Light Absorption Coefficient of CsPbBr₃ Perovskite Nanocrystals

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Colloidal cesium lead bromide (CsPbBr3) nanocrystals (NCs) are promising optoelectronic materials.
• Accurate characterization of NC size, composition, and optical properties is crucial for their application.
• Understanding NC stoichiometry impacts their performance and stability.

Purpose of the Study:

• To precisely determine the size, composition, and intrinsic absorption coefficient (μi) of CsPbBr3 NCs.
• To investigate the stoichiometric nature of CsPbBr3 NCs using advanced analytical techniques.
• To establish a method for quantifying CsPbBr3 nanocolloid concentration.

Main Methods:

• Inductively coupled plasma mass spectrometry (ICP-MS) for elemental composition analysis.
• UV-vis absorption spectroscopy for optical property determination.
• Transmission electron microscopy (TEM) and Rutherford backscattering (RBS) for size and composition verification.

Main Results:

• ICP-MS analysis revealed a consistent excess of lead in all studied CsPbBr3 NC samples.
• Rutherford backscattering measurements indicated that lead enrichment correlates with increased bromide content.
• The intrinsic absorption coefficient (μi) was found to be size-independent at high photon energies.

Conclusions:

• CsPbBr3 NCs exhibit nonstoichiometric compositions with a lead excess.
• The size-independent nature of μi at high energies enables concentration determination.
• A combined approach of absorption spectroscopy and a CsPbBr3 sizing curve allows for accurate nanocolloid quantification.