Synthesis of brightly luminescent colloidal formamidinium lead bromide perovskite FAPbBr₃ nanoplatelets with tunable emission

¹ University Hassan II of Casablanca, Faculty of sciences Ben M’sik, Department of Chemistry, Laboratory of Physical Chemistry of Materials, Casablanca, Morocco
² University of Pisa, Department of Chemistry and Industrial Chemistry, Pisa, Italy
³ Italian National Council for Research - Institute for the Chemistry of OrganoMetallic Compounds, Florence, Italy
⁴ University of Florence, Department of Chemistry“U. Schiff”, Florence, Italy

^* Corresponding author: nabilajarmouni@gmail.com

Abstract

Hybrid halide perovskites are semicondoctor materials with desirable characteristics of color-tunable and narrow-band emissions for lighting and display technology. They have size-tunable emissions due to quantum size effects. In this work, the Formamidinium Lead Bromide perovskite CH(NH₂)₂PbBr₃ nanoplatelets (NPLs) were successfully synthesized by ligand-assisted reprecipitation method under room condition, in which the emission color-tunability was realized via quantum size effect without anion–halide mixing, by varying the oleylamine to oleic acid volume ratio as surfactants, while the total amount of oleic acid remained unchanged. We are able to adjust the optical proprieties of FAPbBr₃ NPLs and, consequently, their structural properties. The obtained colloidal solutions of FAPbBr₃ nanoplatelets with uniform size exhibited different photoluminescence wavelengths covering the spectral region from 440 to 525 nm. The maximum absolute PL quantum yield (PLQY) of the green emission was measured to be as high as 80% at room temperature. The size of FAPbBr3 NPLs could be effectively tuned from 15.5 to 38.1 nm with an increase in the oleylamine and oleic acid ligands ratio.