Department of Chemical EngineeringColloidal semiconductor nanocrystals, also known as nanocrystal quantum dots(QDs), are being studied intensively as future optoelectronic materials due to its solution processing and outstanding optical properties. Among them, perovskite quantum dots(PeQDs) have a wide emission range from near-infrared to ultraviolet by controlling its composition, and are highly luminescent with narrow FWHM by easier synthesize process. Therefore, perovskite nanocrystals are receiving attention as a high-quality optoelectric device material.
However, there is a drop of quantum yield at specific composition includes chloride anion, which are covering blue to ultraviolet emission range. Due to the drop of quantum yield, high-quality blue LED with perovskite still not reported.
In this work, I report the highly luminescent chlorine-free blue perovskite nanoplatelets(PeNPLs) as pure bromide halide composition, which was synthesized by supporting of saturated amine ligand. The thickness of PeNPLs was controlled by reaction parameters such as reaction time and reaction temperature. Also, thickness homogeneity was secured by ligand assisted solubility adjustment method after synthesis. Through this two-step thickness control, photoluminescence properties of the synthesized PeNPLs could be easily concentrated on specific wavelength emission while the full width half maximum (FWHM) could be decreased under 22 nm. Furthermore, the time dependent stability of nanoplatelets increase through close-packed ligands which are less steric hindered. Lastly, blue light emitting diodes (LED) with surface-treated perovskite nanoplatelets could have higher efficiency than mixed-halide perovskite nanocrystal. It was possible by emitting material???s property improvement and close-stacked nanoplatelets arrange. I strongly believe that this work would be the basic approach of perovskite nanoplatelet device.ope
