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Subject: Crystals × WGL Institute: INP ×

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    The Role of Connectivity on Electronic Properties of Lead Iodide Perovskite-Derived Compounds
    (Washington, DC : American Chemical Society, 2017) Kamminga, Machteld E.; de Wijs, Gilles A.; Havenith, Remco W. A.; Blake, Graeme R.; Palstra, Thomas T.M.
    We use a layered solution crystal growth method to synthesize high-quality single crystals of two different benzylammonium lead iodide perovskite-like organic/inorganic hybrids. The well-known (C6H5CH2NH3)2PbI4 phase is obtained in the form of bright orange platelets, with a structure comprised of single 〈100〉-terminated sheets of corner-sharing PbI6 octahedra separated by bilayers of the organic cations. The presence of water during synthesis leads to formation of a novel minority phase that crystallizes in the form of nearly transparent, light yellow bar-shaped crystals. This phase adopts the monoclinic space group P21/n and incorporates water molecules, with structural formula (C6H5CH2NH3)4Pb5I14·2H2O. The crystal structure consists of ribbons of edge-sharing PbI6 octahedra separated by the organic cations. Density functional theory calculations including spin-orbit coupling show that these edge-sharing PbI6 octahedra cause the band gap to increase with respect to corner-sharing PbI6 octahedra in (C6H5CH2NH3)2PbI4. To gain systematic insight, we model the effect of the connectivity of PbI6 octahedra on the band gap in idealized lead iodide perovskite-derived compounds. We find that increasing the connectivity from corner-, via edge-, to face-sharing causes a significant increase in the band gap. This provides a new mechanism to tailor the optical properties in organic/inorganic hybrid compounds.
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    Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems
    (Cambridge : RSC Publ., 2015) Ferrari, Andrea C.; Bonaccorso, Francesco; Fal'ko, Vladimir; Novoselov, Konstantin S.; Roche, Stephan; Bøggild, Peter; Borini, Stefano; Koppens, Frank H. L.; Palermo, Vincenzo; Pugno, Nicola; Garrido, José A.; Sordan, Roman; Bianco, Alberto; Ballerini, Laura; Prato, Maurizio; Lidorikis, Elefterios; Kivioja, Jani; Marinelli, Claudio; Ryhänen, Tapani; Morpurgo, Alberto; Coleman, Jonathan N.; Nicolosi, Valeria; Colombo, Luigi; Fert, Albert; Garcia-Hernandez, Mar; Bachtold, Adrian; Schneider, Grégory F.; Guinea, Francisco; Dekker, Cees; Barbone, Matteo; Sun, Zhipei; Galiotis, Costas; Grigorenko, Alexander N.; Konstantatos, Gerasimos; Kis, Andras; Katsnelson, Mikhail; Vandersypen, Lieven; Loiseau, Annick; Morandi, Vittorio; Neumaier, Daniel; Treossi, Emanuele; Pellegrini, Vittorio; Polini, Marco; Tredicucci, Alessandro; Williams, Gareth M.; Hee Hong, Byung; Ahn, Jong-Hyun; Min Kim, Jong; Zirath, Herbert; van Wees, Bart J.; van der Zant, Herre; Occhipinti, Luigi; Di Matteo, Andrea; Kinloch, Ian A.; Seyller, Thomas; Quesnel, Etienne; Feng, Xinliang; Teo, Ken; Rupesinghe, Nalin; Hakonen, Pertti; Neil, Simon R. T.; Tannock, Quentin; Löfwander, Tomas; Kinaret, Jari
    We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.