Synthesis, electronic structure, and optical properties of diamond clusters - diamondoids
Final Report Abstract
Clusters and nanoparticles can be considered to constitute a new type of material, since they often have properties which are fundamentally different from those of molecules or bulk solids. Diamondoids are a class of sp3‐hybridized carbon nanoparticles that, in recent years, have become increasingly popular for study due to their perfect mass‐ and shape selectability. As such they present ideal opportunities to study the electronic properties of nanoparticles and compare theory to experiments, since electrically neutral diamondoids can be probed in the gas phase with a variety of spectroscopic techniques. Furthermore, they have many unique properties that make them attractive for industrial applications, such as high chemical stability and bio‐compatibility (medical applications, chemical markers), negative electron affinity (electron emitters), intrinsic UV luminescence and a band gap tunable by surface modification or –functionalization (semi‐conductor industry). The studies on diamondoids of various kinds, undertaken during the funding period, proved highly successful, with a number of resulting publications. The main results were that diamondoids show interesting characteristics depending on their size and symmetry and that it is possible to control their fluorescence in the UV region by changing these parameters as well as through functionalization of pristine diamondoids. These findings have led to a deeper understanding of diamondoids in particular and of very small semi‐conductor clusters in general. Due to practical problems, the synthesis side of the project did not yet produce the desired results. This, however, was mitigated by the rapid development of chemical synthesis methods for the diamondoids by the Schreiner group (University of Giessen), where a collaboration was initiated early in the funding period. Another collaboration was initiated together with the theory groups of Prof. V. Bonačić‐Koutecký and Prof. R. Mitrić in order to provide multiple synergies, and turned out very valuable for the interpretation of the experimental results. Overall, the results from the funding period have shown that diamondoids are a promising candidate for a wide variety of studies on size‐, symmetry‐ and composition effects in semi‐conductor nano‐particles, thereby providing first answers to the questions posed in the original proposal.
Publications
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"Optical Response of Diamond Nanocrystals as a Function of Particle Size, Shape, and Symmetry," Physical Review Letters, vol. 103, p. 047402, 2009
L. Landt, K. Klünder, J. E. Dahl, R. M. K. Carlson, T. Möller and C. Bostedt
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„Intrinsic photoluminescence of adamantane in the ultraviolet spectral region,“ Physical Review B, Nr. 80, p. 205323, 2009
L. Landt, W. Kielich, D. Wolter, M. Staiger, A. Ehresmann, T. Möller und C. Bostedt
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„Experimental and theoretical study of the absorption properties of thiolated diamondoids,“ Journal of Chemical Physics, Nr. 132, p. 144305, 2010
L. Landt, C. Bostedt, D. Wolter, T. Möller, J. E. Dahl, R. M. K. Carlson, B. A. Tkachenko, A. A. Fokin, P. R. Schreiner, A. Kulesza, R. Mitric und V. Bonacic‐Koutecky
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„The influence of a single thiol group on the electronic and optical properties of the smallest diamondoid adamantane,“ Journal of Chemical Physics, Nr. 132, p. 024710, 2010
L. Landt, M. Staiger, D. Wolter, K. Klünder, P. Zimmermann, T. M. Willey, T. van Buuren, D. Brehmer, P. R. Schreiner, B. A. Tkachenko, A. A. Fokin, T. Möller und C. Bostedt
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„Electronic structure tuning of diamondoids through functionalization,” Journal of Chemical Physics 138, 024310 (2013)
T. Rander, M. Staiger, R. Richter, T. Zimmermann, L. Landt, D. Wolter, J. E. Dahl, R. M. K. Carlson, B. A. Tkachenko, N. A. Fokina, P. R. Schreiner, T. Möller, C. Bostedt
