Incorporation of Cesium ions in FAPbBr₃ quantum dots: Spectroscopic characterization for light-emitting application

Background: Hybrid perovskite quantum dots (PQDs) are the good light harvesters due to their outstanding optical and electrical properties, which, aroused great interest of scientists in perovskite materials now a day. But FAPbBr₃ PQDs still suffering due to lower stability, complicated synthesis process and lower color gamut of devices. Methods: FA_1-xCs_xPbBr₃ PQDs were fabricated via the rapid ligand-assisted reprecipitation processes thru the variation in the concentrations of cesium (Cs⁺) ions from 0 to 100 mol%. Significant findings: To overcome the stability issues, Cs⁺ was incorporated into FAPbBr₃ PQDs that demonstrated distinctive PL emission peak shifting towards the blue region. FA_1-xCs_xPbBr₃ PQDs doped with 80 mol% of Cs⁺ ions showed a high color purity of 88% as well as a photoluminescence quantum yield (PLQY) of 85%. Moreover, FA_1-xCs_xPbBr₃ PQDs doped with 80 mol% of Cs⁺ ions exhibited good environmental stability in the ambient conditions. The color gamut of the synthesized white light-emitting devices fabricated with FA_1-xCs_xPbBr₃ PQDs at cesium concentrations of 80 mol% was 118% of the NTSC. The present research indicated that the incorporation of cesium ions in FAPbBr₃ PQDs was an effective method to prepare PQDs with a high PLQY, color gamut, narrow bandwidth emission, good environmental stability.