Study of luminescent and energy properties of CsPbBr3 and CsPbI3 nanoplatelets

Sammanfattning: Halide perovskite semiconductor nanocrystals have been studied a lot recently because they allow a precise control over the entire visible emission spectrum and as a result, the possibility of a variety of light-emitting applications. In this study, cesium lead bromide CsPbBr3 and cesium lead iodide CsPbI3 nanoplatelets of 3, 4 and 5 monolayers (ML) have been synthesized. The absorbance and emission of each solutions and monolayer are measured and analyzed in terms of the change in excitonic nature. The results show that the exciton peak decreases with the number of monolayers with a stronger excitonic behavior in the Bromide system in comparison to the Iodine perovskite with nearly no excitonic feature for the 5 ML system. An analysis of the apparent Stokes-shift show that it increases with the number of monolayer for CsPbBr3 in comparison with the Iodide system where it decreases. The vibrational properties were quantified with Raman spectroscopy and showed that a second signifying peak of the perovskite vibration change upon quantum confinement.