, offering high fluorescence quantum yield, wide bandgap tunability, and easy solution processability. Among these, FAPbI3 NCs (FA = formamidinium) have gained significant attention for applications in photovoltaic and NIR emitting LEDs, due to their ideal narrow band gap. However, the prevailing synthetic method - hot injection - presents significant barriers to industrialization, due to the requirement for high reaction temperatures, inert atmosphere, and rapid quenching (typically within seconds of injection), limiting the scalability of the process. In this work, we present a low-energy-input, facile protocol for the preparation of phase-pure FAPbI3 nanocrystals that overcomes these technical hurdles. By careful optimization of synthetic conditions, we achieved a synthetic method that uses only low-boiling-point solvents with reduced toxicity, operates at both mild heating and room temperature, and eliminates the need for an inert atmosphere, all of which are features relevant in sight of industrialization. Beyond the synthesis itself, we also demonstrate the potential sustainability of the method by successfully recycling synthetic wastes (solvents and lead salts) for subsequent FAPbI3 nanocrystal synthesis, thus showing that our approach could significantly reduce the environmental footprint and resource depletion associated with perovskite nanocrystals production and further corroborating the potential of this protocol for the development of NCs based technologies.