Ligand Assisted Control of Photoluminescence in Organometal Perovskite Nanocrystals

Organometal perovskite nanocrystals have shown remarkable properties not only in photovoltaics, but also in light-emitting devices. In this work colloidal nanocrystals of organometal perovskite CH3NH3PbBr3 (MAPBr) with effective visible photoluminescence were synthesized by the ligand assisted reprecipitation method. The studies were carried out by photoluminescence spectroscopy and optical transmission spectroscopy. Analysis of the photoluminescence and transmission spectra showed that by changing the concentration of the ligands oleylamine and octylamine, it is possible to control the size of nanocrystals and the photoluminescence wavelength due to the quantum confinement effect. It was shown that the increase in ligands concentration in MAPBr perovskite nanocrystals (NCs) solutions decreases the width of the peak which indicates a better quality of the obtained nanocrystals. An increase in the band gap indicates a decrease in the size of the nanocrystals. Replacing the ligands in the colloidal perovskite NCs solutions leads to shift of the photoluminescence peak from 456 to 535 nm.