Publications by authors named "Andrei Petsiuk"

4 Publications

  • Page 1 of 1

The Role of Bulk and Interface Recombination in High-Efficiency Low-Dimensional Perovskite Solar Cells.

Adv Mater 2019 Jul 5;31(30):e1901090. Epub 2019 Jun 5.

Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476, Potsdam-Golm, Germany.

2D Ruddlesden-Popper perovskite (RPP) solar cells have excellent environmental stability. However, the power conversion efficiency (PCE) of RPP cells remains inferior to 3D perovskite-based cells. Herein, 2D (CH (CH ) NH ) (CH NH ) Pb I perovskite cells with different numbers of [PbI ] sheets (n = 2-4) are analyzed. Photoluminescence quantum yield (PLQY) measurements show that nonradiative open-circuit voltage (V ) losses outweigh radiative losses in materials with n > 2. The n = 3 and n = 4 films exhibit a higher PLQY than the standard 3D methylammonium lead iodide perovskite although this is accompanied by increased interfacial recombination at the top perovskite/C interface. This tradeoff results in a similar PLQY in all devices, including the n = 2 system where the perovskite bulk dominates the recombination properties of the cell. In most cases the quasi-Fermi level splitting matches the device V within 20 meV, which indicates minimal recombination losses at the metal contacts. The results show that poor charge transport rather than exciton dissociation is the primary reason for the reduction in fill factor of the RPP devices. Optimized n = 4 RPP solar cells had PCEs of 13% with significant potential for further improvements.
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http://dx.doi.org/10.1002/adma.201901090DOI Listing
July 2019

Pulse picker for synchrotron radiation driven by a surface acoustic wave: erratum.

Opt Lett 2018 06;43(11):2490

An erratum is presented to correct the typographical errors concerning the composition of the multilayer used in the experiment in Opt. Lett. 42, 1915.
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http://dx.doi.org/10.1364/OL.43.002490DOI Listing
June 2018

Pulse picker for synchrotron radiation driven by a surface acoustic wave.

Opt Lett 2017 May;42(10):1915-1918

A functional test for a pulse picker for synchrotron radiation was performed at Diamond Light Source. The purpose of a pulse picker is to select which pulse from the synchrotron hybrid-mode bunch pattern reaches the experiment. In the present work, the Bragg reflection on a Si/B4C multilayer was modified using surface acoustic wave (SAW) trains. Diffraction on the SAW alters the direction of the x rays and it can be used to modulate the intensity of the x rays that reach the experimental chamber. Using electronic modulation of the SAW amplitude, it is possible to obtain different scattering conditions for different x-ray pulses. To isolate the single bunch, the state of the SAW must be changed in the short time gap between the pulses. To achieve the necessary time resolution, the measurements have been performed in conical diffraction geometry. The achieved time resolution was 120 ns.
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http://dx.doi.org/10.1364/OL.42.001915DOI Listing
May 2017

Observation of sagittal X-ray diffraction by surface acoustic waves in Bragg geometry.

J Appl Crystallogr 2017 Apr 14;50(Pt 2):525-530. Epub 2017 Mar 14.

Helmholtz Zentrum Berlin für Materialien und Energie, Germany; Freie Universität Berlin, Germany.

X-ray Bragg diffraction in sagittal geometry on a Y-cut langasite crystal (LaGaSiO) modulated by Λ = 3 µm Rayleigh surface acoustic waves was studied at the BESSY II synchrotron radiation facility. Owing to the crystal lattice modulation by the surface acoustic wave diffraction, satellites appear. Their intensity and angular separation depend on the amplitude and wavelength of the ultrasonic superlattice. Experimental results are compared with the corresponding theoretical model that exploits the kinematical diffraction theory. This experiment shows that the propagation of the surface acoustic waves creates a dynamical diffraction grating on the crystal surface, and this can be used for space-time modulation of an X-ray beam.
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http://dx.doi.org/10.1107/S1600576717002977DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5377346PMC
April 2017