1
|
Ahmad M, Cruguel H, Ahmadpour M, Vannucchi N, Samie NM, Leuillet C, Generalov A, Li Z, Madsen M, Witkowski N. Uncovering the Electronic State Interplay at Metal Oxide Electron Transport Layer/Nonfullerene Acceptor Interfaces in Stable Organic Photovoltaic Devices. ACS Appl Mater Interfaces 2023; 15:55065-55072. [PMID: 37972316 DOI: 10.1021/acsami.3c11103] [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] [Indexed: 11/19/2023]
Abstract
The implementation of sputter-deposited TiOx as an electron transport layer in nonfullerene acceptor-based organic photovoltaics has been shown to significantly increase the long-term stability of devices compared to conventional solution-processed ZnO due to a decreased photocatalytic activity of the sputtered TiOx. In this work, we utilize synchrotron-based photoemission and absorption spectroscopies to investigate the interface between the electron transport layer, TiOx prepared by magnetron sputtering, and the nonfullerene acceptor, ITIC, prepared in situ by spray deposition to study the electronic state interplay and defect states at this interface. This is used to unveil the mechanisms behind the decreased photocatalytic activity of the sputter-deposited TiOx and thus also the increased stability of the organic solar cell devices. The results have been compared to similar measurements on anatase TiOx since anatase TiOx is known to have a strong photocatalytic activity. We show that the deposition of ITIC on top of the sputter-deposited TiOx results in an oxidation of Ti3+ species in the TiOx and leads to the emergence of a new O 1s peak that can be attributed to the oxygen in ITIC. In addition, increasing the thickness of ITIC on TiOx leads to a shift in the O 1s and C 1s core levels toward higher binding energies, which is consistent with electron transfer at the interface. Resonant photoemission at the Ti L-edge shows that oxygen vacancies in sputtered TiOx lie mostly in the surface region, which contrasts the anatase TiOx where an equal distribution between surface and subsurface oxygen vacancies is observed. Furthermore, it is shown that the subsurface oxygen vacancies in sputtered TiOx are strongly reduced after ITIC deposition, which can reduce the photocatalytic activity of the oxide, while the oxygen vacancies in model anatase TiOx are not affected upon ITIC deposition. This difference can explain the inferior photocatalytic activity of the sputter-deposited TiOx and thus also the increased stability of devices with sputter-deposited TiOx used as an electron transport layer.
Collapse
Affiliation(s)
- Mariam Ahmad
- SDU Centre for Advanced Photovoltaics and Thin-Film Energy Devices (SDU CAPE), Mads Clausen Institute, University of Southern Denmark, Alsion 2, So̷nderborg DK-6400, Denmark
- SDU Climate Cluster, University of Southern Denmark, Odense 5230, Denmark
| | - Hervé Cruguel
- UMR CNRS 7588, Institut des Nanosciences de Paris, Sorbonne Université, Paris F-75005, France
| | - Mehrad Ahmadpour
- SDU Centre for Advanced Photovoltaics and Thin-Film Energy Devices (SDU CAPE), Mads Clausen Institute, University of Southern Denmark, Alsion 2, So̷nderborg DK-6400, Denmark
| | - Noemi Vannucchi
- UMR CNRS 7588, Institut des Nanosciences de Paris, Sorbonne Université, Paris F-75005, France
- Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala 752 36,Sweden
| | - Nahed Mohammad Samie
- UMR CNRS 7588, Institut des Nanosciences de Paris, Sorbonne Université, Paris F-75005, France
| | - Céline Leuillet
- UMR CNRS 7588, Institut des Nanosciences de Paris, Sorbonne Université, Paris F-75005, France
| | | | - Zheshen Li
- ISA, Centre for Storage Ring Facilities, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Bldg. 1520, Aarhus C DK-8000, Denmark
| | - Morten Madsen
- SDU Centre for Advanced Photovoltaics and Thin-Film Energy Devices (SDU CAPE), Mads Clausen Institute, University of Southern Denmark, Alsion 2, So̷nderborg DK-6400, Denmark
- SDU Climate Cluster, University of Southern Denmark, Odense 5230, Denmark
| | - Nadine Witkowski
- UMR CNRS 7588, Institut des Nanosciences de Paris, Sorbonne Université, Paris F-75005, France
| |
Collapse
|
2
|
Preobrajenski A, Generalov A, Öhrwall G, Tchaplyguine M, Tarawneh H, Appelfeller S, Frampton E, Walsh N. FlexPES: a versatile soft X-ray beamline at MAX IV Laboratory. J Synchrotron Radiat 2023:S1600577523003429. [PMID: 37159290 DOI: 10.1107/s1600577523003429] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
FlexPES is a soft X-ray beamline on the 1.5 GeV storage ring at MAX IV Laboratory, Sweden, providing horizontally polarized radiation in the 40-1500 eV photon energy range and specializing in high-resolution photoelectron spectroscopy, fast X-ray absorption spectroscopy and electron-ion/ion-ion coincidence techniques. The beamline is split into two branches currently serving three endstations, with a possibility of adding a fourth station at a free port. The refocusing optics provides two focal points on each branch, and enables either focused or defocused beam on the sample. The endstation EA01 at branch A (Surface and Materials Science) is dedicated to surface- and materials-science experiments on solid samples at ultra-high vacuum. It is well suited not only to all flavours of photoelectron spectroscopy but also to fast (down to sub-minute) high-resolution X-ray absorption measurements with various detectors. Branch B (Low-Density Matter Science) has the possibility to study gas-phase/liquid samples at elevated pressures. The first endstation of this branch, EB01, is a mobile setup for various ion-ion and electron-ion coincidence techniques. It houses a versatile reaction microscope, which can be used for experiments during single-bunch or multi-bunch delivery. The second endstation, EB02, is based on a rotatable chamber with an electron spectrometer for photoelectron spectroscopy studies on primarily volatile targets, and a number of peripheral setups for sample delivery, such as molecular/cluster beams, metal/semiconductor nanoparticle beams and liquid jets. This station can also be used for non-UHV photoemission studies on solid samples. In this paper, the optical layout and the present performance of the beamline and all its endstations are reported.
Collapse
Affiliation(s)
| | | | - Gunnar Öhrwall
- MAX IV Laboratory, Lund University, Box 118, Lund 221 00, Sweden
| | | | - Hamed Tarawneh
- MAX IV Laboratory, Lund University, Box 118, Lund 221 00, Sweden
| | | | - Eleanor Frampton
- MAX IV Laboratory, Lund University, Box 118, Lund 221 00, Sweden
| | - Noelle Walsh
- MAX IV Laboratory, Lund University, Box 118, Lund 221 00, Sweden
| |
Collapse
|
3
|
Poelchen G, Rusinov IP, Schulz S, Güttler M, Mende M, Generalov A, Usachov DY, Danzenbächer S, Hellwig J, Peters M, Kliemt K, Kucherenko Y, Antonov VN, Laubschat C, Chulkov EV, Ernst A, Kummer K, Krellner C, Vyalikh DV. Interlayer Coupling of a Two-Dimensional Kondo Lattice with a Ferromagnetic Surface in the Antiferromagnet CeCo 2P 2. ACS Nano 2022; 16:3573-3581. [PMID: 35156797 DOI: 10.1021/acsnano.1c10705] [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] [Indexed: 06/14/2023]
Abstract
The f-driven temperature scales at the surfaces of strongly correlated materials have increasingly come into the focus of research efforts. Here, we unveil the emergence of a two-dimensional Ce Kondo lattice, which couples ferromagnetically to the ordered Co lattice below the P-terminated surface of the antiferromagnet CeCo2P2. In its bulk, Ce is passive and behaves tetravalently. However, because of symmetry breaking and an effective magnetic field caused by an uncompensated ferromagnetic Co layer, the Ce 4f states become partially occupied and spin-polarized near the surface. The momentum-resolved photoemission measurements indicate a strong admixture of the Ce 4f states to the itinerant bands near the Fermi level including surface states that are split by exchange interaction with Co. The temperature-dependent measurements reveal strong changes of the 4f intensity at the Fermi level in accordance with the Kondo scenario. Our findings show how rich and diverse the f-driven properties can be at the surface of materials without f-physics in the bulk.
Collapse
Affiliation(s)
- Georg Poelchen
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043 Grenoble, France
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany
| | - Igor P Rusinov
- Tomsk State University, 634050 Tomsk, Russia
- St. Petersburg State University, 7/9 Universitetskaya nab., 199034 St. Petersburg, Russia
| | - Susanne Schulz
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany
| | - Monika Güttler
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany
| | - Max Mende
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany
| | | | - Dmitry Yu Usachov
- St. Petersburg State University, 7/9 Universitetskaya nab., 199034 St. Petersburg, Russia
| | - Steffen Danzenbächer
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany
| | - Johannes Hellwig
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438 Frankfurt am Main, Germany
| | - Marius Peters
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438 Frankfurt am Main, Germany
| | - Kristin Kliemt
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438 Frankfurt am Main, Germany
| | - Yuri Kucherenko
- G. V. Kurdyumov Institute for Metal Physics, National Academy of Science of Ukraine, 03142 Kiev, Ukraine
| | - Victor N Antonov
- G. V. Kurdyumov Institute for Metal Physics, National Academy of Science of Ukraine, 03142 Kiev, Ukraine
| | - Clemens Laubschat
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, 01062 Dresden, Germany
| | - Evgueni V Chulkov
- St. Petersburg State University, 7/9 Universitetskaya nab., 199034 St. Petersburg, Russia
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, 20018 Donostia-San Sebastián, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, 20080 Donostia-San Sebastián, Spain
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
| | - Arthur Ernst
- Institut für Theoretische Physik, Johannes Kepler Universität, 4040 Linz, Austria
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany
| | - Kurt Kummer
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Cornelius Krellner
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438 Frankfurt am Main, Germany
| | - Denis V Vyalikh
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
| |
Collapse
|
4
|
Fedorov AV, Poelchen G, Eremeev SV, Schulz S, Generalov A, Polley C, Laubschat C, Kliemt K, Kaya N, Krellner C, Chulkov EV, Kummer K, Usachov DY, Ernst A, Vyalikh DV. Insight into the Temperature Evolution of Electronic Structure and Mechanism of Exchange Interaction in EuS. J Phys Chem Lett 2021; 12:8328-8334. [PMID: 34428055 DOI: 10.1021/acs.jpclett.1c02274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Discovered in 1962, the divalent ferromagnetic semiconductor EuS (TC = 16.5 K, Eg = 1.65 eV) has remained constantly relevant to the engineering of novel magnetically active interfaces, heterostructures, and multilayer sequences and to combination with topological materials. Because detailed information on the electronic structure of EuS and, in particular, its evolution across TC is not well-represented in the literature but is essential for the development of new functional systems, the present work aims at filling this gap. Our angle-resolved photoemission measurements complemented with first-principles calculations demonstrate how the electronic structure of EuS evolves across a paramagnetic-ferromagnetic transition. Our results emphasize the importance of the strong Eu 4f-S 3p mixing for exchange-magnetic splittings of the sulfur-derived bands as well as coupling between f and d orbitals of neighboring Eu atoms to derive the value of TC accurately. The 4f-3p mixing facilitates the coupling between 4f and 5d orbitals of neighboring Eu atoms, which mainly governs the exchange interaction in EuS.
Collapse
Affiliation(s)
- A V Fedorov
- Leibniz Institute for Solid State and Materials Research, 01069 Dresden, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - G Poelchen
- Institut für Festkörper- und Materialphysik, TU Dresden, 01069 Dresden, Germany
- European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - S V Eremeev
- Institute of Strength Physics and Materials Science, 634055 Tomsk, Russia
| | - S Schulz
- Institut für Festkörper- und Materialphysik, TU Dresden, 01069 Dresden, Germany
| | - A Generalov
- Max IV Laboratory, Lund University, Box 118, 22100 Lund, Sweden
| | - C Polley
- Max IV Laboratory, Lund University, Box 118, 22100 Lund, Sweden
| | - C Laubschat
- Institut für Festkörper- und Materialphysik, TU Dresden, 01069 Dresden, Germany
| | - K Kliemt
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, 60438 Frankfurt am Main, Germany
| | - N Kaya
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, 60438 Frankfurt am Main, Germany
| | - C Krellner
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, 60438 Frankfurt am Main, Germany
| | - E V Chulkov
- Tomsk State University, 634050 Tomsk, Russia
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, 20080 San Sebastián/Donostia, Spain
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, 20018 San Sebastián/Donostia, Spain
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- St. Petersburg State University, St. Petersburg, 199034, Russia
| | - K Kummer
- European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - D Yu Usachov
- St. Petersburg State University, St. Petersburg, 199034, Russia
| | - A Ernst
- Institut für Theoretische Physik, Johannes Kepler Universität, A 4040 Linz, Austria
- Max-Planck-Institut für Mikrostrukturphysik, D-06120 Halle, Germany
| | - D V Vyalikh
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
| |
Collapse
|
5
|
Usachov DY, Nechaev IA, Poelchen G, Güttler M, Krasovskii EE, Schulz S, Generalov A, Kliemt K, Kraiker A, Krellner C, Kummer K, Danzenbächer S, Laubschat C, Weber AP, Sánchez-Barriga J, Chulkov EV, Santander-Syro AF, Imai T, Miyamoto K, Okuda T, Vyalikh DV. Cubic Rashba Effect in the Surface Spin Structure of Rare-Earth Ternary Materials. Phys Rev Lett 2020; 124:237202. [PMID: 32603174 DOI: 10.1103/physrevlett.124.237202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/13/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
Spin-orbit interaction and structure inversion asymmetry in combination with magnetic ordering is a promising route to novel materials with highly mobile spin-polarized carriers at the surface. Spin-resolved measurements of the photoemission current from the Si-terminated surface of the antiferromagnet TbRh_{2}Si_{2} and their analysis within an ab initio one-step theory unveil an unusual triple winding of the electron spin along the fourfold-symmetric constant energy contours of the surface states. A two-band k·p model is presented that yields the triple winding as a cubic Rashba effect. The curious in-plane spin-momentum locking is remarkably robust and remains intact across a paramagnetic-antiferromagnetic transition in spite of spin-orbit interaction on Rh atoms being considerably weaker than the out-of-plane exchange field due to the Tb 4f moments.
Collapse
Affiliation(s)
- D Yu Usachov
- St. Petersburg State University, 7/9 Universitetskaya Naberezhnaya, St. Petersburg, 199034, Russia
| | - I A Nechaev
- Department of Electricity and Electronics, FCT-ZTF, UPV-EHU, 48080 Bilbao, Spain
| | - G Poelchen
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - M Güttler
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - E E Krasovskii
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Basque Country, Spain
- Departamento de Física de Materiales UPV/EHU, 20080 Donostia/San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain
| | - S Schulz
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - A Generalov
- Max IV Laboratory, Lund University, Box 118, 22100 Lund, Sweden
| | - K Kliemt
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, D-60438 Frankfurt am Main, Germany
| | - A Kraiker
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, D-60438 Frankfurt am Main, Germany
| | - C Krellner
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, D-60438 Frankfurt am Main, Germany
| | - K Kummer
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble, France
| | - S Danzenbächer
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - C Laubschat
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - A P Weber
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Basque Country, Spain
| | - J Sánchez-Barriga
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - E V Chulkov
- St. Petersburg State University, 7/9 Universitetskaya Naberezhnaya, St. Petersburg, 199034, Russia
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Basque Country, Spain
- Departamento de Física de Materiales UPV/EHU, 20080 Donostia/San Sebastián, Basque Country, Spain
- Centro de Física de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, 20018 Donostia/San Sebastián, Basque Country, Spain
- Tomsk State University, Lenina Avenue 36, 634050, Tomsk, Russia
| | - A F Santander-Syro
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405, Orsay, France
| | - T Imai
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - K Miyamoto
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - T Okuda
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - D V Vyalikh
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain
| |
Collapse
|
6
|
Güttler M, Generalov A, Fujimori SI, Kummer K, Chikina A, Seiro S, Danzenbächer S, Koroteev YM, Chulkov EV, Radovic M, Shi M, Plumb NC, Laubschat C, Allen JW, Krellner C, Geibel C, Vyalikh DV. Divalent EuRh 2Si 2 as a reference for the Luttinger theorem and antiferromagnetism in trivalent heavy-fermion YbRh 2Si 2. Nat Commun 2019; 10:796. [PMID: 30770811 PMCID: PMC6377675 DOI: 10.1038/s41467-019-08688-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 01/25/2019] [Indexed: 11/08/2022] Open
Abstract
Application of the Luttinger theorem to the Kondo lattice YbRh2Si2 suggests that its large 4f-derived Fermi surface (FS) in the paramagnetic (PM) regime should be similar in shape and volume to that of the divalent local-moment antiferromagnet (AFM) EuRh2Si2 in its PM regime. Here we show by angle-resolved photoemission spectroscopy that paramagnetic EuRh2Si2 has a large FS essentially similar to the one seen in YbRh2Si2 down to 1 K. In EuRh2Si2 the onset of AFM order below 24.5 K induces an extensive fragmentation of the FS due to Brillouin zone folding, intersection and resulting hybridization of the Fermi-surface sheets. Our results on EuRh2Si2 indicate that the formation of the AFM state in YbRh2Si2 is very likely also connected with similar changes in the FS, which have to be taken into account in the controversial analysis and discussion of anomalies observed at the quantum critical point in this system.
Collapse
Affiliation(s)
- M Güttler
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, D-01062, Dresden, Germany
| | - A Generalov
- MAX IV Laboratory, Lund University, Box 118, 22100, Lund, Sweden
| | - S I Fujimori
- Materials Sciences Research Center, Japan Atomic Energy Agency, Sayo, Hyogo, 679-5148, Japan
| | - K Kummer
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - A Chikina
- Swiss Light Source and Swiss FEL, Paul Scherrer Institute, CH-5232, Villigen-PSI, Switzerland
| | - S Seiro
- IFW Dresden, Helmholtzstr. 20, 01069, Dresden, Germany
- Max-Planck-Institut für Chemische Physik fester Stoffe, 01187, Dresden, Germany
| | - S Danzenbächer
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, D-01062, Dresden, Germany
| | - Yu M Koroteev
- Tomsk State University, Lenina Av., 36, Tomsk, Russia, 634050
- Institute of Strength Physics and Materials Science, RAS, Tomsk, Russia, 634055
| | - E V Chulkov
- Tomsk State University, Lenina Av., 36, Tomsk, Russia, 634050
- Centro de Física de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, 20018, San Sebastián/Donostia, Spain
- Donostia International Physics Center (DIPC), 20080, San Sebastian, Spain
- Saint Petersburg State University, Saint Petersburg, Russia, 198504
| | - M Radovic
- Swiss Light Source and Swiss FEL, Paul Scherrer Institute, CH-5232, Villigen-PSI, Switzerland
| | - M Shi
- Swiss Light Source and Swiss FEL, Paul Scherrer Institute, CH-5232, Villigen-PSI, Switzerland
| | - N C Plumb
- Swiss Light Source and Swiss FEL, Paul Scherrer Institute, CH-5232, Villigen-PSI, Switzerland
| | - C Laubschat
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, D-01062, Dresden, Germany
| | - J W Allen
- Randall Laboratory, University of Michigan, 450 Church St, Ann Arbor, MI, 48109-1040, USA
| | - C Krellner
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, 60438, Frankfurt am Main, Germany
| | - C Geibel
- Max-Planck-Institut für Chemische Physik fester Stoffe, 01187, Dresden, Germany
| | - D V Vyalikh
- Donostia International Physics Center (DIPC), 20080, San Sebastian, Spain.
- IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| |
Collapse
|
7
|
Konovalova M, Shagdarova B, Zubareva A, Generalov A, Grechikhina M, Svirshchevskaya E. DEVELOPMENT OF MUCOADHESIVE CHITOSAN-BASED DRUG DELIVERY SYSTEM. PCACD 2018. [DOI: 10.15259/pcacd.23.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Chitosan is a highly versatile biopolymer characterised by low toxicity, biocompatibility, and slow but complete biodegradation in the human body, possessing multiple reactive groups. One of the most well-known properties of positively charged chitosan derivatives is their ability to bind mucous membranes. The aim of this work was the analysis of mucoadhesion of unmodified 20 kDa chitosan and its hydrophobic (HC) and hydrophobic quaternised (QHC) derivatives in vitro and ex vivo. Unmodified chitosan formed large aggregates in vitro in keratinocyte and colon cell cultures and ex vivo in murine small intestine and muscle explants. At the same time, HC and especially QHC bound cells in vitro and ex vivo in a fine dotted manner, as evidenced by confocal microscopy. Such a pattern of hydrophobic derivatives distribution provides the possibility to develop mucoadhesive drug delivery systems with increased local drug release and improved chitosan biodegradation.
Collapse
Affiliation(s)
- Mariya Konovalova
- Shemyakin&Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences
| | - Balzhima Shagdarova
- Institute of Bioengineering, Research Centre of Biotechnology of the Russian Academy of Sciences
| | - Anastasia Zubareva
- Institute of Bioengineering, Research Centre of Biotechnology of the Russian Academy of Sciences
| | - Alexander Generalov
- Shemyakin&Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences
| | - Maria Grechikhina
- Shemyakin&Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences
| | - Elena Svirshchevskaya
- Shemyakin&Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences
| |
Collapse
|
8
|
Zhu Q, Zheng K, Abdellah M, Generalov A, Haase D, Carlson S, Niu Y, Heimdal J, Engdahl A, Messing ME, Pullerits T, Canton SE. Correlating structure and electronic band-edge properties in organolead halide perovskites nanoparticles. Phys Chem Chem Phys 2017; 18:14933-40. [PMID: 27189431 DOI: 10.1039/c6cp01843b] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
After having emerged as primary contenders in the race for highly efficient optoelectronics materials, organolead halide perovskites (OHLP) are now being investigated in the nanoscale regime as promising building blocks with unique properties. For example, unlike their bulk counterpart, quantum dots of OHLP are brightly luminescent, owing to large exciton binding energies that cannot be rationalized solely on the basis of quantum confinement. Here, we establish the direct correlation between the structure and the electronic band-edge properties of CH3NH3PbBr3 nanoparticles. Complementary structural and spectroscopic measurements probing long-range and local order reveal that lattice strain influences the nature of the valence band and modifies the subtle stereochemical activity of the Pb(2+) lone-pair. More generally, this work demonstrates that the stereochemical activity of the lone-pair at the metal site is a specific physicochemical parameter coupled to composition, size and strain, which can be employed to engineer novel functionalities in OHLP nanomaterials.
Collapse
Affiliation(s)
- Qiushi Zhu
- Department of Synchrotron Radiation Instrumentation, Lund University, Box 118, 22100, Lund, Sweden
| | - Kaibo Zheng
- Department of Chemical Physics, Lund University, Box 124, 22100, Lund, Sweden. and Gas Processing Center, College of Engineering, Qatar University, P.O. Box 2713, Doha, Qatar
| | - Mohamed Abdellah
- Department of Chemical Physics, Lund University, Box 124, 22100, Lund, Sweden. and Department of Chemistry, Qena Faculty of Science, South Valley University, Qena 83523, Egypt
| | | | - Dörthe Haase
- MAX IV Laboratory, Lund University, Box 118, 22100, Lund, Sweden
| | - Stefan Carlson
- MAX IV Laboratory, Lund University, Box 118, 22100, Lund, Sweden
| | - Yuran Niu
- MAX IV Laboratory, Lund University, Box 118, 22100, Lund, Sweden
| | - Jimmy Heimdal
- MAX IV Laboratory, Lund University, Box 118, 22100, Lund, Sweden
| | - Anders Engdahl
- MAX IV Laboratory, Lund University, Box 118, 22100, Lund, Sweden
| | - Maria E Messing
- Department of Solid State Physics, Lund University, Box 118, 22100, Lund, Sweden
| | - Tonu Pullerits
- Department of Chemical Physics, Lund University, Box 124, 22100, Lund, Sweden.
| | - Sophie E Canton
- IFG Structural Dynamics of (Bio)chemical Systems, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Goettingen, Germany. and FS-SCS, Structural Dynamics with Ultra-short Pulsed X-rays, Deutsches Elektronensynchrotron DESY, Notkestrasse 85, D-22607 Hamburg, Germany
| |
Collapse
|
9
|
Generalov A, Otrokov MM, Chikina A, Kliemt K, Kummer K, Höppner M, Güttler M, Seiro S, Fedorov A, Schulz S, Danzenbächer S, Chulkov EV, Geibel C, Laubschat C, Dudin P, Hoesch M, Kim T, Radovic M, Shi M, Plumb NC, Krellner C, Vyalikh DV. Spin Orientation of Two-Dimensional Electrons Driven by Temperature-Tunable Competition of Spin-Orbit and Exchange-Magnetic Interactions. Nano Lett 2017; 17:811-820. [PMID: 28032768 DOI: 10.1021/acs.nanolett.6b04036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Finding ways to create and control the spin-dependent properties of two-dimensional electron states (2DESs) is a major challenge for the elaboration of novel spin-based devices. Spin-orbit and exchange-magnetic interactions (SOI and EMI) are two fundamental mechanisms that enable access to the tunability of spin-dependent properties of carriers. The silicon surface of HoRh2Si2 appears to be a unique model system, where concurrent SOI and EMI can be visualized and controlled by varying the temperature. The beauty and simplicity of this system lie in the 4f moments, which act as a multiple tuning instrument on the 2DESs, as the 4f projections parallel and perpendicular to the surface order at essentially different temperatures. Here we show that the SOI locks the spins of the 2DESs exclusively in the surface plane when the 4f moments are disordered: the Rashba-Bychkov effect. When the temperature is gradually lowered and the system experiences magnetic order, the rising EMI progressively competes with the SOI leading to a fundamental change in the spin-dependent properties of the 2DESs. The spins rotate and reorient toward the out-of-plane Ho 4f moments. Our findings show that the direction of the spins and the spin-splitting of the two-dimensional electrons at the surface can be manipulated in a controlled way by using only one parameter: the temperature.
Collapse
Affiliation(s)
| | - Mikhail M Otrokov
- Departamento de Fisica de Materiales and CFM-MPC UPV/EHU, Donostia International Physics Center (DIPC) , 20080 San Sebastian, Spain
- Tomsk State University, Lenina Av., 36, 634050 Tomsk, Russia
| | - Alla Chikina
- Institute of Solid State Physics, Dresden University of Technology , Zellescher Weg 16, D-01062 Dresden, Germany
| | - Kristin Kliemt
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt , Max-von-Laue Straße 1, D-60438 Frankfurt am Main, Germany
| | - Kurt Kummer
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, CS40220, F-38043 Grenoble Cedex 9, France
| | - Marc Höppner
- Max Planck Institute for Solid State Research, Heisenberg Straße 1, D-70569 Stuttgart, Germany
| | - Monika Güttler
- Institute of Solid State Physics, Dresden University of Technology , Zellescher Weg 16, D-01062 Dresden, Germany
| | - Silvia Seiro
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, D-01187 Dresden, Germany
| | | | - Susanne Schulz
- Institute of Solid State Physics, Dresden University of Technology , Zellescher Weg 16, D-01062 Dresden, Germany
| | - Steffen Danzenbächer
- Institute of Solid State Physics, Dresden University of Technology , Zellescher Weg 16, D-01062 Dresden, Germany
| | - Evgueni V Chulkov
- Departamento de Fisica de Materiales and CFM-MPC UPV/EHU, Donostia International Physics Center (DIPC) , 20080 San Sebastian, Spain
- Tomsk State University, Lenina Av., 36, 634050 Tomsk, Russia
- Saint Petersburg State University , 198504 Saint Petersburg, Russia
| | - Christoph Geibel
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, D-01187 Dresden, Germany
| | - Clemens Laubschat
- Institute of Solid State Physics, Dresden University of Technology , Zellescher Weg 16, D-01062 Dresden, Germany
| | | | | | - Timur Kim
- Diamond Light Source, Didcot OX11 0DE, U.K
| | | | | | | | - Cornelius Krellner
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt , Max-von-Laue Straße 1, D-60438 Frankfurt am Main, Germany
| | - Denis V Vyalikh
- Departamento de Fisica de Materiales and CFM-MPC UPV/EHU, Donostia International Physics Center (DIPC) , 20080 San Sebastian, Spain
- Institute of Solid State Physics, Dresden University of Technology , Zellescher Weg 16, D-01062 Dresden, Germany
- Saint Petersburg State University , 198504 Saint Petersburg, Russia
- IKERBASQUE, Basque Foundation for Science , 48011 Bilbao, Spain
| |
Collapse
|
10
|
Abstract
The interaction of the ionic liquid [C4 C1 Im][BF4 ] with anatase TiO2 , a model photoanode material, has been studied using a combination of synchrotron radiation photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy. The system is of interest as a model for fundamental electrolyte-electrode and dye-sensitized solar cells. The initial interaction involves degradation of the [BF4 ]- anion, resulting in incorporation of F into O vacancies in the anatase surface. At low coverages, [C4 C1 Im][BF4 ] is found to order at the anatase(101) surface via electrostatic attraction, with the imidazolium ring oriented 32±4° from the anatase TiO2 surface. As the coverage of ionic liquid increases, the influence of the oxide surface on the topmost layers is reduced and the ordering is lost.
Collapse
Affiliation(s)
- Michael Wagstaffe
- School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester, M139PL, UK
| | - Mark J Jackman
- School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester, M139PL, UK
| | - Karen L Syres
- Jeremiah Horrocks Institute, The University of Central Lancashire, Fylde Road, Preston, PR1 2HE, UK
| | | | - Andrew G Thomas
- School of Materials and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M139PL, UK
| |
Collapse
|
11
|
Zheng K, Zhu Q, Abdellah M, Messing ME, Zhang W, Generalov A, Niu Y, Ribaud L, Canton SE, Pullerits T. Exciton Binding Energy and the Nature of Emissive States in Organometal Halide Perovskites. J Phys Chem Lett 2015; 6:2969-75. [PMID: 26267190 DOI: 10.1021/acs.jpclett.5b01252] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Characteristics of nanoscale materials are often different from the corresponding bulk properties providing new, sometimes unexpected, opportunities for applications. Here we investigate the properties of 8 nm colloidal nanoparticles of MAPbBr3 perovskites and contrast them to the ones of large microcrystallites representing a bulk. X-ray spectroscopies provide an exciton binding energy of 0.32 ± 0.10 eV in the nanoparticles. This is 5 times higher than the value of bulk crystals (0.084 ± 0.010 eV), and readily explains the high fluorescence quantum yield in nanoparticles. In the bulk, at high excitation concentrations, the fluorescence intensity has quadratic behavior following the Saha-Langmuir model due to the nongeminate recombination of charges forming the emissive exciton states. In the nanoparticles, a linear dependence is observed since the excitation concentration per particle is significantly less than one. Even the bulk shows linear emission intensity dependence at lower excitation concentrations. In this case, the average excitation spacing becomes larger than the carrier diffusion length suppressing the nongeminate recombination. From these considerations we obtain the charge carrier diffusion length in MAPbBr3 of 100 nm.
Collapse
Affiliation(s)
- Kaibo Zheng
- †Department of Chemical Physics, Lund University, Box 124, 22100, Lund, Sweden
| | - Qiushi Zhu
- §Department of Synchrotron Radiation Instrumentation, Lund University, Box 118, 22100, Lund, Sweden
| | - Mohamed Abdellah
- †Department of Chemical Physics, Lund University, Box 124, 22100, Lund, Sweden
- ‡Department of Chemistry, Qena Faculty of Science, South Valley University, Qena 83523, Egypt
| | - Maria E Messing
- ∥Deptartment of Solid State Physics, Lund University, Box 118, 22100, Lund, Sweden
| | - Wei Zhang
- †Department of Chemical Physics, Lund University, Box 124, 22100, Lund, Sweden
| | | | - Yuran Niu
- ⊥MAX IV Laboratory, Lund University, Box 118, 22100, Lund, Sweden
| | - Lynn Ribaud
- #X-ray Science Division, Advanced Photon Source and Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Sophie E Canton
- ∇IFG Structural Dynamics of (Bio)chemical Systems, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Goettingen, Germany
- ○FS-SCS, Structural Dynamics with Ultra-short Pulsed X-rays, Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, D-22607 Hamburg, Germany
| | - Tõnu Pullerits
- †Department of Chemical Physics, Lund University, Box 124, 22100, Lund, Sweden
| |
Collapse
|
12
|
Höppner M, Seiro S, Chikina A, Fedorov A, Güttler M, Danzenbächer S, Generalov A, Kummer K, Patil S, Molodtsov SL, Kucherenko Y, Geibel C, Strocov VN, Shi M, Radovic M, Schmitt T, Laubschat C, Vyalikh DV. Interplay of Dirac fermions and heavy quasiparticles in solids. Nat Commun 2013; 4:1646. [PMID: 23552061 DOI: 10.1038/ncomms2654] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/26/2013] [Indexed: 11/09/2022] Open
Abstract
Many-body interactions in crystalline solids can be conveniently described in terms of quasiparticles with strongly renormalized masses as compared with those of non-interacting particles. Examples of extreme mass renormalization are on the one hand graphene, where the charge carriers obey the linear dispersion relation of massless Dirac fermions, and on the other hand heavy-fermion materials where the effective electron mass approaches the mass of a proton. Here we show that both extremes, Dirac fermions, like they are found in graphene and extremely heavy quasiparticles characteristic for Kondo materials, may not only coexist in a solid but can also undergo strong mutual interactions. Using the example of EuRh₂Si₂, we explicitly demonstrate that these interactions can take place at the surface and in the bulk. The presence of the linear dispersion is imposed solely by the crystal symmetry, whereas the existence of heavy quasiparticles is caused by the localized nature of the 4f states.
Collapse
Affiliation(s)
- M Höppner
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Patil S, Generalov A, Omar A. The unexpected absence of Kondo resonance in the photoemission spectrum of CeAl2. J Phys Condens Matter 2013; 25:382205. [PMID: 23995018 DOI: 10.1088/0953-8984/25/38/382205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We study the temperature dependent Ce 4f spectral evolution of a well known Kondo system, CeAl2, for a range extending beyond 2 eV below the Fermi level, using photoemission spectroscopy. Interestingly, the spectral evolution is inconsistent with the predictions of the many-body spectral function calculations corresponding to the Kondo resonance interpretation of the screened Ce 4f photoemission features. In order to explain our spectral evolution we propose the phenomenon of collapse of the Kondo singlet wavefunction upon photoelectron kinetic energy measurement. Our proposal suggests that the screened final states in photoemission spectroscopy are not quantum states.
Collapse
Affiliation(s)
- S Patil
- Institut für Festkörperphysik, Technische Universität Dresden, D-01062 Dresden, Germany.
| | | | | |
Collapse
|