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52. A Cu3BHT‐Graphene van der Waals Heterostructure with Strong Interlayer Coupling for Highly Efficient Photoinduced Charge Separation

Author

Wang, Zhiyong, primary, Fu, Shuai, additional, Zhang, Wenjie, additional, Liang, Baokun, additional, Liu, Tsai‐Jung, additional, Hambsch, Mike, additional, Pöhls, Jonas F., additional, Wu, Yufeng, additional, Zhang, Jianjun, additional, Lan, Tianshu, additional, Li, Xiaodong, additional, Qi, Haoyuan, additional, Polozij, Miroslav, additional, Mannsfeld, Stefan C. B., additional, Kaiser, Ute, additional, Bonn, Mischa, additional, Weitz, R. Thomas, additional, Heine, Thomas, additional, Parkin, Stuart S. P., additional, Wang, Hai I., additional, Dong, Renhao, additional, and Feng, Xinliang, additional

Published
2024
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57. Ultraschnelle oberflächenspezifische Spektroskopie von Wasser an einem photoangeregten TiO2‐Modell‐Photokatalysator zur Wasserspaltung

Author

Backus, Ellen H. G., primary, Hosseinpour, Saman, additional, Ramanan, Charusheela, additional, Sun, Shumei, additional, Schlegel, Simon J., additional, Zelenka, Moritz, additional, Jia, Xiaoyu, additional, Gebhard, Maximilian, additional, Devi, Anjana, additional, Wang, Hai I., additional, and Bonn, Mischa, additional

Published
2024
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59. Ice interfaces: general discussion

Author

Advincula, Xavier R., primary, Backus, Ellen H. G., additional, Bartels-Rausch, Thorsten, additional, Benaglia, Simone, additional, Ben Ari, Gil, additional, Blow, Katarina E., additional, Bonn, Mischa, additional, Bui, Anna T., additional, Cox, Stephen J., additional, Della Pia, Flaviano, additional, Diebold, Ulrike, additional, Finney, Aaron R., additional, Franceschi, Giada, additional, Fumagalli, Laura, additional, Goel, Gaurav, additional, Hayton, John A., additional, Holdship, Charlie, additional, Jiang, Ying, additional, Jin, Di, additional, Kapil, Venkat, additional, Kavokine, Nikita, additional, Koga, Kenichiro, additional, Laage, Damien, additional, Lahav, Meir, additional, Miao, Shurui, additional, Michaelides, Angelos, additional, Mohandas, Nandita, additional, Morgenstern, Karina, additional, Mukherjee, Taritra, additional, Nagata, Yuki, additional, Olvera de la Cruz, Monica, additional, Pan, Ding, additional, Piaggi, Pablo M., additional, Rempe, Susan L. B., additional, Ryan, Paul, additional, Salzmann, Christoph G., additional, Sayer, Thomas, additional, Saykally, Richard J., additional, Shepelenko, Margarita, additional, Sosso, Gabriele C., additional, Whale, Thomas F., additional, White, Jessica Jein, additional, Willard, Adam P., additional, and Zhang, Peng, additional

Published
2024
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60. Phase-engineering compact and flexible CsPbBr3 microcrystal films for robust X-ray detection

Author

Clinckemalie, Lotte, primary, Pradhan, Bapi, additional, Brande, Roel Vanden, additional, Zhang, Heng, additional, Vandenwijngaerden, Jonathan, additional, Saha, Rafikul Ali, additional, Romolini, Giacomo, additional, Sun, Li, additional, Vandenbroucke, Dirk, additional, Bonn, Mischa, additional, Wang, Hai I., additional, and Debroye, Elke, additional

Published
2024
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62. Electrified/charged aqueous interfaces: general discussion

Author

Advincula, Xavier R., primary, Backus, Ellen H. G., additional, Bonn, Mischa, additional, Cox, Stephen J., additional, Diebold, Ulrike, additional, Fellows, Alexander, additional, Finney, Aaron R., additional, Goel, Gaurav, additional, Hedley, Jonathan, additional, Jiang, Ying, additional, Jin, Di, additional, Kapil, Venkat, additional, Kavokine, Nikita, additional, Klein, Jacob, additional, Laage, Damien, additional, Mohandas, Nandita, additional, Morgenstern, Karina, additional, Mukherjee, Taritra, additional, Olvera de la Cruz, Monica, additional, Orlikowska-Rzeznik, Hanna, additional, Perkin, Susan, additional, Piaggi, Pablo M., additional, Rodellar, Carlos Gomez, additional, Ryan, Paul, additional, Sayer, Thomas, additional, Seyffertitz, Malina, additional, Shepelenko, Margarita, additional, Sosso, Gabriele C., additional, Thämer, Martin, additional, Vilangottunjalil, Aswathi, additional, Walker-Gibbons, Rowan, additional, Wang, Yongkang, additional, Willard, Adam P., additional, and Zhang, Peng, additional

Published
2024
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63. Dynamics and nano-rheology of interfacial water: general discussion

Author

Advincula, Xavier R., primary, Blow, Katarina E., additional, Bonn, Mischa, additional, Bui, Anna T., additional, Cheng, Yafang, additional, Cox, Stephen J., additional, Della Pia, Flaviano, additional, Diebold, Ulrike, additional, Fumagalli, Laura, additional, Goel, Gaurav, additional, Hayton, John A., additional, Jiang, Ying, additional, Kapil, Venkat, additional, Kavokine, Nikita, additional, Koga, Kenichiro, additional, Laage, Damien, additional, Lahav, Meir, additional, Miao, Shurui, additional, Michaelides, Angelos, additional, Montero de Hijes, Pablo, additional, Morgenstern, Karina, additional, Mukherjee, Taritra, additional, O'Neill, Niamh, additional, Pan, Ding, additional, Piaggi, Pablo M., additional, Rempe, Susan L. B., additional, Salvalaglio, Matteo, additional, Salzmann, Christoph G., additional, Sayer, Thomas, additional, Shepelenko, Margarita, additional, Sosso, Gabriele C., additional, Wang, Shaoheng, additional, Webber, Beau, additional, Willard, Adam P., additional, and Yao, Yang, additional

Published
2024
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64. Soft matter–water interface: general discussion

Author

Backus, Ellen H. G., primary, Ben Ari, Gil, additional, Benaglia, Simone, additional, Bonn, Mischa, additional, Bui, Anna T., additional, Cox, Stephen J., additional, Della Pia, Flaviano, additional, Fraxedas, Jordi, additional, Goel, Gaurav, additional, Jiang, Ying, additional, Jin, Di, additional, Koga, Kenichiro, additional, Laage, Damien, additional, Miao, Shurui, additional, Michaelides, Angelos, additional, Morgenstern, Karina, additional, Mukherjee, Taritra, additional, Nagata, Yuki, additional, Naito, Hidefumi, additional, Nir, Oded, additional, Olvera de la Cruz, Monica, additional, Orlikowska-Rzeznik, Hanna, additional, Pan, Ding, additional, Rempe, Susan L. B., additional, Salzmann, Christoph G., additional, Taira, Aoi, additional, Vilangottunjalil, Aswathi, additional, Wang, Shaoheng, additional, Willard, Adam P., additional, Yao, Yang, additional, and Yu, Junting, additional

Published
2024
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66. Extracting the sample response function from experimental two-dimensional terahertz-infrared-visible spectra.

Author

Seliya, Pankaj, Bonn, Mischa, and Grechko, Maksim

Subjects
*VIBRATIONAL spectra, *MOLECULAR probes, *LASER pulses, *TERAHERTZ spectroscopy, *METHYL groups, *DIMETHYL sulfoxide
Abstract

Terahertz molecular motions are often probed by high-frequency molecular oscillators in different types of non-linear vibrational spectroscopy. Recently developed two-dimensional terahertz-infrared-visible spectroscopy allows direct measuring of this coupling and, thus, obtaining site-specific terahertz vibrational spectrum. However, these data are affected by the intensity and phase of the employed laser pulses. In this work, we develop a method of extracting sample response—representing solely physical properties of a material—from experimental spectra. Using dimethyl sulfoxide as a model molecule to verify this method, we measure the coupling between C–H stretch vibration of its methyl groups and terahertz intramolecular twist and wagging modes. [ABSTRACT FROM AUTHOR]

Published
2023
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67. Water at charged interfaces

Author

Gonella, Grazia, Backus, Ellen H. G., Nagata, Yuki, Bonthuis, Douwe J., Loche, Philip, Schlaich, Alexander, Netz, Roland R., Kühnle, Angelika, McCrum, Ian T., Koper, Marc T. M., Wolf, Martin, Winter, Bernd, Meijer, Gerard, Campen, R. Kramer, and Bonn, Mischa

Published
2021
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68. Water orientation and hydrogen-bond structure at the fluorite/water interface

Author

Khatib, Rémi, Backus, Ellen H. G., Bonn, Mischa, Perez-Haro, María-José, Gaigeot, Marie-Pierre, and Sulpizi1, Marialore

Subjects
Physics - Chemical Physics
Abstract

Water in contact with mineral interfaces is important for a variety of different processes. Here, we present a combined theoretical-experimental study which provides a quantitative, molecular-level understanding of the ubiquitous and important flourite-water interface. Our results show that, at low pH, the surface is positively charged, causing a substantial degree of water ordering. The surface charge originates primarily from the dissolution of fluoride ions, rather than from adsorption of protons to the surface. At high pH we observe the presence of Ca-OH species pointing into the water. These OH groups interact remarkably weakly with the surrounding water, and are responsible for the free OH signature in the SFG spectrum, which can be explained from local electronic structure effects. The quantification of the surface termination, near-surface ion distribution and water arrangement is enabled by a combination of advanced phase-resolved Vibrational Sum Frequency Generation spectra of flourite-water interfaces and state-of-the-art ab initio molecular dynamics simulations which include electronic structure effects.

Published
2016
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69. Probing the Charge Separation Process on In2S3/Pt-TiO2 Nanocomposites for Boosted Visible-light Photocatalytic Hydrogen Production

Author

Wang, Fenglong, Jin, Zuanming, Jiang, Yijiao, Backus, Ellen H. G., Bonn, Mischa, Lou, Shi Nee, Turchinovich, Dmitry, and Amala, Rose

Subjects
Physics - Chemical Physics
Abstract

A simple refluxing wet-chemical approach is employed for fabricating In2S3/Pt-TiO2 heterogeneous catalysts for hydrogen generation under visible light irradiation. When the mass ratio between Pt-TiO2 and cubic-phased In2S3 (denoted as In2S3/Pt-TiO2) is two, the composite catalyst shows the highest hydrogen production, which exhibits an 82-fold enhancement over in-situ deposited Pt-In2S3. UV-vis diffuse reflectance and valence band X-ray photoelectron spectra elucidate that the conduction band of In2S3 is 0.3 eV more negative compared to that of TiO2, favoring charge separation in the nanocomposites. Photoelectrochemical transient photo-current measurements and optical pump - terahertz probe spectroscopic studies further corroborate the charge separation in In2S3/Pt-TiO2. The migration of photo-induced electrons from the In2S3 conduction band to the TiO2 conduction band and subsequently into the Pt nanoparticles is found to occur within 5 picoseconds. Based on the experimental evidence, a charge separation process is proposed which accounts for the enhanced activity exhibited by the In2S3/Pt-TiO2 composite catalysts.

Published
2016
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70. Surface Tension of Ab Initio Liquid Water at the Water-Air Interface

Author

Nagata, Yuki, Ohto, Tatsuhiko, Bonn, Mischa, and Kühne, Thomas D

Subjects
Physics - Chemical Physics
Abstract

We report calculations of the surface tension of the water-air interface using ab initio molecular dynamics (AIMD) simulations. We investigate the simulation cell size dependence of the surface tension of water from force field molecular dynamics (MD) simulations, which show that the calculated surface tension increases with increasing simulation cell size, thereby illustrating that a correction for finite size effects is required for the small system used in the AIMD simulation. The AIMD simulations reveal that the double-{\xi} basis set overestimates the experimentally measured surface tension due to the Pulay stress, while the triple and quadruple-{\xi} basis sets give similar results. We further demonstrate that the van der Waals corrections critically affect the surface tension. AIMD simulations without the van der Waals correction substantially underestimate the surface tension, while van der Waals correction with the Grimme's D2 technique results in the value for the surface tension that is too high. The Grimme's D3 van der Waals correction provides a surface tension close to the experimental value. Whereas the specific choices for the van der Waals correction and basis sets critically affect the calculated surface tension, the surface tension is remarkably insensitive to the details of the exchange and correlation functionals, which highlights the impact of long-range interactions on the surface tension. These simulated values provide important benchmarks, both for improving van der Waals corrections, and AIMD simulations of aqueous interfaces., Comment: 21 pages, 2 figures

Published
2016
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71. Decoupling the effects of defects on efficiency and stability through phosphonates in stable halide perovskite solar cells

Author

Xie, Haibing, Wang, Zaiwei, Chen, Zehua, Pereyra, Carlos, Pols, Mike, Gałkowski, Krzysztof, Anaya, Miguel, Fu, Shuai, Jia, Xiaoyu, Tang, Pengyi, Kubicki, Dominik Józef, Agarwalla, Anand, Kim, Hui-Seon, Prochowicz, Daniel, Borrisé, Xavier, Bonn, Mischa, Bao, Chunxiong, Sun, Xiaoxiao, Zakeeruddin, Shaik Mohammed, Emsley, Lyndon, Arbiol, Jordi, Gao, Feng, Fu, Fan, Wang, Hai I., Tielrooij, Klaas-Jan, Stranks, Samuel D., Tao, Shuxia, Grätzel, Michael, Hagfeldt, Anders, and Lira-Cantu, Monica

Published
2021
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72. Experimental and theoretical evidence for bilayer-by-bilayer surface melting of crystalline ice

Author

Sánchez, M Alejandra, Kling, Tanja, Ishiyama, Tatsuya, van Zadel, Marc-Jan, Bisson, Patrick J, Mezger, Markus, Jochum, Mara N, Cyran, Jenée D, Smit, Wilbert J, Bakker, Huib J, Shultz, Mary Jane, Morita, Akihiro, Donadio, Davide, Nagata, Yuki, Bonn, Mischa, and Backus, Ellen HG

Subjects
Physical Sciences, Chemical Sciences, Physical Chemistry, Theoretical and Computational Chemistry, crystalline ice, surface melting, sum frequency generation, stepwise, water
Abstract

On the surface of water ice, a quasi-liquid layer (QLL) has been extensively reported at temperatures below its bulk melting point at 273 K. Approaching the bulk melting temperature from below, the thickness of the QLL is known to increase. To elucidate the precise temperature variation of the QLL, and its nature, we investigate the surface melting of hexagonal ice by combining noncontact, surface-specific vibrational sum frequency generation (SFG) spectroscopy and spectra calculated from molecular dynamics simulations. Using SFG, we probe the outermost water layers of distinct single crystalline ice faces at different temperatures. For the basal face, a stepwise, sudden weakening of the hydrogen-bonded structure of the outermost water layers occurs at 257 K. The spectral calculations from the molecular dynamics simulations reproduce the experimental findings; this allows us to interpret our experimental findings in terms of a stepwise change from one to two molten bilayers at the transition temperature.

Published
2017

73. On the Fresnel factor correction of sum-frequency generation spectra of interfacial water.

Author

Yu, Xiaoqing, Chiang, Kuo-Yang, Yu, Chun-Chieh, Bonn, Mischa, and Nagata, Yuki

Subjects
DIELECTRIC function, CHEMICAL processes, ATMOSPHERIC chemistry, INDUCTIVE effect, ELECTROMAGNETIC fields
Abstract

Insights into the microscopic structure of aqueous interfaces are essential for understanding the chemical and physical processes on the water surface, including chemical synthesis, atmospheric chemistry, and events in biomolecular systems. These aqueous interfaces have been probed by heterodyne-detected sum-frequency generation (HD-SFG) spectroscopy. To obtain the molecular response from the measured HD-SFG spectra, one needs to correct the measured ssp spectra for local electromagnetic field effects at the interface due to a spatially varying dielectric function. This so-called Fresnel factor correction can change the inferred response substantially, and different ways of performing this correction lead to different conclusions about the interfacial water response. Here, we compare the simulated and experimental spectra at the air/water interface. We use three previously developed models to compare the experiment with theory: an advanced approach taking into account the detailed inhomogeneous interfacial dielectric profile and the Lorentz and slab models to approximate the interfacial dielectric function. Using the advanced model, we obtain an excellent quantitative agreement between theory and experiment, in both spectral shape and amplitude. Remarkably, we find that for the Fresnel factor correction of the ssp spectra, the Lorentz model for the interfacial dielectric function is equally accurate in the hydrogen (H)-bonded region of the response, while the slab model underestimates this response significantly. The Lorentz model, thus, provides a straightforward method to obtain the molecular response from the measured spectra of aqueous interfaces in the H-bonded region. [ABSTRACT FROM AUTHOR]

Published
2023
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74. Competing Ultrafast Energy Relaxation Pathways in Photoexcited Graphene

Author

Jensen, Soeren A., Mics, Zoltan, Ivanov, Ivan, Varol, H. Samet, Turchinovich, Dmitry, Koppens, Frank. H. L., Bonn, Mischa, and Tielrooij, Klaas-Jan

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science
Abstract

For most optoelectronic applications of graphene a thorough understanding of the processes that govern energy relaxation of photoexcited carriers is essential. The ultrafast energy relaxation in graphene occurs through two competing pathways: carrier-carrier scattering -- creating an elevated carrier temperature -- and optical phonon emission. At present, it is not clear what determines the dominating relaxation pathway. Here we reach a unifying picture of the ultrafast energy relaxation by investigating the terahertz photoconductivity, while varying the Fermi energy, photon energy, and fluence over a wide range. We find that sufficiently low fluence ($\lesssim$ 4 $\mu$J/cm$^2$) in conjunction with sufficiently high Fermi energy ($\gtrsim$ 0.1 eV) gives rise to energy relaxation that is dominated by carrier-carrier scattering, which leads to efficient carrier heating. Upon increasing the fluence or decreasing the Fermi energy, the carrier heating efficiency decreases, presumably due to energy relaxation that becomes increasingly dominated by phonon emission. Carrier heating through carrier-carrier scattering accounts for the negative photoconductivity for doped graphene observed at terahertz frequencies. We present a simple model that reproduces the data for a wide range of Fermi levels and excitation energies, and allows us to qualitatively assess how the branching ratio between the two distinct relaxation pathways depends on excitation fluence and Fermi energy., Comment: Nano Letters 2014

Published
2014
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76. A Cu3BHT‐Graphene van der Waals Heterostructure with Strong Interlayer Coupling for Highly Efficient Photoinduced Charge Separation.

Author

Wang, Zhiyong, Fu, Shuai, Zhang, Wenjie, Liang, Baokun, Liu, Tsai‐Jung, Hambsch, Mike, Pöhls, Jonas F., Wu, Yufeng, Zhang, Jianjun, Lan, Tianshu, Li, Xiaodong, Qi, Haoyuan, Polozij, Miroslav, Mannsfeld, Stefan C. B., Kaiser, Ute, Bonn, Mischa, Weitz, R. Thomas, Heine, Thomas, Parkin, Stuart S. P., and Wang, Hai I.

Published
2024
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79. Two-Dimensional Terahertz-Infrared-Visible Spectroscopy Elucidates Coupling Between Low- and High-Frequency Modes

Author

Vietze, Laura, Bonn, Mischa, Grechko, Maksim, Lotsch, H.K.V, Founding Editor, Rhodes, William T., Editor-in-Chief, Adibi, Ali, Series Editor, Asakura, Toshimitsu, Series Editor, Hänsch, Theodor W., Series Editor, Krausz, Ferenc, Series Editor, Masters, Barry R., Series Editor, Venghaus, Herbert, Series Editor, Weber, Horst, Series Editor, Weinfurter, Harald, Series Editor, Midorikawa, Katsumi, Series Editor, and Cho, Minhaeng, editor

Published
2019
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81. Cove-Edged Chiral Graphene Nanoribbons with Chirality-Dependent Bandgap and Carrier Mobility

Author

Liu, Kun, primary, Zheng, Wenhao, additional, Osella, Silvio, additional, Qiu, Zhen-Lin, additional, Böckmann, Steffen, additional, Niu, Wenhui, additional, Meingast, Laura, additional, Komber, Hartmut, additional, Obermann, Sebastian, additional, Gillen, Roland, additional, Bonn, Mischa, additional, Hansen, Michael Ryan, additional, Maultzsch, Janina, additional, Wang, Hai I., additional, Ma, Ji, additional, and Feng, Xinliang, additional

Published
2023
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82. Tunable Crystallinity and Electron Conduction in Wavy 2D Conjugated Metal–Organic Frameworks via Halogen Substitution

Author

Jastrzembski, Kamil, primary, Zhang, Yingying, additional, Lu, Yang, additional, Sporrer, Lukas, additional, Pohl, Darius, additional, Rellinghaus, Bernd, additional, Waentig, Albrecht L., additional, Zhang, Haojie, additional, Mücke, David, additional, Fu, Shuai, additional, Polozij, Miroslav, additional, Li, Xue, additional, Zhang, Jianjun, additional, Wang, Mingchao, additional, Morag, Ahiud, additional, Yu, Minghao, additional, Mateo‐Alonso, Aurelio, additional, Wang, Hai I., additional, Bonn, Mischa, additional, Kaiser, Ute, additional, Heine, Thomas, additional, Dong, Renhao, additional, and Feng, Xinliang, additional

Published
2023
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86. Structural adaptability and surface activity of tardigrade-inspired peptides

Author

Giubertoni, Giulia, primary, Chagri, Sarah, additional, Argudo, Pablo G., additional, Caporaletti, Federico, additional, Greco, Alessandro, additional, Pradel, Leon, additional, Pavan, Alberto, additional, Ilie, Ioana M, additional, Ren, Yong, additional, Ng, David, additional, Bonn, Mischa, additional, Weil, Tanja, additional, and Woutersen, Sander, additional

Published
2023
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87. Heck Migratory Insertion Catalyzed by a Single Pt Atom Site

Author

Li, Bo, primary, Ju, Cheng-Wei, additional, Wang, Wenlong, additional, Gu, Yanwei, additional, Chen, Shuai, additional, Luo, Yongrui, additional, Zhang, Haozhe, additional, Yang, Juan, additional, Liang, Hai-wei, additional, Bonn, Mischa, additional, Müllen, Klaus, additional, Goddard, William A., additional, and Zhou, Yazhou, additional

Published
2023
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93. Detection of deep-subwavelength dielectric layers at terahertz frequencies using semiconductor plasmonic resonators

Author

Berrier, Audrey, Albella, Pablo, Poyli, M. Ameen, Ulbricht, Ronald, Bonn, Mischa, Aizpurua, Javier, and Rivas, Jaime Gómez

Subjects
Condensed Matter - Materials Science, Physics - Optics
Abstract

Plasmonic bowtie antennas made of doped silicon can operate as plasmonic resonators at terahertz (THz) frequencies and provide large field enhancement close to their gap. We demonstrate both experimentally and theoretically that the field confinement close to the surface of the antenna enables the detection of ultrathin (100 nm) inorganic films, about 3750 times thinner than the free space wavelength. Based on model calculations, we conclude that the detection sensitivity and its variation with the thickness of the deposited layer are related to both the decay of the local THz field profile around the antenna and the local field enhancement in the gap of the bowtie antenna. This large field enhancement has the potential to improve the detection limits of plasmon-based biological and chemical sensors.

Published
2012
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96. Chiral Nanographene‐Based Near‐Infrared Fluorophore with Self‐Blinking Properties.

Author

Xu, Xiushang, Yang, Qiqi, Zhao, Hao, Vasylevskyi, Serhii, Bonn, Mischa, Liu, Xiaomin, and Narita, Akimitsu

Subjects
HIGH resolution imaging, PHOTON counting, FLUORESCENCE microscopy, OPTICAL properties, FLUOROPHORES, PHOTOLUMINESCENCE
Abstract

Near‐infrared (NIR) fluorophores are highly desirable for super‐resolution fluorescence microscopy; however, their optical properties are typically relatively poor, with low photo‐intensity (mean photon number below 1000), and unfavorably high on‐off blinking duty cycle. In this work, the synthesis and characterization of tetrabenzodinaphthopyranthren (TBDNP) derivative as a novel nanographene that exhibits NIR emission in the range of 800–1000 nm with a photoluminescence quantum yield of 14% are reported. TBDNP demonstrated excellent self‐blinking properties, in particular, mean photon number of >3000 and a low on–off‐duty cycle (≈10−4), which are superior to reported NIR dyes, and can be successfully employed for the NIR super‐resolution imaging. Moreover, TBDNP serves also as a chiral fluorophore, showing notable chiroptical activities from 300 to 850 nm with a high dissymmetry factor (gabs) of 0.032 at 574 nm. [ABSTRACT FROM AUTHOR]

Published
2024
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97. Intrinsic Burst-Blinking Nanographenes for Super-Resolution Bioimaging.

Author

Zhu, Xingfu, Chen, Qiang, Zhao, Hao, Yang, Qiqi, Goudappagouda, Gelléri, Márton, Ritz, Sandra, Ng, David, Koynov, Kaloian, Parekh, Sapun H., Chetty, Venkatesh Kumar, Thakur, Basant Kumar, Cremer, Christoph, Landfester, Katharina, Müllen, Klaus, Terenzio, Marco, Bonn, Mischa, Narita, Akimitsu, and Liu, Xiaomin

Published
2024
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98. Ultrafast Surface‐Specific Spectroscopy of Water at a Photoexcited TiO2 Model Water‐Splitting Photocatalyst.

Author

Backus, Ellen H. G., Hosseinpour, Saman, Ramanan, Charusheela, Sun, Shumei, Schlegel, Simon J., Zelenka, Moritz, Jia, Xiaoyu, Gebhard, Maximilian, Devi, Anjana, Wang, Hai I., and Bonn, Mischa

Subjects
PHOTON upconversion, SPECTROMETRY, INTERFACIAL reactions, IRRADIATION, WATER temperature, TIME-resolved spectroscopy
Abstract

A critical step in photocatalytic water dissociation is the hole‐mediated oxidation reaction. Molecular‐level insights into the mechanism of this complex reaction under realistic conditions with high temporal resolution are highly desirable. Here, we use femtosecond time‐resolved, surface‐specific vibrational sum frequency generation spectroscopy to study the photo‐induced reaction directly at the interface of the photocatalyst TiO2 in contact with liquid water at room temperature. Thanks to the inherent surface specificity of the spectroscopic method, we can follow the reaction of solely the interfacial water molecules directly at the interface at timescales on which the reaction takes place. Following the generation of holes at the surface immediately after photoexcitation of the catalyst with UV light, water dissociation occurs on a sub‐20 ps timescale. The reaction mechanism is similar at pH 3 and 11. In both cases, we observe the conversion of H2O into Ti−OH groups and the deprotonation of pre‐existing Ti−OH groups. This study provides unique experimental insights into the early steps of the photo‐induced dissociation processes at the photocatalyst‐water interface, relevant to the design of improved photocatalysts. [ABSTRACT FROM AUTHOR]

Published
2024
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99. Ultraschnelle oberflächenspezifische Spektroskopie von Wasser an einem photoangeregten TiO2‐Modell‐Photokatalysator zur Wasserspaltung.

Author

Backus, Ellen H. G., Hosseinpour, Saman, Ramanan, Charusheela, Sun, Shumei, Schlegel, Simon J., Zelenka, Moritz, Jia, Xiaoyu, Gebhard, Maximilian, Devi, Anjana, Wang, Hai I., and Bonn, Mischa

Subjects
TITANIUM dioxide
Abstract

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2024
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100. Aqueous chemimemristor based on proton-permeable graphene membranes.

Author

Yongkang Wang, Takakazu Seki, Gkoupidenis, Paschalis, Yunfei Chen, Yuki Nagata, and Bonn, Mischa

Subjects
GRAPHENE, ACID-base equilibrium, BRAIN-computer interfaces, ELECTRON mobility, SURFACE charges
Abstract

Memristive devices, electrical elements whose resistance depends on the history of applied electrical signals, are leading candidates for future data storage and neuromorphic computing. Memristive devices typically rely on solid-state technology, while aqueous memristive devices are crucial for biology-related applications such as next-generation brain-machine interfaces. Here, we report a simple graphene-based aqueous memristive device with long-term and tunable memory regulated by reversible voltage-induced interfacial acid-base equilibria enabled by selective proton permeation through the graphene. Surface-specific vibrational spectroscopy verifies that the memory of the graphene resistivity arises from the hysteretic proton permeation through the graphene, apparent from the reorganization of interfacial water at the graphene/water interface. The proton permeation alters the surface charge density on the CaF2 substrate of the graphene, affecting graphene’s electron mobility, and giving rise to synapse-like resistivity dynamics. The results pave the way for developing experimentally straightforward and conceptually simple aqueous electrolyte-based neuromorphic iontronics using two-dimensional (2D) materials. [ABSTRACT FROM AUTHOR]

Published
2024
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