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O: Fachverband Oberflächenphysik

O 108: Electron-Driven Processes at Surfaces and Interfaces

O 108.6: Vortrag

Donnerstag, 19. März 2020, 16:15–16:30, TRE Ma

Photocarrier dynamics in CsPbBr3 perovskite single crystals — •Serhii Polishchuk¹, Michele Puppin¹, Alberto Crepaldi², Dmitry Dirin³, Olga Nazarenko³, Maksym Kovalenko³, Marco Grioni², and Majed Chergui¹ — ¹LSU and LACUS, EPFL, Lausanne, Switzerland — ²IoP and LACUS, EPFL, Lausanne, Switzerland — ³LAC, ETHZ, Zurich, Switzerland

The ability to harvest hot carrier energy can elevate the power conversion efficiency of modern single junction solar cells by up to 25%. In conventional solar materials the photogenerated charge carriers loose the excess electronic energy before the charge collection happens. The understanding of the energy dissipation mechanisms is the fundamental step towards the emergence of hot carrier photovoltaics. The time- and angle-resolved photoelectron spectroscopy (TR-ARPES) is a direct probe of the electronic structure and carrier dynamics of solar materials. The photogenerated electron cooling to the conduction band minimum has been visualized and tracked by TR-ARPES in fully-inorganic CsPbBr3 perovskite single crystals. The results yield the cooling timescale of approximately 250 fs, and the sub-ps population decay. While hot phonon bottleneck and Auger heating are considered to govern electron cooling dynamics, the surface and Auger recombination, and the diffusion into the bulk supposedly define the apparent population decay. These findings showcase the capabilities of this experimental approach and constitute an important milestone in understanding the processes controlling the ultrafast photocarrier dynamics in CsPbBr3 semiconductor.