Regensburg 2019 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 2: Hybrid and Perovskite Photovoltaics I
CPP 2.9: Vortrag
Montag, 1. April 2019, 12:00–12:15, H18
Origin of Efficient Photoluminescence in Alloyed Perovskites: Photodoping from Localized Charge Accumulation Regions — •Sascha Feldmann1, Stuart Macpherson1, Jasmine Rivett1, Mojtaba Abdi-Jalebi1, Guangjun Nan2, Gregory Tainter1, Richard Friend1, Henning Sirringhaus1, Michael Saliba3, David Beljonne4, Samuel Stranks1, and Felix Deschler1 — 1Cavendish Laboratory, University of Cambridge, Cambridge, UK — 2Department of Physics, Zhejiang Normal University, Jinhua 321004, China — 3Adolphe Merkle Institute, University of Fribourg, CH-1700 Fribourg, Switzerland — 4Chimie des Matériaux Nouveaux, Université de Mons, B-7000 Mons, Belgium
Metal-halide perovskites have emerged as exceptional semiconductors for optoelectronic applications. Here, we reveal the origin of the improved optoelectronic performance arising from compositional engineering by tracking charge carrier dynamics in alloyed perovskites with time-resolved spectroscopy. In contrast to single-halide perovskites, we find that luminescence yields show weak dependence on carrier density and remain high even for photo-excited carrier densities far below solar illumination conditions. We show that the carrier recombination regime changes from second to first order within the first tens of nanoseconds after excitation. Supported by evidence of microscale variations in optical bandgap, electrically-gated transport measurements and first-principles calculations, we propose that spatially-varying energetic disorder in the electronic states leads to local accumulation of one charge carrier type, creating photodoped p- and n-type regions.