Size-controlled synthesis of highly luminescent organometal halide perovskite quantum dots

Size-tunable organometal halide perovskite CH 3 NH 3 PbBr 3 quantum dots (QDs) were successfully synthesized by a simple surfactant-assisted reprecipitation technique, in which the size-tunability was realized by varying the molar ratios of methylammonium bromide (CH 3 NH 3 Br) to PbBr 2 while the total amount of octylamine (OTAm) and CH 3 NH 3 Br remained unchanged. The diameters of CH 3 NH 3 PbBr 3 QDs could be effectively tuned from 1.6 to 3.9 nm, and these QDs exhibited an obviously size-dependent optical properties , whose photoluminescence (PL) covered the spectral region from 440 to 530 nm and the emission width was 20–32 nm. The maximum absolute PL quantum yield (PLQY) was measured to be as high as approximately 80% at room temperature. A plausible formation mechanism was proposed and the quantum confinement effect was discussed based on effective mass approximation. Moreover, this synthetic approach could also be extended to prepare different halide perovskite QDs including CH 3 NH 3 PbCl x Br 3 − x and CH 3 NH 3 PbBr 3 − x I x ( x  = 1–3), which realized the color-tunability over the entire visible spectral region of 390–750 nm. The size- and compositional-tunable emission colors of organometal perovskite QDs endows them wide potential applications in next-generation optoelectronic devices.