Berlin 2018 – wissenschaftliches Programm

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SYTH: Symposium Terahertz physics: toward probing and controlling of materials on the nanoscale

SYTH 1: Terahertz Physics: Toward Probing and Controlling of Materials on the Nanoscale

SYTH 1.1: Hauptvortrag

Donnerstag, 15. März 2018, 09:30–10:00, H 0105

Extracting the electrical properties of metal halide perovskite semiconductors using transient terahertz spectroscopy — •Michael B. Johnston — Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, U.K.

Metal halide perovskite semiconductors are currently showing great promise for use in thin-film photovoltaic cells. These semiconductors may be deposited by a variety of methods including vapour deposition and solution processing, and the resulting films possess a high absorption coefficient and relatively benign defect chemistry. The prototypical metal halide perovskite is methyl ammonium lead triiodide with a 1.6eV bandgap at room temperature, however by altering the chemical composition it is possible to produce a large family of metal halide perovskite semiconductors with varying physical properties and bandgaps that span the full visible spectrum [1].

Time-resolved terahertz photoconductivity spectroscopy in an excellent non-contact probe of charge carrier dynamics in semiconductors. Using this technique, the fundamental charge recombination mechanisms in metal halide perovskite materials are revealed, allowing prediction of the electronics and optoelectronic properties of these novel semiconductors [2]. Using appropriate analysis, Shockley-Read-Hall, bimolecular and Auger recombination constants may be extracted [3] and exploited in the design of new solar cells and lasers.

[1] LM Herz, Annu. Rev. Phys. Chem. 67:65, 2016. [2] MB Johnston, LM Herz Accounts Chem. Res., 49:146, 2016. [3] TW Crothers, et al Nano Lett., 17:5782, 2017.