Institut für Physikalische und Theoretische Chemie

Publications of the SPECSY group


  1. T. Hannappel, S. Shekarabi, W. Jaegermann, E. Runge, J.P. Hofmann, R. van de Krol, M.M. May, A. Paszuk, F. Hess, A. Bergmann, A. Bund, C. Cierpka, C. Dreßler, F. Dionigi, D. Friedrich, M. Favaro, S. Krischok, M. Kurniawan, K. Lüdge, Y. Lei, B.R. Cuenya, P. Schaaf, R. Schmidt-Grund, W.G. Schmidt, P. Strasser, E. Unger, M.V. Montoya, D. Wang, and H. Zhang. Integration of multi-junction absorbers and catalysts for efficient solar-driven artificial leaf structures: a physical and materials science perspective, Solar RRL, in print (2024), p. 2301047. DOI:10.1002/solr.202301047. Open access.
  2. J. Leist, J. Kim, H. Euchner, and M.M. May. The relevance of structural variability in the time-domain for computational reflection anisotropy spectroscopy at solid-liquid interfaces, Journal of Physics: Condensed Matter, 36 (2024), p. 185002. DOI:10.1088/1361-648X/ad215b. Open access. arXiv preprint. Data set.


  1. M. Guidat, F. Rahide, M. Löw J. Kim, H. Ehrenberg, S. Dsoke, and M.M. May. In Situ Monitoring of the Al(110)-[EMImCl]:AlCl3 Interface by Reflection Anisotropy Spectroscopy, Batteries & Supercaps 7 (2024), p. e202300394. DOI:10.1002/batt.202300394. Open access. Data set.
  2. E.A. Schmitt, M. Guidat, M. Nusshör, A.-L. Renz, K. Möller, M. Flieg, D. Lörch, M. Kölbach, and M.M. May. Photoelectrochemical Schlenk cell functionalization of multi-junction water-splitting photoelectrodes, Cell Reports Physical Science 4 (2023), p. 101606. DOI:10.1016/j.xcrp.2023.101606. Open access. Data set.
  3. M. Guidat, M. Löw, M. Kölbach, J. Kim, and M.M. May. Experimental and Computational Aspects of Electrochemical Reflection Anisotropy Spectroscopy: A Review, ChemElectroChem 10 (2023), p. e202300027. DOI:10.1002/celc.202300027. Open Access. Data set. Data set.
  4. A. Hajduk, M.A. Zare Pour, A. Paszuk, M. Guidat, M. Löw, F. Ullmann, D.C. Moritz, J.P. Hofmann, S. Krischok, E. Runge, W.G. Schmidt, W. Jaegermann, M.M. May, and T. Hannappel. (Photo-)electrochemical Reactions on semiconductor surfaces, part B: III-V surfaces–atomic and electronic structure, In: Encyclopedia of Solid-Liquid Interfaces (First Edition). Ed. by K. Wandelt and G. Busetti. Elsevier, 2023, pp. 120-156. isbn: 978-0-323-85670-6. DOI:10.1016/b978-0-323-85669-0.00113-6.


  1. M. M. May and W. Jaegermann. Combining experimental and computational methods to unravel the dynamical structure of photoelectrosynthetic interfaces, Current Opinion in Electrochemistry, 34 (2022), p. 100968. DOI:10.1016/j.coelec.2022.100968. Preprint.
  2. M. M. May and K. Rehfeld. Negative Emissions as the New Frontier of Photoelectrochemical CO2 Reduction, Advanced Energy Materials, 12 (2022), p. 2103801. DOI:10.1002/aenm.202103801. Open access.
  3. M. Kölbach, O. Höhn, K. Rehfeld, M. Finkbeiner, J. Barry, and M. M. May. The Annual-Hydrogen-Yield-Climatic-Response Ratio: Evaluating the Real-Life Performance of Integrated Solar Water Splitting Devices, Sustainable Energy & Fuels, 6 (2022), p. 4062. DOI:10.1039/D2SE00561A. Preprint. Data set.
  4. M. Schleuning, I. Y. Ahmet, R. van de Krol, and M. M. May. The role of selective contacts and built-in field for charge separation and transport in photoelectrochemical devices, Sustainable Energy & Fuels, 6 (2022), p. 3701. DOI:10.1039/D2SE00562J. Open access.
  5. J. Kim and M. M. May. Resta-like preconditioning for self-consistent field iterations in the linearized augmented planewave method, Electronic Structure 4 047003. DOI:10.1088/2516-1075/aca24a. Open access.
  6. M. Löw, M. Guidat, J. Kim, and M. M. May. The Interfacial Structure of InP(100) in Contact with HCl and H2SO4 studied by Reflection Anisotropy Spectroscopy, RSC Advances 12 (2022), p. 32756. DOI:10.1039/D2RA05159A. Open access. Data set.


  1. M. Kölbach, K. Rehfeld, and M. M. May. Efficiency Gains for Thermally Coupled Solar Hydrogen Production in Extreme Cold, Energy & Environmental Science 14 (2021), p. 4410-4417, Communication. DOI:10.1039/d1ee00650a. Open access.
  2. A. Paszuk, O. Supplie, S. Brückner,  E. Barrigón, M. M. May, M. Nandy, A. Gieß, A. Dobrich, P. Kleinschmidt, I. Rey-Stolle, and T. Hannappel. Atomic surface control of Ge(100) in MOCVD reactors coated with (Ga)As residuals, Applied Surface Science 565 (2021), p. 150513. DOI:10.1016/j.apsusc.2021.150513.
  3. M. Kölbach, C. Özen, O. Höhn, D. Lackner, M. Feifel, F. F. Abdi, M. M. May. Counterbalancing light absorption and ionic transport losses in the electrolyte for integrated solar water splitting with III-V/Si dual-junctions, Applied Physics Letters 119 (2021), p. 083904. DOI:10.1063/5.0060700. Preprint. Published version.

2020 and earlier

Peer-reviewed and book chapters:

  1. J. Geiger, M. Sprik, and M. M. May. Band Positions of Anatase (001) and (101) Surfaces in Contact with Water from Density Functional Theory, Journal of Chemical Physics 152(19) (2020) p. 194706. doi:10.1063/5.0004779. Green open access version.
  2. M. M. May, H. Stange, J. Weinrich, T. Hannappel, and O. Supplie. The impact of non-ideal surfaces on the solid-water interaction: a time-resolved adsorption study, SciPost Physics 6(5) (2019) p. 58. doi:10.21468/SciPostPhys.6.5.058. Open access.
  3. M. Mohamed, M. M. May, M. Kanis, M. Brützam, R. Uecker, R. van de Krol, C. Janowitz, and M. Mulazzi. The electronic structure and the formation of polarons in Mo-doped BiVO4 measured by angle-resolved photoemission spectroscopy, RSC Advances 9(27) (2019), pp. 15606-15614. doi:10.1039/c9ra01092k. Open access.
  4. M. M. May and K. Rehfeld. ESD Ideas: Photoelectrochemical carbon removal as negative emission technology, Earth System Dynamics 10(1) (2019), pp. 1-7. doi:10.5194/esd-10-1-2019. Open access.
  5. M. M. May and M. Sprik. Water adsorption on the P-rich GaP(100) surface: Optical spectroscopy from first principles, New Journal of Physics 20(3) (2018), p. 033031. doi:10.1088/1367-2630/aaaf38. Open access.
  6. W.-H. Cheng, M. H. Richter, M. M. May, J. Ohlmann, D. Lackner, F. Dimroth, T. Hannappel, H. A. Atwater, and H.-J. Lewerenz. Monolithic Photoelectrochemical Device for 19% Direct Water Splitting, ACS Energy Letters 3(8) (2018), pp. 1795–1800. doi:10.1021/acsenergylett.8b00920. Green open access version.
  7. M. M. May, H. Döscher, and J. Turner. High-efficiency water splitting systems, In: Integrated Solar Fuel Generators. Ed. by I. Sharp, H. Atwater, and H.-J. Lewerenz. The Royal Society of Chemistry, 2018. Chap. 12, pp. 454–499. isbn: 978-1-78262-555-1. doi:10.1039/9781788010313-00454. Green open access version.
  8. O. Supplie, M. M. May, S. Brückner, N. Brezhneva, T. Hannappel, and E. V. Skorb. In Situ Characterization of Interfaces Relevant for Efficient Photoinduced Reactions, Advanced Materials Interfaces 4(21) (2017), p. 1601118. doi:10.1002/admi.201601118. Green open access version.
  9. M. M. May, D. Lackner, J. Ohlmann, F. Dimroth, R. van de Krol, T. Hannappel, and K. Schwarzburg. On the Benchmarking of Multi-Junction Photoelectrochemical Fuel Generating Devices, Sustainable Energy & Fuels 1(3) (2017), pp. 492–503. doi:10.1039/C6SE00083E. Green open access version.
  10. O. Romanyuk, O. Supplie, T. Susi, M. M. May, and T. Hannappel. Ab initio density functional theory study on the atomic and electronic structure of GaP/Si(001) heterointerfaces, Physical Review B 94(15) (2016), p. 155309. doi:10.1103/PhysRevB.94.155309. Green open access version.
  11. O. Supplie, M. M. May, G. Steinbach, O. Romanyuk, F. Grosse, A. Nägelein, P. Kleinschmidt, S. Brückner, and T. Hannappel. Time-resolved in situ spectroscopy during formation of the GaP/Si(100) heterointerface, Journal of Physical Chemistry Letters 6(3) (2015), pp. 464–469. doi:10.1021/jz502526e. Green open access version.
  12. O. Supplie, M. M. May, P. Kleinschmidt, A. Nägelein, A. Paszuk, S. Brückner, and T. Hannappel. In situ controlled heteroepitaxy of single-domain GaP on As-modified Si(100). APL Materials 3(12), 126110 (2015). doi:10.1063/1.4939005.
  13. O. Supplie, M. M. May, C. Höhn, H. Stange, A. Müller, P. Kleinschmidt, S. Brückner, and T. Hannappel. Formation of GaP/Si(100) heterointerfaces in presence of inherent reactor residuals, ACS Applied Materials & Interfaces 7(18) (2015), pp. 9323–9327. doi:10.1021/acsami.5b02231. Green open access version.
  14. M. M. May, H.-J. Lewerenz, D. Lackner, F. Dimroth, and T. Hannappel. Efficient Direct Solar-to-Hydrogen Conversion by In Situ Interface Transformation of a Tandem Structure, Nature Communications 6 (2015), p. 8286. doi:10.1038/ncomms9286. Open access.
  15. O. Supplie, M. M. May, H. Stange, C. Höhn, H.-J. Lewerenz, and T. Hannappel. Materials for light-induced water splitting: In situ controlled surface preparation of GaPN epilayers grown lattice-matched on Si(100), Journal of Applied Physics 115(11), 113509 (2014), p. 113509. doi:10.1063/1.4869121.
  16. O. Supplie, S. Brückner, O. Romanyuk, H. Döscher, C. Höhn, M. M. May, P. Kleinschmidt, F. Grosse, and T. Hannappel. Atomic scale analysis of the GaP/Si(100) heterointerface by in situ reflection anisotropy spectroscopy and ab initio density functional theory, Physical Review B 90(23) (2014), p. 235301. doi:10.1103/PhysRevB.90.235301. Green open access version.
  17. P. Sippel, O. Supplie, M. M. May, R. Eichberger, and T. Hannappel. Electronic structures of GaP(100) surface reconstructions probed with two-photon photoemission spectroscopy, Physical Review B 89 (2014), p. 165312. doi:10.1103/PhysRevB.89.165312.
  18. A. Ramı́rez, P. Hillebrand, D. Stellmach, M. M. May, P. Bogdanoff, and S. Fiechter. Evaluation of MnOx , Mn2O3, and Mn3O4 Electrodeposited Films for the Oxygen Evolution Reaction of Water, Journal of Physical Chemistry C 118(26) (2014), pp. 14073–14081. doi:10.1021/jp500939d. Open access.
  19. M. M. May, H.-J. Lewerenz, and T. Hannappel. Optical in situ Study of InP(100) Surface Chemistry: Dissociative Adsorption of Water and Oxygen, Journal of Physical Chemistry C 118(33) (2014), pp. 19032–19041. doi:10.1021/jp502955m. Open access. Data set.
  20. M. M. May, O. Supplie, C. Höhn, R. van de Krol, H.-J. Lewerenz, and T. Hannappel. The interface of GaP(100) and H2O studied by photoemission and reflection anisotropy spectroscopy, New Journal of Physics 15(10) (2013), p. 103003. doi:10.1088/1367-2630/15/10/103003. Open access.
  21. T. Hannappel, M. M. May, and H.-J. Lewerenz. Epitaxial III-V Thin Film Absorbers: Preparation, Efficient InP Photocathodes and Routes to High Efficiency Tandem Structures, In: Photoelectrochemical Water Splitting: Materials, Processes and Architectures. Ed. by H.-J. Lewerenz and L. Peter. The Royal Society of Chemistry, 2013. Chap. 9, pp. 223–265. isbn:978-1-84973-647-3. doi:10.1039/9781849737739-00223.
  22. F. F. Abdi, T. J. Savenije, M. M. May, B. Dam, and R. van de Krol. The Origin of Slow Carrier Transport in BiVO4 Thin Film Photoanodes: A Time-Resolved Microwave Conductivity Study, Journal of Physical Chemistry Letters 4(16) (2013), pp. 2752–2757. doi:10.1021/jz4013257.
  23. H. Döscher, O. Supplie, M. M. May, P. Sippel, C. Heine, A. G. Muñoz, R. Eichberger, H.-J. Lewerenz, and T. Hannappel. Epitaxial III-V Films and Surfaces for Photoelectrocatalysis, ChemPhysChem 13(12) (2012), pp. 2899–2909. doi:10.1002/cphc.201200390. Green open access version.
  24. M. M. May, C. Brabetz, C. Janowitz, and R. Manzke. Charge-Density-Wave Phase of 1T-TiSe2 : The Influence of Conduction Band Population, Physical Review Letters 107(17) (2011), p. 176405. doi:10.1103/PhysRevLett.107.176405. Green open access version.
  25. M. M. May, C. Brabetz, C. Janowitz, and R. Manzke. The influence of different growth conditions on the charge density wave transition of 1T-TiSe2, Journal of Electron Spectroscopy and Related Phenomena 184(3–6) (2011), pp. 180–183. doi:10.1016/j.elspec.2011.01.001. Green open access version.

Not peer-reviewed (selection):

  1. M. M. May. "Effiziente Erzeugung regenerativer Brennstoffe über die solare Wasserspaltung". Naturwissenschaftliche Rundschau 72(1) (2019), pp. 10-15.
  2. M. M. May. "YaSoFo - Yet Another SOlar Fuels Optimizer" v1.2.11. Jan. 2021 on Zenodo. doi:10.5281/zenodo.1489157.
  3. M. M. May. "Photoelectron spectroscopy data of InP(100) surfaces in contact with water and oxygen". Oct. 2019 on Zenodo. doi:10.5281/zenodo.3482982.
  4. M.Kölbach, O. Höhn, K. Rehfeld, M. Finkbeiner, J. Barry, and M. M. May. "Data set for 'The annual-hydrogen-yield-climatic-response ratio: evaluating the real-life performance of integrated solar water splitting devices'". Sept. 2022 on Zenodo. DOI:10.5281/zenodo.7024843.

Media Coverage

  • The NETPEC consortium and our work there on turning CO2 into carbon flakes has been featured in the science TV show Nano on 3Sat, around minute 15:30.
  • Our solar hydrogen exhibit in the Futurium has been featured in a TV show on the Kinderkanal: The bit about hydrogen is around the time 16:20. (Public TV, so it can unfortunately only be viewed from a German IP address).
  • The topic of negative emissions seems to get quite some media attention these days. An interview on our recent ESD paper has gone online in Deutschlandfunk. (German)
  • Our solar water splitting publication in ACS Energy Letters was the topic of a more in-depth article in the Frankfurter Allgemeine Zeitung (German).
  • The popular, Cambridge-based science podcast The Naked Scientists picked up our solar water splitting publication in Nature Communications.
  • The Curious Mind Award of Matthias was covered by Manager Magazin and on FONA.