Regensburg 2019 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 14: PhD-Symposium: Photoluminescence of halide perovskites:
What does it tell us and what not? (joint session DS/HL/AKjDPG)

HL 14.4: Talk

Tuesday, April 2, 2019, 10:45–11:00, H32

The impact of lead iodide on the recombination kinetics in metal halide perovskites — •Aboma Merdasa¹, Alexandros Kiligaridis², Carolin Rehermann¹, Mojtaba Abdi-Jalebi³, Jonas Stöber², Boris Louis², Marina Gerhard², Samuel D. Stranks³, Eva L. Unger^1,2, and Ivan G. Scheblykin² — ¹Young Investigator Group Hybrid Materials Formation and Scaling, Helmholtz-Zentrum Berlin für Materialen und Energie, Berlin, Germany — ²Chemical Physics and NanoLund, Lund University, Lund, Sweden. — ³Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom.

Metal halide perovskites are promising semiconductor materials for photovoltaic devices with solar cell efficiencies soaring over 20%, but understanding the fundamental operational principles are lagging behind. One example is the role and influence of lead iodide (PbI2) reportedly being both beneficial and detrimental for a device. Herein, we present a study on the impact of lead iodide on the charge-carrier recombination kinetics in methylammonium lead triiodide (MAPbI3) thin films. We simultaneously acquire spectrally-resolved photoluminescence quantum yield and time-resolved photoluminescence lifetime at excitation wavelengths ranging from 450 nm to 780 nm during hours of light-soaking, and identify a unique radiative recombination mechanism occurring at the PbI2/MAPbI3 interface when charge carriers are generated in PbI2. We thereby provide important insight into the long-debated question of whether excess PbI2 is beneficial or detrimental for charge carrier dynamics in perovskite solar absorber materials.