Florian Ruske

@helmholtz-berlin.de

Novel Materials and interfaces for photovoltaic solar cells
Helmholtz-Zentrum Berlin



                       

https://researchid.co/florian.ruske

RESEARCH, TEACHING, or OTHER INTERESTS

Surfaces, Coatings and Films, Renewable Energy, Sustainability and the Environment, Electronic, Optical and Magnetic Materials

83

Scopus Publications

2719

Scholar Citations

26

Scholar h-index

51

Scholar i10-index

Scopus Publications

  • Description of excitonic absorption using the Sommerfeld enhancement factor and band-fluctuations
    K Lizárraga, E Serquen, P Llontop, L A Enrique, M Piñeiro, E Perez, A Tejada, F Ruske, L Korte, and J A Guerra
    IOP Publishing
    Abstract One of the challenges of excitonic materials is the accurate determination of the exciton binding energy and bandgap from optical measurements. The difficulty arises from the overlap of the discrete and continuous excitonic absorption at the band edge. Many researches have modeled the shape of the absorption edge of such materials on the seminal formulation proposed by Elliott in 1957 (Phys. Rev. 108 1384–9) and its several modifications such as non-parabolic bands, magnetic potentials and electron–hole-polaron interactions. However, exciton binding energies obtained from optical absorption often vary strongly depending on the chosen ‘Elliott formula’. Here, we propose an alternative and rather simple approach, which has previously been successful in the determination of the optical bandgap of amorphous, direct and indirect semiconductors, based on the band-fluctuations (BFs) model. In this model, the fluctuations due to disorder, temperature or lattice vibrations give rise to the well known exponential shape of band tail states. The formulation results in an analytic equation for the fundamental absorption with 6 parameters only. To test it, the binding energy and optical bandgap of GaAs and the family of tri-halide perovskites ( MAPbX 3 ), X = Br , I , Cl , over a wide range of temperatures, are obtained by fitting the modified Elliott model. The results for the bandgap, linewidth and exciton binding energy are in good agreement with reports based on non-optical measurements. Moreover, due to the polar nature of perovskites, the retrieved binding energies can be compared with those computed with a model proposed by Kane (1978 Phys. Rev. B 18 6849). In the latter model, the exciton is surrounded by a cloud of virtual phonons interacting via the Frölich interaction. As a consequence, the upper bound for the binding energy of the exciton-polaron system can be estimated. These results are in good agreement with the optical parameters obtained with the proposed Elliott equation including BFs.

  • Texture-Enhanced Mechanical Stability of Transparent Electrodes for Flexible Optoelectronics with Near-Infrared Response
    Simon Rieckhoff, Florian Riesebeck, Marcos Soldera, Katja Mayer‐Stillrich, Qiong Wang, Florian Ruske, Andrés Fabián Lasagni, and Christiane Becker
    Wiley
    AbstractTransparent electrodes with high conductivity and mechanical robustness are essential for flexible opto‐electronic applications. Indium tin oxide (ITO) single layers have long been considered as unsuitable for flexible applications due to their brittleness. Here, it is shown that their mechanical stability can be substantially enhanced by texturing the flexible substrate. First, the opto‐electronic performance of single ITO layers and ITO/Ag/ITO stacks on polyethylene terephthalate (PET) foils is evaluated numerically by means of Haacke's figure‐of‐merit. Single ITO layers are found to be the electrode of choice for applications with a near‐infrared response due to their superior transparency. Following this, the sheet resistance of ITO layers is experimentally investigated on textured PET upon deformation parallel and perpendicular to a 1D texture grating. An “accordion‐like” deformation perpendicular to the grating and high texture aspect ratios are shown to avoid crack formation and loss of conductivity in the ITO. Simulations prove the considerably reduced occurrence of mechanical stress in this case. It is further experimentally demonstrated that texturing foils increase transmittance and haze. The enhanced mechanical robustness and optical performance by using textured foils make single ITO layers promising candidates for flexible opto‐electronic applications with a near‐infrared response, such as all‐perovskite tandem solar cells, thermal sensors, and photodetectors.

  • Seed Layers for Wide-Band Gap Coevaporated Perovskite Solar Cells: CsCl Regulates Band Gap and Reduces Process Variability
    Viktor Škorjanc, Aleksandra Miaskiewicz, Marcel Roß, Suresh Maniyarasu, Stefanie Severin, Matthew R. Leyden, Philippe Holzhey, Florian Ruske, Lars Korte, and Steve Albrecht
    American Chemical Society (ACS)

  • Transient grating spectroscopy on a DyCo<inf>5</inf> thin film with femtosecond extreme ultraviolet pulses
    Victor Ukleev, Ludmila Leroy, Riccardo Mincigrucci, Dario De Angelis, Danny Fainozzi, Nupur Ninad Khatu, Ettore Paltanin, Laura Foglia, Filippo Bencivenga, Chen Luo,et al.
    AIP Publishing
    Surface acoustic waves (SAWs) are excited by femtosecond extreme ultraviolet (EUV) transient gratings (TGs) in a room-temperature ferrimagnetic DyCo5 alloy. TGs are generated by crossing a pair of EUV pulses from a free electron laser with the wavelength of 20.8 nm matching the Co M-edge, resulting in a SAW wavelength of Λ = 44 nm. Using the pump-probe transient grating scheme in reflection geometry, the excited SAWs could be followed in the time range of −10 to 100 ps in the thin film. Coherent generation of TGs by ultrafast EUV pulses allows to excite SAW in any material and to investigate their couplings to other dynamics, such as spin waves and orbital dynamics. In contrast, we encountered challenges in detecting electronic and magnetic signals, potentially due to the dominance of the larger SAW signal and the weakened reflection signal from underlying layers. A potential solution for the latter challenge involves employing soft x-ray probes, albeit introducing additional complexities associated with the required grazing incidence geometry.

  • Development of direct current magnetron sputtered TiO<inf>2−x</inf> thin films as buffer layers for copper indium gallium diselenide based solar cells
    David Stock, Nikolaus Weinberger, Florian Ruske, Leander Haug, Martina Harnisch, and Roman Lackner
    Elsevier BV

  • Disentangling the effect of the hole-transporting layer, the bottom, and the top device on the fill factor in monolithic CIGSe-perovskite tandem solar cells by using spectroscopic and imaging tools
    I Kafedjiska, G Farias Basulto, F Ruske, N Maticiuc, T Bertram, C A Kaufmann, R Schlatmann, and I Lauermann
    IOP Publishing
    Abstract We present monolithic copper–indium–gallium–diselenide (Cu(In,Ga)Se2, CIGSe)-perovskite tandem solar cells with air- or N2-transferred NiO x :Cu with or without self-assembled monolayer (SAM) as a hole-transporting layer (HTL). A champion efficiency of 23.2%, open-circuit voltage (V o c ) of 1.69 V, and a fill factor (FF) of 78.3% are achieved for the tandem with N2-transferred NiO x :Cu + SAM. The samples with air-transferred NiO x :Cu + SAM have V o c and FF losses, while those without SAM are heavily shunted. We find via x-ray and UV photoelectron spectroscopy that the air exposure leads to non-negligible loss in the Ni2+ species and changes in the NiO x :Cu’s work function and valence band maxima, both of which can negatively impact the V o c and the FF of the tandems. Furthermore, by performing dark lock-in thermography, photoluminescence (PL), and scanning electron microscopy studies, we are able to detect various morphological defects in the tandems with poor performance, such as ohmic shunts originating from defects in the bottom CIGSe cell, or from cracking/delaminating of the perovskite top cell. Finally, by correlating the detected shunts in the tandems with PL-probed bottom device, we can conclude that not all defects in the bottom device induce ohmic shunts in the tandems since the NiO x :Cu + SAM HTL bi-layer can decouple the growth of the top device from the rough, defect-rich and defect-tolerant bottom device and enable high-performing devices.

  • Reducing sputter damage-induced recombination losses during deposition of the transparent front-electrode for monolithic perovskite/silicon tandem solar cells
    Marlene Härtel, Bor Li, Silvia Mariotti, Philipp Wagner, Florian Ruske, Steve Albrecht, and Bernd Szyszka
    Elsevier BV

  • Slot-Die Coated Triple-Halide Perovskites for Efficient and Scalable Perovskite/Silicon Tandem Solar Cells
    Ke Xu, Amran Al-Ashouri, Zih-Wei Peng, Eike Köhnen, Hannes Hempel, Fatima Akhundova, Jose A. Marquez, Philipp Tockhorn, Oleksandra Shargaieva, Florian Ruske,et al.
    American Chemical Society (ACS)
    Wide bandgap halide perovskite materials show promising potential to pair with silicon bottom cells. To date, most efficient wide bandgap perovskites layers are fabricated by spin-coating, which is difficult to scale up. Here, we report on slot-die coating for an efficient, 1.68 eV wide bandgap triple-halide (3halide) perovskite absorber, (Cs0.22FA0.78)Pb(I0.85Br0.15)3 + 5 mol % MAPbCl3. A suitable solvent system is designed specifically for the slot-die coating technique. We demonstrate that our fabrication route is suitable for tandem solar cells without phase segregation. The slot-die coated wet halide perovskite is dried by a “nitrogen (N2)-knife” with high reproducibility and avoiding antisolvents. We explore varying annealing conditions and identify parameters allowing crystallization of the perovskite film into large grains reducing charge collection losses and enabling higher current density. At 150 °C, an optimized trade-off between crystallization and the PbI2 aggregates on the film’s top surface is found. Thus, we improve the cell stability and performance of both single-junction cells and tandems. Combining the 3halide top cells with a 120 μm thin saw damage etched commercial Czochralski industrial wafer, a 2-terminal monolithic tandem solar cell with a PCE of 25.2% on a 1 cm2 active area is demonstrated with fully scalable processes.

  • Optimization of Silicon Heterojunction Interface Passivation on p- and n-Type Wafers Using Optical Emission Spectroscopy
    Engin Özkol, Philipp Wagner, Florian Ruske, Bernd Stannowski, and Lars Korte
    Wiley
    To increase the efficiency in p‐type wafer‐based silicon heterojunction (SHJ) technology, one of the most crucial challenges is the achievement of excellent surface passivation. Herein, chemical passivation techniques known for n‐type technology are successfully applied on p‐type float–zone (FZ) wafers, and wafer surface passivation quality is correlated with parameters from plasma diagnostics, namely crystallization rate and electron temperature indices. It is shown that plasma ignition at higher powers than deposition powers enhances effective minority carrier lifetimes τeff fourfold for p‐ (0.6–2.1 ms) and sixfold for n‐type (0.6–3.2 ms) wafers while giving opportunity to process under lower electron temperature indices during the nucleation phase. A subsequent hydrogen plasma treatment has a further beneficial effect on chemical passivation, leading to high effective minority carrier lifetimes of 4.5 and 3.1 ms, and implies open‐circuit voltages, i‐VOC, of 735 and 720 mV for p‐ and n‐type wafers, respectively. In particular, cell precursors built on p‐type wafers demonstrate excellent surface passivation with τeff and i‐VOC (4.1 ms and 745 mV). Using these process optimizations, SHJ cells on both p‐ and n‐type wafers are fabricated with efficiencies exceeding 21%.

  • Optoelectrical analysis of TCO+Silicon oxide double layers at the front and rear side of silicon heterojunction solar cells
    Alexandros Cruz, Darja Erfurt, Philipp Wagner, Anna B. Morales-Vilches, Florian Ruske, Rutger Schlatmann, and Bernd Stannowski
    Elsevier BV

  • Hybrid Perovskite Degradation from an Optical Perspective: A Spectroscopic Ellipsometry Study from the Deep Ultraviolet to the Middle Infrared
    Alvaro Tejada, Sven Peters, Amran Al‐Ashouri, Silver Hamill Turren‐Cruz, Antonio Abate, Steve Albrecht, Florian Ruske, Bernd Rech, Jorge Andrés Guerra, and Lars Korte
    Wiley
    AbstractA quantitative analysis of the thermally induced degradation of various device‐relevant multi‐cation hybrid perovskite films is performed using spectroscopic ellipsometry, for temperatures between 80 and 120 °C. The studied compositions are a triple cation perovskite Cs0.05(MA0.17FA0.83)0.95Pb(Br0.17I0.83)3, a Rb‐containing variant Rb0.05Cs0.05(MA0.17FA0.83)0.90Pb(Br0.17I0.83)3, and a methylammonium‐free Rb0.05Cs0.10FA0.85PbI3 composition. A very wide combined spectral range of 200 nm to 25 μm is covered by combining the data from two separate instruments. The relative changes in organic cation concentrations are quantified from the middle infrared molecular absorption bands, leveraging the use of point‐by‐point fitting for increased sensitivity. Additionally, the formation of PbI2 and non‐perovskite δ‐CsPbI3 phases is evidenced from Bruggemann effective medium fits to the visible and ultraviolet complex refractive indices. Methylammonium is almost completely depleted from the relevant compositions within 100 to 285 min of thermal annealing. The MA‐free perovskite degrades faster at intermediate temperatures, which is attributed to phase instability due to the formation of δ‐CsPbI3 in addition to PbI2.

  • Elucidating the effect of the different buffer layers on the thermal stability of CIGSe solar cells
    Hasan A. Yetkin, Tim Kodalle, Tobias Bertram, Alejandra Villanueva Tovar, Reiner Klenk, Marin Rusu, Josefa Ibaceta-Jana, Florian Ruske, Ibrahim Simsek, Ruslan Muydinov,et al.
    Institute of Electrical and Electronics Engineers (IEEE)
    In this contribution, the impact of thermal stress on Cu(In,Ga)Se<inline-formula><tex-math notation="LaTeX">$_{2}$</tex-math></inline-formula> (CIGSe) thin film photovoltaic devices is investigated. The tolerance of such devices to high temperatures is of particular interest for processing transparent conductive oxides (TCOs) in order to further close the gap to the theoretical efficiency limit and for their potential use as bottom devices in tandem applications in order to overcome the theoretical efficiency limit of single junction solar cells. When CdS-buffered CIGSe high efficiency solar cells are subjected to thermal stress, elemental interdiffusion of Na and Cd between the absorber and the window layers as well as chemical reactions at the CIGSe/CdS interface result in a degraded power conversion efficiency (PCE). Here, we compare the degradation mechanisms of CdS and GaO<inline-formula><tex-math notation="LaTeX">$_{x}$</tex-math></inline-formula> buffered CIGSe solar cells under thermal stress. A model explaining the observed degradation behaviors is proposed.

  • Energy-level alignment tuning at tetracene/c-Si interfaces
    Jens Niederhausen, Rowan W. MacQueen, Engin Özkol, Clemens Gersmann, Moritz H. Futscher, Martin Liebhaber, Dennis Friedrich, Mario Borgwardt, Katherine A. Mazzio, Patrick Amsalem,et al.
    American Chemical Society (ACS)
    The rational combination of tetracene (Tc) with crystalline silicon (c-Si) could greatly enhance c-Si solar cell efficiencies via singlet fission. The Tc/c-Si energy-level alignment (ELA) is though...

  • Influence of Silicon Layers on the Growth of ITO and AZO in Silicon Heterojunction Solar Cells
    Alexandros Cruz, Florian Ruske, Alberto Eljarrat, Pawel P. Michalowski, Anna B. Morales-Vilches, Sebastian Neubert, Er-Chien Wang, Christoph T. Koch, Bernd Szyszka, Rutger Schlatmann,et al.
    Institute of Electrical and Electronics Engineers (IEEE)
    In this article, we report on the properties of indium tin oxide (ITO) deposited on thin-film silicon layers designed for the application as carrier selective contacts for silicon heterojunction (SHJ) solar cells. We find that ITO deposited on hydrogenated nanocrystalline silicon (nc-Si:H) layers presents a significant drop on electron mobility <inline-formula><tex-math notation="LaTeX">${\\mu} _{{\\rm{e}}}$</tex-math></inline-formula> in comparison to layers deposited on hydrogenated amorphous silicon films (a-Si:H). The nc-Si:H layers are not only found to exhibit a larger crystallinity than a-Si:H, but are also characterized by a considerably increased surface rms roughness. As we can see from transmission electron microscopy (TEM), this promotes the growth of smaller and fractured features in the initial stages of ITO growth. Furthermore, secondary ion mass spectrometry profiles show different penetration depths of hydrogen from the thin film silicon layers into the ITO, which might both influence ITO and device passivation properties. Comparing ITO to aluminum doped zinc oxide (AZO), we find that AZO can actually exhibit superior properties on nc-Si:H layers. We assess the impact of the modified ITO <italic>R</italic><sub>sh</sub> on the series resistance <inline-formula><tex-math notation="LaTeX">$R_{s}$</tex-math></inline-formula> of SHJ solar cells with >23% efficiency for optimized devices. This behavior should be considered when designing solar cells with amorphous or nanocrystalline layers as carrier selective contacts.

  • Advantageous light management in Cu(In,Ga)Se<inf>2</inf> superstrate solar cells
    M.D. Heinemann, F. Ruske, D. Greiner, A.R. Jeong, M. Rusu, B. Rech, R. Schlatmann, and C.A. Kaufmann
    Elsevier BV

  • High mobility In<inf>2</inf>O<inf>3</inf>:H as contact layer for a-Si:H/c-Si heterojunction and μc-Si:H thin film solar cells
    H. Scherg-Kurmes, S. Körner, S. Ring, M. Klaus, L. Korte, F. Ruske, R. Schlatmann, B. Rech, and B. Szyszka
    Elsevier BV

  • Water-assisted nitrogen mediated crystallisation of ZnO films
    R. Muydinov, A. Steigert, S. Schönau, F. Ruske, R. Kraehnert, B. Eckhardt, I. Lauermann, and B. Szyszka
    Elsevier BV

  • Combination of nitrogen mediated crystallisation with post-deposition annealing - Towards ultra-thin ZnO:Al contacts
    R. Muydinov, F. Ruske, S. Neubert, A. Steigert, M. Klaus, S. Selve, G. Köppel, and B. Szyszka
    Elsevier BV

  • Light trapping for a-Si: H/μc-Si: H tandem solar cells using direct pulsed laser interference texturing
    Sven Ring, Sebastian Neubert, Christof Schultz, Sebastian S. Schmidt, Florian Ruske, Bernd Stannowski, Frank Fink, and Rutger Schlatmann
    Wiley
    We present a‐Si:H/µc‐Si:H tandem solar cells on laser textured ZnO:Al front contact layers. Direct pulsed laser interference patterning (DLIP) was used for writing arrays of one‐dimensional micro gratings of submicron period into ZnO:Al films. The laser texture provides good light trapping which is indicated by an increase in short‐circuit current density of 20% of the bottom cell limited device compared to cells on planar ZnO:Al. The open‐circuit voltage of the cells on laser textured ZnO:Al is almost the same as for cells on planar substrates, indicating excellent growth conditions for amorphous and microcrystalline silicon on the U‐shaped grating grooves. DLIP is a simple, single step and industrially applicable method for large area periodic texturing of ZnO:Al thin films. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

  • Improved conversion efficiency of a-Si:H/μc-Si:H thin-film solar cells by using annealed Al-doped zinc oxide as front electrode material
    Sebastian Neubert, Mark Wimmer, Florian Ruske, Sonya Calnan, Onno Gabriel, Bernd Stannowski, Rutger Schlatmann, and Bernd Rech
    Wiley
    ABSTRACTIn recent years, zinc oxide has been investigated as a front electrode material in hydrogenated amorphous silicon/hydrogenated microcrystalline silicon (a‐Si:H/µc‐Si:H) tandem solar cells. Such as for other transparent conducting oxide materials and applications, a proper balancing of transparency and conductivity is necessary. The latter is directly related to the density and the mobility of charge carriers. A high density of charge carriers increases conductivity but leads to a higher absorption of light in the near‐infrared part of the spectrum due to increased free‐carrier absorption. Hence, the only way to achieve high conductivity while keeping the transparency as high as possible relies on an increase of carrier mobility. The carrier density and the mobility of sputtered Al‐doped zinc oxide (ZnO:Al) can be tailored by a sequence of different annealing steps. In this work, we implemented such annealed ZnO:Al films as a front electrode in a‐Si:H/µc‐Si:H tandem solar cells and compared the results with those of reference cells grown on as‐deposited ZnO:Al. We observed an improvement of short‐circuit current density as well as open‐circuit voltage and fill factor. The gain in current density could be attributed to a reduction of both sub‐band‐gap absorption and free‐carrier absorption in the ZnO:Al. The higher open‐circuit voltage and fill factor are indicators of a better device quality of the silicon for cells grown on annealed ZnO:Al. Altogether, the annealing led to an improved initial conversion efficiency of 12.1%, which was a gain of +0.7% in absolute terms. Copyright © 2013 John Wiley &amp; Sons, Ltd.

  • The complex interface chemistry of thin-film silicon/zinc oxide solar cell structures
    D. Gerlach, M. Wimmer, R. G. Wilks, R. Félix, F. Kronast, F. Ruske, and M. Bär
    Royal Society of Chemistry (RSC)
    The interface between solid-phase crystallized phosphorous-doped polycrystalline silicon (poly-Si(n(+))) and aluminum-doped zinc oxide (ZnO:Al) was investigated using spatially resolved photoelectron emission microscopy. We find the accumulation of aluminum in the proximity of the interface. Based on a detailed photoemission line analysis, we also suggest the formation of an interface species. Silicon suboxide and/or dehydrated hemimorphite have been identified as likely candidates. For each scenario a detailed chemical reaction pathway is suggested. The chemical instability of the poly-Si(n(+))/ZnO:Al interface is explained by the fact that SiO2 is more stable than ZnO and/or that H2 is released from the initially deposited a-Si:H during the crystallization process. As a result, Zn (a deep acceptor in silicon) is "liberated" close to the silicon/zinc oxide interface presenting the inherent risk of forming deep defects in the silicon absorber. These could act as recombination centers and thus limit the performance of silicon/zinc oxide based solar cells. Based on this insight some recommendations with respect to solar cell design, material selection, and process parameters are given for further knowledge-based thin-film silicon device optimization.

  • Annealing related changes in near-edge absorption and structural properties of Al-doped ZnO thin films
    S. Schönau, F. Ruske, S. Neubert, and B. Rech
    Wiley
    AbstractIn order to clarify the origin of the previously reported reduction of sub‐band gap absorption of sputtered ZnO:Al films upon thermal annealing and raising deposition temperature, structural characterization using Ra‐man spectroscopy was carried out on various films. Correlation of the Urbach energy to the FWHM of the E(high)2 mode was found. Oxygen addition to the film growth did not result in changes of the Urbach energy, despite pronounced changes of the electrical properties. The results suggest that extended defects, rather than intrinsic point defects, give rise to the sub‐band gap absorption. (© 2014 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

  • Crack formation and Zn diffusion in high-temperature processed poly-Si/ZnO:Al stacks
    Carolin Zachäus, Christiane Becker, Florian Ruske, and Bernd Rech
    Elsevier BV

  • Solution-Processed Crystalline Silicon Thin-Film Solar Cells
    Tobias Sontheimer, Daniel Amkreutz, Katharina Schulz, Paul H. Wöbkenberg, Christian Guenther, Vadym Bakumov, Joachim Erz, Christoph Mader, Stephan Traut, Florian Ruske,et al.
    Wiley
    Dr. T. Sontheimer, Dr. D. Amkreutz, Dr. F. Ruske, Dr. M. Weizman, Dr. A. Schnegg, Prof. Dr. B. Rech Helmholtz Zentrum Berlin Silicon Photovoltaics Kekuléstr. 5 , Berlin 12489 , Germany E-mail: tobias.sontheimer@helmholtz-berlin.de K. Schulz, Dr. P. H. Wöbkenberg, C. Guenther, Dr. V. Bakumov, J. Erz, Dr. C. Mader, Dr. S. Traut, Dr. M. Patz, Dr. M. Trocha, Dr. O. Wunnicke Evonik Industries AG Paul-Baumann Str. 1 , Marl 45772 , Germany


RECENT SCHOLAR PUBLICATIONS

  • Description of excitonic absorption using the Sommerfeld enhancement factor and band-fluctuations
    K Lizrraga, E Serquen, P Llontop, LA Enrique, M Pieiro, E Perez, ...
    Journal of Physics D: Applied Physics 58 (6), 065102 2024

  • Seed Layers for Wide-Band Gap Coevaporated Perovskite Solar Cells: CsCl Regulates Band Gap and Reduces Process Variability
    V Škorjanc, A Miaskiewicz, M Ro, S Maniyarasu, S Severin, ...
    ACS Energy Letters 9 (11), 5639-5646 2024

  • How to accelerate outdoor ageing of perovskite solar cells by indoor testing
    A Musiienko, NT Hartono, U Erdil, Z Nia, M Khenkin, H Kbler, ...
     2024

  • Enhanced Electron Extraction in Co-Doped TiO2 Quantified by Drift-Diffusion Simulation for Stable CsPbI3 Solar Cells
    TW Gries, D Regaldo, H Koebler, TNH Putri, GV Sannino, EG Partida, ...
    arXiv preprint arXiv:2403.11982 2024

  • Transient grating spectroscopy on a DyCo5 thin film with femtosecond extreme ultraviolet pulses
    V Ukleev, L Leroy, R Mincigrucci, D Deangelis, D Fainozzi, NN Khatu, ...
    Structural Dynamics 11 (2) 2024

  • Development of direct current magnetron sputtered TiO2− x thin films as buffer layers for copper indium gallium diselenide based solar cells
    D Stock, N Weinberger, F Ruske, L Haug, M Harnisch, R Lackner
    Thin Solid Films 786, 140115 2023

  • Minimizing Sputter Damage-Induced Electrical Losses in Monolithic Perovskite/Silicon Tandem Solar Cells During Deposition of the Transparent Front-Electrode
    M Hrtel, B Li, S Mariotti, P Wagner, F Ruske, S Albrecht, B Szyszka
    2023 IEEE 50th Photovoltaic Specialists Conference (PVSC), 1-1 2023

  • Disentangling the effect of the hole-transporting layer, the bottom, and the top device on the fill factor in monolithic CIGSe-perovskite tandem solar cells by using
    I Kafedjiska, GF Basulto, F Ruske, N Maticiuc, T Bertram, CA Kaufmann, ...
    Journal of Physics: Energy 5 (2), 024014 2023

  • Reducing sputter damage-induced recombination losses during deposition of the transparent front-electrode for monolithic perovskite/silicon tandem solar cells
    M Hrtel, B Li, S Mariotti, P Wagner, F Ruske, S Albrecht, B Szyszka
    Solar Energy Materials and Solar Cells 252, 112180 2023

  • Slot-die coated triple-halide perovskites for efficient and scalable perovskite/silicon tandem solar cells
    K Xu, A Al-Ashouri, ZW Peng, E Köhnen, H Hempel, F Akhundova, ...
    ACS Energy Letters 7 (10), 3600-3611 2022

  • Optimization of Silicon Heterojunction Interface Passivation on p‐and n‐Type Wafers Using Optical Emission Spectroscopy
    E zkol, P Wagner, F Ruske, B Stannowski, L Korte
    physica status solidi (a) 219 (5), 2100511 2022

  • Optoelectrical analysis of TCO+ Silicon oxide double layers at the front and rear side of silicon heterojunction solar cells
    A Cruz, D Erfurt, P Wagner, AB Morales-Vilches, F Ruske, R Schlatmann, ...
    Solar Energy Materials and Solar Cells 236, 111493 2022

  • Hybrid perovskite degradation from an optical perspective: A spectroscopic ellipsometry study from the deep ultraviolet to the middle infrared
    A Tejada, S Peters, A Al‐Ashouri, SH Turren‐Cruz, A Abate, S Albrecht, ...
    Advanced Optical Materials 10 (3), 2101553 2022

  • Elucidating the effect of the different buffer layers on the thermal stability of CIGSe solar cells
    HA Yetkin, T Kodalle, T Bertram, AV Tovar, R Klenk, M Rusu, ...
    IEEE Journal of Photovoltaics 11 (3), 648-657 2021

  • Energy-level alignment tuning at tetracene/c-Si interfaces
    J Niederhausen, RW MacQueen, E Özkol, C Gersmann, MH Futscher, ...
    The Journal of Physical Chemistry C 124 (51), 27867-27881 2020

  • Influence of silicon layers on the growth of ITO and AZO in silicon heterojunction solar cells
    A Cruz, F Ruske, A Eljarrat, PP Michalowski, AB Morales-Vilches, ...
    IEEE Journal of Photovoltaics 10 (2), 703-709 2019

  • Optoelectronic performance of TCO on silicon heterojunction rear-emitter solar cells
    A Cruz, H Berlin, S Neubert, H Berlin, H Berlin, D Erfurt, H Berlin
    Proceedings of the 35th European Photovoltaic Solar Energy Conference and 2018

  • Advantageous light management in Cu (In, Ga) Se2 superstrate solar cells
    MD Heinemann, F Ruske, D Greiner, AR Jeong, M Rusu, B Rech, ...
    Solar Energy Materials and Solar Cells 150, 76-81 2016

  • High mobility In2O3: H as contact layer for a-Si: H/c-Si heterojunction and μc-Si: H thin film solar cells
    H Scherg-Kurmes, S Krner, S Ring, M Klaus, L Korte, F Ruske, ...
    Thin Solid Films 594, 316-322 2015

  • Water-assisted nitrogen mediated crystallisation of ZnO films
    R Muydinov, A Steigert, S Schnau, F Ruske, R Kraehnert, B Eckhardt, ...
    Thin Solid Films 590, 177-183 2015

MOST CITED SCHOLAR PUBLICATIONS

  • Improved electrical transport in Al-doped zinc oxide by thermal treatment
    F Ruske, M Roczen, K Lee, M Wimmer, S Gall, J Hpkes, D Hrunski, ...
    Journal of applied physics 107 (1) 2010
    Citations: 246

  • Towards wafer quality crystalline silicon thin-film solar cells on glass
    J Haschke, D Amkreutz, L Korte, F Ruske, B Rech
    Solar Energy Materials and Solar Cells 128, 190-197 2014
    Citations: 143

  • High power pulsed magnetron sputtering of transparent conducting oxides
    V Sittinger, F Ruske, W Werner, C Jacobs, B Szyszka, DJ Christie
    Thin Solid Films 516 (17), 5847-5859 2008
    Citations: 140

  • Band lineup in amorphous/crystalline silicon heterojunctions and the impact of hydrogen microstructure and topological disorder
    TF Schulze, L Korte, F Ruske, B Rech
    Physical Review B—Condensed Matter and Materials Physics 83 (16), 165314 2011
    Citations: 138

  • Polycrystalline silicon thin-film solar cells on glass
    S Gall, C Becker, E Conrad, P Dogan, F Fenske, B Gorka, KY Lee, B Rau, ...
    Solar Energy Materials and Solar Cells 93 (6-7), 1004-1008 2009
    Citations: 125

  • ZnO: Al films deposited by in-line reactive AC magnetron sputtering for a-Si: H thin film solar cells
    V Sittinger, F Ruske, W Werner, B Szyszka, B Rech, J Hpkes, G Schpe, ...
    Thin Solid Films 496 (1), 16-25 2006
    Citations: 120

  • Optical modeling of free electron behavior in highly doped ZnO films
    F Ruske, A Pflug, V Sittinger, B Szyszka, D Greiner, B Rech
    Thin Solid Films 518 (4), 1289-1293 2009
    Citations: 104

  • Optical characterization of aluminum-doped zinc oxide films by advanced dispersion theories
    A Pflug, V Sittinger, F Ruske, B Szyszka, G Dittmar
    Thin Solid Films 455, 201-206 2004
    Citations: 104

  • Large area ZnO: Al films with tailored light scattering properties for photovoltaic applications
    F Ruske, C Jacobs, V Sittinger, B Szyszka, W Werner
    Thin Solid Films 515 (24), 8695-8698 2007
    Citations: 95

  • Microstructure and photovoltaic performance of polycrystalline silicon thin films on temperature-stable ZnO: Al layers
    C Becker, F Ruske, T Sontheimer, B Gorka, U Bloeck, S Gall, B Rech
    Journal of Applied Physics 106 (8) 2009
    Citations: 72

  • Slot-die coated triple-halide perovskites for efficient and scalable perovskite/silicon tandem solar cells
    K Xu, A Al-Ashouri, ZW Peng, E Köhnen, H Hempel, F Akhundova, ...
    ACS Energy Letters 7 (10), 3600-3611 2022
    Citations: 71

  • Conversion efficiency and process stability improvement of electron beam crystallized thin film silicon solar cells on glass
    D Amkreutz, J Haschke, T Hring, F Ruske, B Rech
    Solar Energy Materials and Solar Cells 123, 13-16 2014
    Citations: 71

  • Improving the electrical and optical properties of DC-sputtered ZnO: Al by thermal post deposition treatments
    M Wimmer, F Ruske, S Scherf, B Rech
    Thin Solid Films 520 (12), 4203-4207 2012
    Citations: 61

  • Optoelectrical analysis of TCO+ Silicon oxide double layers at the front and rear side of silicon heterojunction solar cells
    A Cruz, D Erfurt, P Wagner, AB Morales-Vilches, F Ruske, R Schlatmann, ...
    Solar Energy Materials and Solar Cells 236, 111493 2022
    Citations: 60

  • Hydrogen doping of DC sputtered ZnO: Al films from novel target material
    F Ruske, V Sittinger, W Werner, B Szyszka, KU Van Osten, K Dietrich, ...
    Surface and Coatings Technology 200 (1-4), 236-240 2005
    Citations: 57

  • Influence of damp heat on the optical and electrical properties of Al-doped zinc oxide
    D Greiner, N Papathanasiou, A Pflug, F Ruske, R Klenk
    Thin Solid Films 517 (7), 2291-2294 2009
    Citations: 55

  • Temperature stability of ZnO: Al film properties for poly-Si thin-film devices
    KY Lee, C Becker, M Muske, F Ruske, S Gall, B Rech, M Berginski, ...
    Applied Physics Letters 91 (24), 241911-241911-3 2007
    Citations: 55

  • Damp heat stable doped zinc oxide films
    J Hpkes, JI Owen, M Wimmer, F Ruske, D Greiner, R Klenk, U Zastrow, ...
    Thin Solid Films 555, 48-52 2014
    Citations: 53

  • Reactive deposition of aluminium-doped zinc oxide thin films using high power pulsed magnetron sputtering
    F Ruske, A Pflug, V Sittinger, W Werner, B Szyszka, DJ Christie
    Thin Solid Films 516 (14), 4472-4477 2008
    Citations: 52

  • Influence of hydrogen plasma on the defect passivation of polycrystalline Si thin film solar cells
    B Gorka, B Rau, P Dogan, C Becker, F Ruske, S Gall, B Rech
    Plasma Processes and Polymers 6 (S1), S36-S40 2009
    Citations: 50