Ligand-Mediated Synthesis of CsPbI3 Quantum Dots with Strong Quantum Confinement: Implications for Red Emission in Displays

Due to their unique photoelectric properties, perovskite quantum dots (PQDs) are of growing interest. The preparation of pure red-emitting perovskite materials is a key step to achieve a full-color display. To date, the precise growth mechanism of CsPbI3 QDs under thermodynamic equilibrium control remains unexplored. We reveal the regulation of reaction parameters on the nucleation and confined growth of pure-red CsPbI3 strongly confined quantum dots (SQDs). Key intermediate perovskite nanoclusters in the formation of SQDs were revealed, and the effects of the ligands and temperature on their growth pathway were systematically investigated. By adjusting the reaction parameters, such as the ligand concentration, ratio, and temperature, control over size, size distribution, and phase (CsPbI3 or Cs4PbI6) can be achieved. Furthermore, our findings shed light on the solubility of PbI2 in this iodine-rich synthesis system and are suggested to aid the understanding of ligand-mediated size and phase control of CsPbI3 QDs.