Regensburg 2025 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 32: Poster Session II
CPP 32.40: Poster
Donnerstag, 20. März 2025, 09:30–12:00, P3
Morphology Control and Optical Modelling of CsPbBr3 Nanocrystal Films for Emission Orientation Studies — •Lea Kolb, Roshini Jayabalan, and Wolfgang Brütting — Universität Augsburg, 86135 Augsburg, Germany
The remarkable properties of CsPbBr3 perovskite nanocrystals, exhibiting a high photoluminescence quantum yield (PLQY) and a narrow emission linewidth with size- and composition-tunable bandgap, render them promising for the application as emitters in light-emitting diodes (LEDs). While PLQY and charge carrier transport for perovskite LEDs have been in the focus of extensive studies, the orientation of the emissive transition dipole moment (TDM) has not been investigated thoroughly yet. However, for TDM analysis, determining the complex refractive index of the nanocrystal films is crucial. In this work, variable angle spectroscopic ellipsometry (VASE) was used to obtain the optical constants of various samples containing CsPbBr3 nanocrystals. To avoid scattering effects, VASE measurements require homogeneous films with minimal roughness. For this reason, the substrates on which the nanocrystal films were spin-coated had to be modified and the sample fabrication process was optimized. In order to describe the measured data accurately with optical fit models, the morphology and thickness of the films were studied comprehensively by atomic force microscopy (AFM). Finally, angular dependent photoluminescence (ADPL) measurements have been performed and modelled in order to obtain information about the TDM-orientation.
Keywords: Perovskite Nanocrystals; Perovskite LEDs; Variable Angle Spectroscopic Ellipsometry (VASE); Optical constants; Emitter orientation