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Usevičius G, Turčak J, Zhang Y, Eggeling A, Einorytė Ž, Hope MA, Svirskas Š, Klose D, Kalendra V, Aidas K, Jeschke G, Banys J, Šimėnas M. Probing structural and dynamic properties of MAPbCl 3 hybrid perovskite using Mn 2+ EPR. Dalton Trans 2024; 53:7292-7302. [PMID: 38587489 PMCID: PMC11059044 DOI: 10.1039/d4dt00116h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 04/02/2024] [Indexed: 04/09/2024]
Abstract
Hybrid methylammonium (MA) lead halide perovskites have emerged as materials exhibiting excellent photovoltaic performance related to their rich structural and dynamic properties. Here, we use multifrequency (X-, Q-, and W-band) electron paramagnetic resonance (EPR) spectroscopy of Mn2+ impurities in MAPbCl3 to probe the structural and dynamic properties of both the organic and inorganic sublattices of this compound. The temperature dependent continuous-wave (CW) EPR experiments reveal a sudden change of the Mn2+ spin Hamiltonian parameters at the phase transition to the ordered orthorhombic phase indicating its first-order character and significant slowing down of the MA cation reorientation. Pulsed EPR experiments are employed to measure the temperature dependences of the spin-lattice relaxation T1 and decoherence T2 times of the Mn2+ ions in the orthorhombic phase of MAPbCl3 revealing a coupling between the spin center and vibrations of the inorganic framework. Low-temperature electron spin echo envelope modulation (ESEEM) experiments of the protonated and deuterated MAPbCl3 analogues show the presence of quantum rotational tunneling of the ammonium groups, allowing to accurately probe their rotational energy landscape.
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Affiliation(s)
- Gediminas Usevičius
- Faculty of Physics, Vilnius University, Sauletekio 3, 10257 Vilnius, Lithuania.
| | - Justinas Turčak
- Faculty of Physics, Vilnius University, Sauletekio 3, 10257 Vilnius, Lithuania.
| | - Yuxuan Zhang
- Laboratory of Magnetic Resonance, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Andrea Eggeling
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zurich, Switzerland
| | - Žyginta Einorytė
- Faculty of Physics, Vilnius University, Sauletekio 3, 10257 Vilnius, Lithuania.
| | - Michael Allan Hope
- Laboratory of Magnetic Resonance, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Šarūnas Svirskas
- Faculty of Physics, Vilnius University, Sauletekio 3, 10257 Vilnius, Lithuania.
| | - Daniel Klose
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zurich, Switzerland
| | - Vidmantas Kalendra
- Faculty of Physics, Vilnius University, Sauletekio 3, 10257 Vilnius, Lithuania.
| | - Kestutis Aidas
- Faculty of Physics, Vilnius University, Sauletekio 3, 10257 Vilnius, Lithuania.
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zurich, Switzerland
| | - Jūras Banys
- Faculty of Physics, Vilnius University, Sauletekio 3, 10257 Vilnius, Lithuania.
| | - Mantas Šimėnas
- Faculty of Physics, Vilnius University, Sauletekio 3, 10257 Vilnius, Lithuania.
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Kalendra V, Turčak J, Usevičius G, Karas H, Hülsmann M, Godt A, Jeschke G, Banys J, Morton JJL, Šimėnas M. Q-band EPR cryoprobe. J Magn Reson 2023; 356:107573. [PMID: 37856964 DOI: 10.1016/j.jmr.2023.107573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 10/09/2023] [Accepted: 10/11/2023] [Indexed: 10/21/2023]
Abstract
Following the success of cryogenic EPR signal preamplification at X-band, we present a Q-band EPR cryoprobe compatible with a standard EPR resonator. The probehead is equipped with a cryogenic ultra low-noise microwave amplifier and its protection circuit that are placed close to the sample in the same cryostat. Our cryoprobe maintains the same sample access and tuning which is typical in Q-band EPR, as well as supports high-power pulsed experiments on typical samples. The performance of our setup is benchmarked against that of existing commercial and home-built Q-band spectrometers, using CW EPR and pulsed EPR/ENDOR experiments to reveal a significant sensitivity improvement which reduces the measurement time by a factor of about 40× at 6 K temperature at reduced power levels.
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Affiliation(s)
- Vidmantas Kalendra
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania; Amplify My Probe Ltd., London NW1 1NJ, UK
| | - Justinas Turčak
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - Gediminas Usevičius
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - Hugo Karas
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zurich, Switzerland
| | - Miriam Hülsmann
- Faculty of Chemistry and Center for Molecular Materials (CM(2)), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM(2)), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zurich, Switzerland
| | - Jūras Banys
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - John J L Morton
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Electronic & Electrical Engineering, University College London, London WC1E 7JE, UK
| | - Mantas Šimėnas
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania.
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Kalendra V, Turčak J, Banys J, Morton JJL, Šimėnas M. X- and Q-band EPR with cryogenic amplifiers independent of sample temperature. J Magn Reson 2023; 346:107356. [PMID: 36516664 DOI: 10.1016/j.jmr.2022.107356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/03/2022] [Accepted: 12/04/2022] [Indexed: 06/17/2023]
Abstract
Inspired by the success of NMR cryoprobes, we recently reported a leap in X-band EPR sensitivity by equipping an ordinary EPR probehead with a cryogenic low-noise microwave amplifier placed closed to the sample in the same cryostat [Šimėnas et al. J. Magn. Reson.322, 106876 (2021)]. Here, we explore, theoretically and experimentally, a more general approach, where the amplifier temperature is independent of the sample temperature. This approach brings a number of important advantages, enabling sensitivity improvement irrespective of sample temperature, as well as making it more practical to combine with ENDOR and Q-band resonators, where space in the sample cryostat is often limited. Our experimental realisation places the cryogenic preamplifier within an external closed-cycle cryostat, and we show CW and pulsed EPR and ENDOR sensitivity improvements at both X- and Q-bands with negligible dependence on sample temperature. The cryoprobe delivers signal-to-noise ratio enhancements that reduce the equivalent pulsed EPR measurement time by 16× at X-band and close to 5× at Q-band. Using the theoretical framework we discuss further improvements of this approach which could be used to achieve even greater sensitivity.
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Affiliation(s)
- Vidmantas Kalendra
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania; Amplify My Probe Ltd., London NW1 1NJ, UK
| | - Justinas Turčak
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - Jūras Banys
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - John J L Morton
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Dept. of Electronic & Electrical Engineering, University College London, London WC1E 7JE, UK
| | - Mantas Šimėnas
- Faculty of Physics, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania.
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