Photoluminescence and photovoltaic properties of cesium lead bromide nanocrystals with linoleic acid ligand

Abstract

Cesium lead bromide (CsPbBr3) nanocrystals (NCs) were synthesized using the ligand-assisted reprecipitation (LARP) method, with linoleic acid (LA) and oleylamine (OlAm) as ligands. The crystal structures of the samples depend on the ligand used in the synthesis. Sample-1, with LA-OlAm as the ligand, showed an orthorhombic crystal structure, whereas Sample-2, with OlAm only, showed a tetragonal crystal structure. These samples exhibited slightly different photoluminescence (PL) characteristics, where the PL peak of Sample-1 appeared at 521.4 nm, whereas the PL peak of Sample-2 appeared at 524.1 nm. Sample-1 showed brighter PL than that of Sample-2. These differences are strongly related to their crystal structures and degree of crystallization, which is also evident from the differences in the chemical states of the Br and Pb ions on the NCs surface, as depicted by the X-Ray Photoelectron Spectroscopy (XPS) spectra. In addition, despite exhibiting PL characteristics, these CsPbBr3 NCs also exhibit photovoltaic properties.