TY  - JOUR
A1  - Kirchartz, Thomas
A1  - Márquez, José A.
A1  - Stolterfoht, Martin
A1  - Unold, Thomas
T1  - Photoluminescence-based characterization of halide perovskites for photovoltaics
JF  - Advanced Energy Materials
N2  - Photoluminescence spectroscopy is a widely applied characterization technique for semiconductor materials in general and halide perovskite solar cell materials in particular. It can give direct information on the recombination kinetics and processes as well as the internal electrochemical potential of free charge carriers in single semiconductor layers, layer stacks with transport layers, and complete solar cells. The correct evaluation and interpretation of photoluminescence requires the consideration of proper excitation conditions, calibration and application of the appropriate approximations to the rather complex theory, which includes radiative recombination, non-radiative recombination, interface recombination, charge transfer, and photon recycling. In this article, an overview is given of the theory and application to specific halide perovskite compositions, illustrating the variables that should be considered when applying photoluminescence analysis in these materials.
KW  - metal halide perovskites
KW  - numerical simulations
KW  - photoluminescence
KW  - photon recycling
Y1  - 2020
U6  - https://doi.org/10.1002/aenm.201904134
SN  - 1614-6832
SN  - 1614-6840
VL  - 10
IS  - 26
SP  - 1
EP  - 21
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - GEN
A1  - Kirchartz, Thomas
A1  - Márquez, José A.
A1  - Stolterfoht, Martin
A1  - Unold, Thomas
T1  - Photoluminescence-based characterization of halide perovskites for photovoltaics
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Photoluminescence spectroscopy is a widely applied characterization technique for semiconductor materials in general and halide perovskite solar cell materials in particular. It can give direct information on the recombination kinetics and processes as well as the internal electrochemical potential of free charge carriers in single semiconductor layers, layer stacks with transport layers, and complete solar cells. The correct evaluation and interpretation of photoluminescence requires the consideration of proper excitation conditions, calibration and application of the appropriate approximations to the rather complex theory, which includes radiative recombination, non-radiative recombination, interface recombination, charge transfer, and photon recycling. In this article, an overview is given of the theory and application to specific halide perovskite compositions, illustrating the variables that should be considered when applying photoluminescence analysis in these materials.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1419 
KW  - metal halide perovskites
KW  - numerical simulations
KW  - photoluminescence
KW  - photon recycling
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-519702
SN  - 1866-8372
IS  - 26
ER  - 
TY  - JOUR
A1  - Stolterfoht, Martin
A1  - Wolff, Christian Michael
A1  - Marquez, Jose A.
A1  - Zhang, Shanshan
A1  - Hages, Charles J.
A1  - Rothhardt, Daniel
A1  - Albrecht, Steve
A1  - Burn, Paul L.
A1  - Meredith, Paul
A1  - Unold, Thomas
A1  - Neher, Dieter
T1  - Visualization and suppression of interfacial recombination for high-efficiency large-area pin perovskite solar cells
JF  - Nature Energy
N2  - The performance of perovskite solar cells is predominantly limited by non-radiative recombination, either through trap-assisted recombination in the absorber layer or via minority carrier recombination at the perovskite/transport layer interfaces. Here, we use transient and absolute photoluminescence imaging to visualize all non-radiative recombination pathways in planar pintype perovskite solar cells with undoped organic charge transport layers. We find significant quasi-Fermi-level splitting losses (135 meV) in the perovskite bulk, whereas interfacial recombination results in an additional free energy loss of 80 meV at each individual interface, which limits the open-circuit voltage (V-oc) of the complete cell to similar to 1.12 V. Inserting ultrathin interlayers between the perovskite and transport layers leads to a substantial reduction of these interfacial losses at both the p and n contacts. Using this knowledge and approach, we demonstrate reproducible dopant-free 1 cm(2) perovskite solar cells surpassing 20% efficiency (19.83% certified) with stabilized power output, a high V-oc (1.17 V) and record fill factor (>81%).
KW  - Energy science and technology
KW  - Solar cells
Y1  - 2018
U6  - https://doi.org/10.1038/s41560-018-0219-8
SN  - 2058-7546
VL  - 3
IS  - 10
SP  - 847
EP  - 854
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Ramos-Larios, Gerardo
A1  - Toala, Jesús Alberto
A1  - Rodriguez-Gonzalez, Janis B.
A1  - Guerrero, Martin A.
A1  - Gomez-Gonzalez, Víctor Mauricio Alfonso
T1  - Rings and arcs around evolved stars - III. Physical conditions of the ring-like structures in the planetary nebula IC 4406 revealed by MUSE
JF  - Monthly notices of the Royal Astronomical Society
N2  - We present the analysis of Very Large Telescope Multi Unit Spectroscopic Explorer (MUSE) observations of the planetary nebula (PN) IC 4406. MUSE images in key emission lines are used to unveil the presence of at least five ring-like structures north and south of the main nebula of IC4406. MUSE spectra are extracted from the rings to unambiguously assess for the first time in a PN their physical conditions, electron density (n(e)), and temperature (T-e). The rings are found to have similar T-e as the rim of the main nebula, but smaller n(e). Ratios between different ionic species suggest that the rings of IC4406 have a lower ionization state than the main cavity, in contrast to what was suggested for the rings in NGC 6543, the Cat's Eye Nebula.
KW  - stars: evolution
KW  - stars: winds, outflows
KW  - planetary nebulae: general;
KW  - planetary nebulae: individual: IC4406
Y1  - 2022
U6  - https://doi.org/10.1093/mnras/stac605
SN  - 0035-8711
SN  - 1365-2966
VL  - 513
IS  - 2
SP  - 2862
EP  - 2868
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - CHAP
A1  - Dahling, Volker
A1  - May, Susann
A1  - Greiner, Timo
A1  - Thoma, Samuel
A1  - Peter, Sebastian von
A1  - Schwantes, Ulrich
A1  - Rapp, Michael A.
A1  - Heinze, Martin
T1  - Verschreibungspraxis von Psychopharmaka in brandenburgischen Pflegeheimen
T2  - Zeitschrift für Gerontologie und Geriatrie : Organ der Deutschen Gesellschaft für Gerontologie und Geriatrie
T2  - Prescribing practice of psychotropic drugs in Brandenburg nursing homes
Y1  - 2021
SN  - 0948-6704
SN  - 1435-1269
VL  - 54
IS  - SUPPL 1
SP  - S26
EP  - S26
PB  - Springer Medizin
CY  - Heidelberg
ER  - 
TY  - JOUR
A1  - Strasser, A
A1  - Ostermeyer, Martin
T1  - Improving the brightness of side pumped power amplifiers by using core doped ceramic rods
N2  - In side pumped laser head geometries good extraction of energy has to be weighted against diffraction effects of the amplified beam. Beam clipping at the aperture of laser rods can be avoided by using an undoped cladding around the doped core. The wings of e. g. Gaussian beams can be accommodated in the cladding. Phase distortion by the refractive index step of the rod can be compensated by a phase conjugating mirror in double pass configuration. In our proof of principle experiment the brightness of the beam from core doped amplifier rods was shown to be doubled compared to a conventional rod of the same outer diameter. (c) 2006 Optical Society of America
Y1  - 2006
ER  - 
TY  - JOUR
A1  - Meyer, Dominique M.-A.
A1  - Velazquez, Pablo F.
A1  - Petruk, Oleh
A1  - Chiotellis, Alexandros
A1  - Pohl, Martin
A1  - Camps-Farina, Artemi
A1  - Petrov, Miroslav
A1  - Reynoso, Estela M.
A1  - Toledo-Roy, Juan C.
A1  - Schneiter, E. Matias
A1  - Castellanos-Ramirez, Antonio
A1  - Esquivel, Alejandro
T1  - Rectangular core-collapse supernova remnants
BT  - application to Puppis A
JF  - Monthly notices of the Royal Astronomical Society
N2  - Core-collapse supernova remnants are the gaseous nebulae of galactic interstellar media (ISM) formed after the explosive death of massive stars. Their morphology and emission properties depend both on the surrounding circumstellar structure shaped by the stellar wind-ISM interaction of the progenitor star and on the local conditions of the ambient medium. In the warm phase of the Galactic plane (n approximate to 1 cm(-3), T approximate to 8000 K), an organized magnetic field of strength 7 mu G has profound consequences on the morphology of the wind bubble of massive stars at rest. In this paper, we show through 2.5D magnetohydrodynamical simulations, in the context of a Wolf-Rayet-evolving 35 M 0 star, that it affects the development of its supernova remnant. When the supernova remnant reaches its middle age (15-20 kyr), it adopts a tubular shape that results from the interaction between the isotropic supernova ejecta and the anisotropic, magnetized, shocked stellar progenitor bubble into which the supernova blast wave expands. Our calculations for non-thermal emission, i.e. radio synchrotron and inverse-Compton radiation, reveal that such supernova remnants can, due to projection effects, appear as rectangular objects in certain cases. This mechanism for shaping a supernova remnant is similar to the bipolar and elliptical planetary nebula production by wind-wind interaction in the low-mass regime of stellar evolution. If such a rectangular core-collapse supernova remnant is created, the progenitor star must not have been a runaway star. We propose that such a mechanism is at work in the shaping of the asymmetric core-collapse supernova remnant Puppis A.
KW  - stars: evolution
KW  - stars: massive
KW  - ISM: supernova remnants
KW  - methods: MHD
Y1  - 2022
U6  - https://doi.org/10.1093/mnras/stac1832
SN  - 0035-8711
SN  - 1365-2966
VL  - 515
IS  - 1
SP  - 594
EP  - 605
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Meyer, Dominique M.-A.
A1  - Petrov, Mykola
A1  - Pohl, Martin
T1  - Wind nebulae and supernova remnants of very massive stars
JF  - Monthly notices of the Royal Astronomical Society
N2  - A very small fraction of (runaway) massive stars have masses exceeding 60-70 M-circle dot and are predicted to evolve as luminous blue variable and Wolf-Rayet stars before ending their lives as core-collapse supernovae. Our 2D axisymmetric hydrodynamical simulations explore how a fast wind (2000 km s(-1)) and high mass-loss rate (10(-5)M(circle dot) yr(-1)) can impact the morphology of the circumstellar medium. It is shaped as 100 pc-scale wind nebula that can be pierced by the driving star when it supersonically moves with velocity 20-40 km s(-1) through the interstellar medium (ISM) in the Galactic plane. The motion of such runaway stars displaces the position of the supernova explosion out of their bow shock nebula, imposing asymmetries to the eventual shock wave expansion and engendering Cygnus-loop-like supernova remnants. We conclude that the size (up to more than 200 pc) of the filamentary wind cavity in which the chemically enriched supernova ejecta expand, mixing efficiently the wind and ISM materials by at least 10 per cent in number density, can be used as a tracer of the runaway nature of the very massive progenitors of such 0.1Myr old remnants. Our results motivate further observational campaigns devoted to the bow shock of the very massive stars BD+43 degrees 3654 and to the close surroundings of the synchrotron-emitting Wolf-Rayet shell G2.4+1.4.
KW  - shock waves
KW  - methods: numerical
KW  - circumstellar matter
KW  - stars: massive
Y1  - 2020
U6  - https://doi.org/10.1093/mnras/staa554
SN  - 0035-8711
SN  - 1365-2966
VL  - 493
IS  - 3
SP  - 3548
EP  - 3564
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Meyer, Dominique M.-A.
A1  - Pohl, Martin
A1  - Petrov, M.
A1  - Egberts, Kathrin
T1  - Mixing of materials in magnetized core-collapse supernova remnants
JF  - Monthly notices of the Royal Astronomical Society
N2  - Core-collapse supernova remnants are structures of the interstellar medium (ISM) left behind the explosive death of most massive stars ( ?40 M-?). Since they result in the expansion of the supernova shock wave into the gaseous environment shaped by the star's wind history, their morphology constitutes an insight into the past evolution of their progenitor star. Particularly, fast-mo ving massiv e stars can produce asymmetric core-collapse superno va remnants. We inv estigate the mixing of materials in core-collapse supernova remnants generated by a moving massive 35 M-? star, in a magnetized ISM. Stellar rotation and the wind magnetic field are time-dependently included into the models which follow the entire evolution of the stellar surroundings from the zero-age main-sequence to 80 kyr after the supernova explosion. It is found that very little main-sequence material is present in remnants from moving stars, that the Wolf-Rayet wind mixes very efficiently within the 10 kyr after the explosion, while the red supergiant material is still unmixed by 30 per cent within 50 kyr after the supernova. Our results indicate that the faster the stellar motion, the more complex the internal organization of the supernova remnant and the more ef fecti ve the mixing of ejecta therein. In contrast, the mixing of stellar wind material is only weakly affected by progenitor motion, if at all.
KW  - ISM;supernova remnants
KW  - (magnetohydrodynamics) MHD
KW  - stars evolution
KW  - stars: massive
Y1  - 2023
U6  - https://doi.org/10.1093/mnras/stad906
SN  - 0035-8711
SN  - 1365-2966
VL  - 521
IS  - 4
SP  - 5354
EP  - 5371
PB  - Oxford Univ. Press
CY  - Oxford
ER  -