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

Colloidal CsPbBr 3 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 CsPbBr 3 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 (474 nm) with narrow linewidths (25 nm) 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 480 nm 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.