@article{54867,
  abstract     = {{<jats:p>
Artificial leaves could be the breakthrough technology to overcome the limitations of storage and mobility through the synthesis of chemical fuels from sunlight, which will be an essential component of a sustainable future energy system. However, the realization of efficient solar‐driven artificial leaf structures requires integrated specialized materials such as semiconductor absorbers, catalysts, interfacial passivation, and contact layers. To date, no competitive system has emerged due to a lack of scientific understanding, knowledge‐based design rules, and scalable engineering strategies. Herein, competitive artificial leaf devices for water splitting, focusing on multiabsorber structures to achieve solar‐to‐hydrogen conversion efficiencies exceeding 15%, are discussed. A key challenge is integrating photovoltaic and electrochemical functionalities in a single device. Additionally, optimal electrocatalysts for intermittent operation at photocurrent densities of 10–20 mA cm<jats:sup>−2</jats:sup> must be immobilized on the absorbers with specifically designed interfacial passivation and contact layers, so‐called buried junctions. This minimizes voltage and current losses and prevents corrosive side reactions. Key challenges include understanding elementary steps, identifying suitable materials, and developing synthesis and processing techniques for all integrated components. This is crucial for efficient, robust, and scalable devices. Herein, corresponding research efforts to produce green hydrogen with unassisted solar‐driven (photo‐)electrochemical devices are discussed and reported.</jats:p>}},
  author       = {{Hannappel, Thomas and Shekarabi, Sahar and Jaegermann, Wolfram and Runge, Erich and Hofmann, Jan Philipp and van de Krol, Roel and May, Matthias M. and Paszuk, Agnieszka and Hess, Franziska and Bergmann, Arno and Bund, Andreas and Cierpka, Christian and Dreßler, Christian and Dionigi, Fabio and Friedrich, Dennis and Favaro, Marco and Krischok, Stefan and Kurniawan, Mario and Lüdge, Kathy and Lei, Yong and Roldán Cuenya, Beatriz and Schaaf, Peter and Schmidt‐Grund, Rüdiger and Schmidt, Wolf Gero and Strasser, Peter and Unger, Eva and Vasquez Montoya, Manuel F. and Wang, Dong and Zhang, Hongbin}},
  issn         = {{2367-198X}},
  journal      = {{Solar RRL}},
  number       = {{11}},
  publisher    = {{Wiley}},
  title        = {{{Integration of Multijunction Absorbers and Catalysts for Efficient Solar‐Driven Artificial Leaf Structures: A Physical and Materials Science Perspective}}},
  doi          = {{10.1002/solr.202301047}},
  volume       = {{8}},
  year         = {{2024}},
}

@article{54868,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>Most properties of solid materials are defined by their internal electric field and charge density distributions which so far are difficult to measure with high spatial resolution. Especially for 2D materials, the atomic electric fields influence the optoelectronic properties. In this study, the atomic‐scale electric field and charge density distribution of WSe<jats:sub>2</jats:sub> bi‐ and trilayers are revealed using an emerging microscopy technique, differential phase contrast (DPC) imaging in scanning transmission electron microscopy (STEM). For pristine material, a higher positive charge density located at the selenium atomic columns compared to the tungsten atomic columns is obtained and tentatively explained by a coherent scattering effect. Furthermore, the change in the electric field distribution induced by a missing selenium atomic column is investigated. A characteristic electric field distribution in the vicinity of the defect with locally reduced magnitudes compared to the pristine lattice is observed. This effect is accompanied by a considerable inward relaxation of the surrounding lattice, which according to first principles DFT calculation is fully compatible with a missing column of Se atoms. This shows that DPC imaging, as an electric field sensitive technique, provides additional and remarkable information to the otherwise only structural analysis obtained with conventional STEM imaging.</jats:p>}},
  author       = {{Groll, Maja and Bürger, Julius and Caltzidis, Ioannis and Jöns, Klaus D. and Schmidt, Wolf Gero and Gerstmann, Uwe and Lindner, Jörg K. N.}},
  issn         = {{1613-6810}},
  journal      = {{Small}},
  publisher    = {{Wiley}},
  title        = {{{DFT‐Assisted Investigation of the Electric Field and Charge Density Distribution of Pristine and Defective 2D WSe<sub>2</sub> by Differential Phase Contrast Imaging}}},
  doi          = {{10.1002/smll.202311635}},
  year         = {{2024}},
}

@article{60582,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>The current efficiency records for generating green hydrogen via solar water splitting are held by indium phosphide (InP)‐based photo‐absorbers, protected by TiO<jats:sub>2</jats:sub> layers grown through atomic layer deposition (ALD). InP is also a leading material for photonic integrated circuits and computing, where ultrafast near‐surface behavior is key. A previous study described electronic pathways at the phosphorus‐rich (P‐rich) surface of p‐doped InP(100) using time‐resolved two‐photon photoemission (tr‐2PPE) spectroscopy. Here, the intricate electron pathways of the P‐rich InP surface modified with ALD‐deposited TiO<jats:sub>2</jats:sub> are explored. Photoexcited bulk InP electrons migrate through a bulk‐to‐surface transition cluster of states and surface states and inject into the TiO<jats:sub>2</jats:sub> conduction band (CB). Energy levels and occupation dynamics of CB states in P‐rich InP and TiO<jats:sub>2</jats:sub> adlayers are observed, with discrete states preserved up to 10 nm TiO<jats:sub>2</jats:sub> deposition. Thermalization lifetimes of excited electrons &gt; 0.8 eV above the InP conduction band minimum (CBM) are preserved for layer thicknesses up to 2.5 nm. Annealing at 300 °C to achieve crystalline TiO<jats:sub>2</jats:sub> reconstructions destroys interfacial states, affecting charge transfer. These observations enable innovative engineering of the P‐rich InP/TiO<jats:sub>2</jats:sub> heterointerface, opening new possibilities for studying hot‐carrier extraction, adsorbate effects, surface plasmons, and improving photovoltaic and PEC water‐splitting devices.</jats:p>}},
  author       = {{Diederich, Jonathan and Rojas, Jennifer Velazquez and Paszuk, Agnieszka and Pour, Mohammad Amin Zare and Höhn, Christian and Ruiz Alvarado, Isaac Azahel and Schwarzburg, Klaus and Ostheimer, David and Eichberger, Rainer and Schmidt, Wolf Gero and Hannappel, Thomas and van de Krol, Roel and Friedrich, Dennis}},
  issn         = {{1616-301X}},
  journal      = {{Advanced Functional Materials}},
  number       = {{49}},
  publisher    = {{Wiley}},
  title        = {{{Ultrafast Electron Dynamics at the P‐rich Indium Phosphide/TiO<sub>2</sub> Interface}}},
  doi          = {{10.1002/adfm.202409455}},
  volume       = {{34}},
  year         = {{2024}},
}

@article{54856,
  abstract     = {{<jats:title>Abstract</jats:title>
               <jats:p>Theoretical spectroscopy based on double perturbation theory is typically challenged by systems with large orbital hyperfine splitting. Therefore, we here derive a rigorous, non-perturbative scheme starting from Dirac’s equation which allows to calculate the contribution of the orbital HFI for complex structures including heavy atoms with strong spin-orbit coupling (SOC). Using the PAW formalism, the method has been implemented in the software package Quantum ESPRESSO. We show that the ‘orbital part’ actually scales with SOC strength if orbital quenching is hindered by low local symmetry, i.e. in case of dimers or atoms at surfaces. This holds true in particular when the unpaired electron is localized in quasi-atomic <jats:italic>p</jats:italic>-like orbitals. Here, the orbital part is by far not negligible, but becomes dominant by surpassing the dipolar contribution by a factor of five.</jats:p>}},
  author       = {{Franzke, Katharina and Schmidt, Wolf Gero and Gerstmann, Uwe}},
  issn         = {{1742-6588}},
  journal      = {{Journal of Physics: Conference Series}},
  number       = {{1}},
  publisher    = {{IOP Publishing}},
  title        = {{{Relativistic calculation of the orbital hyperfine splitting in complex microscopic structures}}},
  doi          = {{10.1088/1742-6596/2701/1/012094}},
  volume       = {{2701}},
  year         = {{2024}},
}

@article{54866,
  author       = {{Diederich, Jonathan and Velasquez Rojas, Jennifer and Zare Pour, Mohammad Amin and Ruiz Alvarado, Isaac Azahel and Paszuk, Agnieszka and Sciotto, Rachele and Höhn, Christian and Schwarzburg, Klaus and Ostheimer, David and Eichberger, Rainer and Schmidt, Wolf Gero and Hannappel, Thomas and van de Krol, Roel and Friedrich, Dennis}},
  issn         = {{0002-7863}},
  journal      = {{Journal of the American Chemical Society}},
  number       = {{13}},
  pages        = {{8949--8960}},
  publisher    = {{American Chemical Society (ACS)}},
  title        = {{{Unraveling Electron Dynamics in p-type Indium Phosphide (100): A Time-Resolved Two-Photon Photoemission Study}}},
  doi          = {{10.1021/jacs.3c12487}},
  volume       = {{146}},
  year         = {{2024}},
}

@article{54855,
  abstract     = {{<jats:p>Density-functional theory calculations on P-rich InP(001):H surfaces are presented. Depending on temperature, pressure and substrate doping, hydrogen desorption or adsorption will occur and influence the surface electronic properties. For p-doped samples, the charge transition levels of the P dangling bond defects resulting from H desorption will lead to Fermi level pinning in the lower half of the band gap. This explains recent experimental data. For n-doped substrates, H-deficient surfaces are the ground-state structure. This will lead to Fermi level pinning below the bulk conduction band minimum. Surface defects resulting from the adsorption of additional hydrogen can be expected as well, but affect the surface electronic properties less than H desorption.</jats:p>}},
  author       = {{Sciotto, Rachele and Ruiz Alvarado, Isaac Azahel and Schmidt, Wolf Gero}},
  issn         = {{2571-9637}},
  journal      = {{Surfaces}},
  number       = {{1}},
  pages        = {{79--87}},
  publisher    = {{MDPI AG}},
  title        = {{{Substrate Doping and Defect Influence on P-Rich InP(001):H Surface Properties}}},
  doi          = {{10.3390/surfaces7010006}},
  volume       = {{7}},
  year         = {{2024}},
}

@article{54869,
  author       = {{Pfnür, H. and Tegenkamp, C. and Sanna, S. and Jeckelmann, E. and Horn-von Hoegen, M. and Bovensiepen, U. and Esser, N. and Schmidt, Wolf Gero and Dähne, M. and Wippermann, S. and Bechstedt, F. and Bode, M. and Claessen, R. and Ernstorfer, R. and Hogan, C. and Ligges, M. and Pucci, A. and Schäfer, J. and Speiser, E. and Wolf, M. and Wollschläger, J.}},
  issn         = {{0167-5729}},
  journal      = {{Surface Science Reports}},
  number       = {{2}},
  publisher    = {{Elsevier BV}},
  title        = {{{Atomic wires on substrates: Physics between one and two dimensions}}},
  doi          = {{10.1016/j.surfrep.2024.100629}},
  volume       = {{79}},
  year         = {{2024}},
}

@article{54865,
  author       = {{Krenz, Marvin and Gerstmann, Uwe and Schmidt, Wolf Gero}},
  issn         = {{0031-9007}},
  journal      = {{Physical Review Letters}},
  number       = {{7}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Defect-Assisted Exciton Transfer across the Tetracene-Si(111):H Interface}}},
  doi          = {{10.1103/physrevlett.132.076201}},
  volume       = {{132}},
  year         = {{2024}},
}

@article{62868,
  abstract     = {{<jats:p>We theoretically investigate strategies for the deterministic creation of trains of time-bin entangled photons using an individual quantum emitter described by a Λ-type electronic system. We explicitly demonstrate the theoretical generation of linear cluster states with substantial numbers of entangled photonic qubits in full microscopic numerical simulations. The underlying scheme is based on the manipulation of ground state coherences through precise optical driving. One important finding is that the most easily accessible quality metrics, the achievable rotation fidelities, fall short in assessing the actual quantum correlations of the emitted photons in the face of losses. To address this, we explicitly calculate stabilizer generator expectation values as a superior gauge for the quantum properties of the generated many-photon state. With widespread applicability in other emitter and excitation–emission schemes also, our work lays the conceptual foundations for an in-depth practical analysis of time-bin entanglement based on full numerical simulations with predictive capabilities for realistic systems and setups, including losses and imperfections. The specific results shown in the present work illustrate that with controlled minimization of losses and realistic system parameters for quantum-dot type systems, useful linear cluster states of significant lengths can be generated in the calculations, discussing the possibility of scalability for quantum information processing endeavors.</jats:p>}},
  author       = {{Bauch, David and Köcher, Nikolas and Heinisch, Nils and Schumacher, Stefan}},
  issn         = {{2835-0103}},
  journal      = {{APL Quantum}},
  number       = {{3}},
  publisher    = {{AIP Publishing}},
  title        = {{{Time-bin entanglement in the deterministic generation of linear photonic cluster states}}},
  doi          = {{10.1063/5.0214197}},
  volume       = {{1}},
  year         = {{2024}},
}

@article{63048,
  title        = {{{High-throughput antibody screening with high-quality factor nanophotonics and bioprinting}}},
  doi          = {{10.48550/ARXIV.2411.18557}},
  year         = {{2024}},
}

@misc{63047,
  author       = {{Güsken, Nicholas Alexander}},
  title        = {{{Schottky-barrier type infrared photodetector }}},
  year         = {{2024}},
}

@article{63044,
  author       = {{Hoessbacher, C. and Baeuerle, B. and Del Medico, N. and De Leo, E. and Güsken, Nicholas Alexander and Heni, W. and Langenbach, A. and Tedaldi, V.}},
  issn         = {{2732-4494}},
  journal      = {{IET Conference Proceedings}},
  number       = {{34}},
  pages        = {{1606--1608}},
  publisher    = {{Institution of Engineering and Technology (IET)}},
  title        = {{{Plasmonic modulators: bringing a new light to silicon}}},
  doi          = {{10.1049/icp.2023.2642}},
  volume       = {{2023}},
  year         = {{2024}},
}

@article{63049,
  author       = {{Güsken, Nicholas Alexander and Brongersma, Mark L.}},
  issn         = {{2791-1748}},
  journal      = {{Photonics Insights}},
  number       = {{4}},
  publisher    = {{Shanghai Institute of Optics and Fine Mechanics}},
  title        = {{{Electrifying the field of metasurface optics}}},
  doi          = {{10.3788/pi.2024.c08}},
  volume       = {{3}},
  year         = {{2024}},
}

@article{46573,
  abstract     = {{<jats:p>An ultra-fast change of the absorption onset for zincblende gallium-nitride (zb-GaN) (fundamental bandgap: 3.23 eV) is observed by investigating the imaginary part of the dielectric function using time-dependent femtosecond pump–probe spectroscopic ellipsometry between 2.9 and 3.7 eV. The 266 nm (4.66 eV) pump pulses induce a large electron–hole pair concentration up to 4×1020cm−3, which shift the transition energy between conduction and valence bands due to many-body effects up to ≈500 meV. Here, the absorption onset increases due to band filling while the bandgap renormalization at the same time decreases the bandgap. Additionally, the absorption of the pump-beam creates a free-carrier profile within the 605 nm zb-GaN layer with high free-carrier concentrations at the surface, and low concentrations at the interface to the substrate. This leads to varying optical properties from the sample surface (high transition energy) to substrate (low transition energy), which are taken into account by grading analysis for an accurate description of the experimental data. For this, a model describing the time- and position-dependent free-carrier concentration is formulated by considering the relaxation, recombination, and diffusion of those carriers. We provide a quantitative analysis of optical experimental data (ellipsometric angles Ψ and Δ) as well as a plot for the time-dependent change of the imaginary part of the dielectric function.</jats:p>}},
  author       = {{Baron, Elias and Goldhahn, Rüdiger and Espinoza, Shirly and Zahradník, Martin and Rebarz, Mateusz and Andreasson, Jakob and Deppe, Michael and As, Donat Josef and Feneberg, Martin}},
  issn         = {{0021-8979}},
  journal      = {{Journal of Applied Physics}},
  keywords     = {{General Physics and Astronomy}},
  number       = {{7}},
  publisher    = {{AIP Publishing}},
  title        = {{{Time-resolved pump–probe spectroscopic ellipsometry of cubic GaN. I. Determination of the dielectric function}}},
  doi          = {{10.1063/5.0153091}},
  volume       = {{134}},
  year         = {{2023}},
}

@article{49117,
  author       = {{Scharwald, D. and Meier, T. and Sharapova, P. R.}},
  issn         = {{2643-1564}},
  journal      = {{Physical Review Research}},
  keywords     = {{General Physics and Astronomy}},
  number       = {{4}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Phase sensitivity of spatially broadband high-gain <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>SU</mml:mi><mml:mo>(</mml:mo><mml:mn>1</mml:mn><mml:mo>,</mml:mo><mml:mn>1</mml:mn><mml:mo>)</mml:mo></mml:mrow></mml:math> interferometers}}},
  doi          = {{10.1103/physrevresearch.5.043158}},
  volume       = {{5}},
  year         = {{2023}},
}

@article{49609,
  abstract     = {{<jats:p>The alignment of liquid crystals on surfaces plays a central role in optimizing their performances. In this work, a cutting-edge nano-lithography-based method to control the local orientation of a thermotropic liquid crystal is applied to easily available commercial standard materials and evaluated. Parallel nanogrooves on a substrate, created through 3D nanoprinting in a negative-tone photoresin optimized for two-photon polymerization are used for this purpose. Azimuthal anchoring energies of the order from 10<jats:sup>−6</jats:sup> J/m<jats:sup>2</jats:sup> to 10<jats:sup>−5</jats:sup> J/m<jats:sup>2</jats:sup> are found, depending on the spacing, width and depth of the grooves. In part, these values are larger than those reported previously for another photopolymer. Both uniform alignment and spatial patterns of different alignment directions can be realized. Electro-optic studies confirm the suitability of the method for electrically addressable photonic applications and indicate strong polar anchoring.</jats:p>}},
  author       = {{Zhang, Bingru and Plidschun, Malte and Schmidt, Markus A. and Kitzerow, Heinz-Siegfried}},
  issn         = {{2159-3930}},
  journal      = {{Optical Materials Express}},
  keywords     = {{Electronic, Optical and Magnetic Materials}},
  number       = {{12}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Anchoring and electro-optic switching of liquid crystals on nano-structured surfaces fabricated by two-photon based nano-printing}}},
  doi          = {{10.1364/ome.503100}},
  volume       = {{13}},
  year         = {{2023}},
}

@article{43440,
  author       = {{Zhang, Bingru and Nguyen, Linh and Martens, Kevin and Heuer-Jungemann, Amelie and Philipp, Julian and Kempter, Susanne and Rädler, Joachim O. and Liedl, Tim and Kitzerow, Heinz-Siegfried}},
  issn         = {{0267-8292}},
  journal      = {{Liquid Crystals}},
  keywords     = {{Condensed Matter Physics, General Materials Science, General Chemistry}},
  number       = {{7-10}},
  pages        = {{1243--1251}},
  publisher    = {{Informa UK Limited}},
  title        = {{{Luminescent DNA-origami nano-rods dispersed in a lyotropic chromonic liquid crystal}}},
  doi          = {{10.1080/02678292.2023.2188494}},
  volume       = {{50}},
  year         = {{2023}},
}

@article{48599,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>The biexciton‐exciton emission cascade commonly used in quantum‐dot systems to generate polarization entanglement yields photons with intrinsically limited indistinguishability. In the present work, it focuses on the generation of pairs of photons with high degrees of polarization entanglement and simultaneously high indistinguishability. It achieves this goal by selectively reducing the biexciton lifetime with an optical resonator. It demonstrates that a suitably tailored circular Bragg reflector fulfills the requirements of sufficient selective Purcell enhancement of biexciton emission paired with spectrally broad photon extraction and twofold degenerate optical modes. The in‐depth theoretical study combines (i) the optimization of realistic photonic structures solving Maxwell's equations from which model parameters are extracted as input for (ii) microscopic simulations of quantum‐dot cavity excitation dynamics with full access to photon properties. It reports non‐trivial dependencies on system parameters and use the predictive power of the combined theoretical approach to determine the optimal range of Purcell enhancement that maximizes indistinguishability and entanglement to near unity values, here specifically for the telecom C‐band at 1550 nm.</jats:p>}},
  author       = {{Bauch, David and Siebert, Dustin and Jöns, Klaus and Förstner, Jens and Schumacher, Stefan}},
  issn         = {{2511-9044}},
  journal      = {{Advanced Quantum Technologies}},
  keywords     = {{tet_topic_qd}},
  publisher    = {{Wiley}},
  title        = {{{On‐Demand Indistinguishable and Entangled Photons Using Tailored Cavity Designs}}},
  doi          = {{10.1002/qute.202300142}},
  year         = {{2023}},
}

@unpublished{43246,
  abstract     = {{The biexciton-exciton emission cascade commonly used in quantum-dot systems to generate polarization entanglement yields photons with intrinsically limited indistinguishability. In the present work we focus on the generation of pairs of photons with high degrees of polarization entanglement and simultaneously high indistinguishibility. We achieve this goal by selectively reducing the biexciton lifetime with an optical resonator. We demonstrate that a suitably tailored circular Bragg reflector fulfills the requirements of sufficient selective Purcell enhancement of biexciton emission paired with spectrally broad photon extraction and two-fold degenerate optical modes. Our in-depth theoretical study combines (i) the optimization of realistic photonic structures solving Maxwell's equations from which model parameters are extracted as input for (ii) microscopic simulations of quantum-dot cavity excitation dynamics with full access to photon properties. We report non-trivial dependencies on system parameters and use the predictive power of our combined theoretical approach to determine the optimal range of Purcell enhancement that maximizes indistinguishability and entanglement to near unity values in the telecom C-band at $1550\,\mathrm{nm}$.}},
  author       = {{Bauch, David and Siebert, Dustin and Jöns, Klaus and Förstner, Jens and Schumacher, Stefan}},
  keywords     = {{tet_topic_phc, tet_topic_qd}},
  title        = {{{On-demand indistinguishable and entangled photons at telecom frequencies using tailored cavity designs}}},
  year         = {{2023}},
}

@article{52122,
  author       = {{Ali, Usman and Holthaus, Martin and Meier, Torsten}},
  issn         = {{2643-1564}},
  journal      = {{Physical Review Research}},
  keywords     = {{General Physics and Astronomy}},
  number       = {{4}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Chirped Bloch-harmonic oscillations in a parametrically forced optical lattice}}},
  doi          = {{10.1103/physrevresearch.5.043152}},
  volume       = {{5}},
  year         = {{2023}},
}