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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Poster Session I

CPP 17.33: Poster

Monday, March 27, 2023, 18:00–20:00, P3

Giant Electrostriction in Lead Halide Perovskite MAPbI₃ Films as Measured with Double-Modulated Interferometry — •Philipp Ramming¹, Marvin Malchau², Emma Rauland¹, Anna Köhler¹, and Lothar Kador² — ¹Experimental Physics II, University of Bayreuth, Germany — ²Institute of Physics and BIMF, University of Bayreuth, Germany

Hybrid lead halide perovskite semiconductor MAPbI₃ and similar materials have attracted much recent interest for photovoltaic devices. Upon application of moderate electrical fields, MAPbI₃ exhibits very large electrostriction effects. The thickness variation was measured with high precision using a double-modulation interferometer set-up. Phase modulation of the laser light and mechanical modulation of the interferometric path difference were employed. With field strengths on the order of 100 kV/cm, the relative thickness change of a polycrystalline film of 1 micron thickness can be as large as several per cent. The electrostriction varies with the square of the field strength; it is strongest at very low frequencies below one Hertz and decreases quickly at higher frequencies. The effect is compared to recently published data obtained on perovskite single crystals.