Room‐Temperature Synthesis of Strongly Confined Lead Halide Perovskite Quantum Dots

Colloidal quantum dots (QDs) are promising for light‐emitting applications, but their synthesis under ambient conditions remains challenging. Here we present a rapid, room‐temperature (RT) method that produces highly stable QDs within minutes using the zwitterionic ligand 2‐ammonioethyl 2‐octyl‐1‐dodecyl phosphate (OD‐PEA). The strong binding of OD‐PEA enables precise size control and effective passivation, yielding blue‐emitting QDs () with narrow linewidths () and high photoluminescence quantum yields (up to 86 %). The QDs retain their optical quality for months in air and offer tunable emission from blue–cyan through ligand concentration, and from ultraviolet to deep red via halide exchange. A proof‐of‐concept perovskite light‐emitting diode (PeLED) fabricated from these QDs exhibits appreciable electroluminescence (EL) at with a low turn‐on voltage. This work establishes a simple and scalable strategy for producing stable, strongly confined perovskite QDs, advancing their potential for next‐generation optoelectronic and photonic technologies.