Berlin 2024 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 22: Focus Session: Young Semiconductor Forum

HL 22.4: Poster

Dienstag, 19. März 2024, 11:00–15:30, Poster F

Tunable White-Light Emission from Self-Trapped Excitons in Low-Dimensional Hybrid Perovskites — •Philip Klement¹, Lukas Gümbel¹, Johanna Heine², and Sangam Chatterjee¹ — ¹Institute of Experimental Physics I, JLU Gießen, Germany — ²Department of Chemistry, Universität Marburg, Germany

Lead halide perovskites and related main group metal halide materials hold immensie potential for advanced solar cells and LEDs. Efficient light emission in these materials relies on self-trapped excitons, where excitations create temporary defects that trap excitons within the crystal lattice. However, the complex interplay of factors like ground- and excited-state distortions, lattice softness, and electron-phonon coupling hinders designing these materials for specific optical properties. Here, we study various antimony and bismuth halide compounds with systematic variations in composition, anion dimensionality, connectivity, and chiral organic cation. The unique crystal structure of these compounds facilitates the formation of self-trapped excitons, resulting in broad photoluminescence emission with large Stokes shifts, which we correlate with structural parameters. Challenging conventional wisdom, we present single layers of a 1D hybrid perovskite, questioning the belief that atomically thin 2D materials require in-plane covalent bonding. The thickness-dependent exciton self-trapping induces a pronounced shift in emission energy, revealing distinctive exciton physics. Furthermore, we investigate charge carrier diffusion using temporally and spatially resolved photoluminescence spectroscopy. Our findings deepen the comprehension of emission processes in hybrid materials.

Keywords: perovskite; white-light emission; self-trapped exciton; ultrathin; 2D