Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 84: Focus Session (CPP with HL): Hybrid photovoltaics and perovskites II

HL 84.3: Talk

Thursday, March 19, 2015, 16:00–16:15, C 130

Morphology-dependent ultrafast spectroscopy of lead-halide perovskite for electro-optical applications — •Simon Bretschneider, Melike Karakus, Valentin Kamm, Enrique Cánovas, and Frédéric Laquai — Max Planck Institut für Polymerforschung, Mainz

Lead-halide perovskite have emerged as a new class of materials for electro-optical, especially photovoltaic applications with power conversion efficiencies now up to 20% [1]. High-performance electro-optical devices rely on perovskite films without pinholes, flat surface and well-defined thickness. Due to the organic/inorganic nature of the lead-halide perovskite and the criticalness of a pure perovskite phase without impurities of the precursors, utilization of solution-processing is non-trivial.

The combination of time-resolved photoluminescence and transient absorption spectroscopy is a powerful tool, which allows for the investigation of generation and recombination of charge carriers in lead-halide perovskite films on a femto- to microsecond timescale and across a spectral range from Vis to NIR. In this work, we present pump-probe transient absorption measurements of solution-processed lead-halide perovskite films grown in ambient and dry nitrogen atmosphere using different post-processing annealing schemes. The findings of ultrafast spectroscopy suggest that the performance of lead-halide perovskite films for electro-optical applications relies more on homogeneous films than on specific crystal sizes.

[1]NREL Chart of record cell efficiencies (28.11.2014).