News & Events

Image of the Month
Posted Date: March 1, 2015
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This image, recorded with molecular resolution at 150 °C, provides direct evidence for the stability of the metal-organic chains at high temperature on the Au(100) surface. Elevated-temperature STM image collected with the sample held at 425 K showing platinum(II) dipyridyltetrazine 1D chains on the reconstructed Au(100) surface.

The formation and stabilization of well-defined transition-metal single sites at surfaces may open new routes to achieve higher selectivity in heterogeneous catalysts. Organic ligand coordination to produce a well-defined oxidation state in weakly reducing metal sites at surfaces, desirable for selective catalysis, has not been achieved. Here, we address this using metallic platinum interacting with a dipyridyl tetrazine ligand on a single crystal gold surface. X-ray photoelectron spectroscopy measurements demonstrate the metal−ligand redox activity and are paired with molecular-resolution scanning probe microscopy to elucidate the structure of the metal−organic network. Comparison to the redox-inactive diphenyl tetrazine ligand as a control experiment illustrates that the redox activity and molecular-level ordering at the surface rely on two key elements of the metal complexes: (i) bidentate binding sites providing a suitable square-planar coordination geometry when paired around each Pt, and (ii) redox-active functional groups to enable charge transfer to a well-defined Pt(II) oxidation state. Ligand-mediated control over the oxidation state and structure of single-site metal centers that are in contact with a metal surface may enable advances in higher selectivity for next generation heterogeneous catalysts.

Credits: Daniel Skomski, Christopher D. Tempas, Kevin A. Smith, and Steven L. Tait*
Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States

Microscope: RHK Technology AFM/STM UHV 7500

Control System: RHK Technology SPM 1000 Control System

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Image of the Month
Posted Date: February 1, 2015
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Mid infrared plasmon mode observed in doped semiconductor SrTiO3 fabricated by Argon ion etching. Color represents near field optical signal, which is overlaid on top of the topography profile in a 24µm square area.

The image is obtained by a RHK broadband variable temperature scanning near field optical microscope.

Credits: Professor Cheng Cen, Department of Physics and Astronomy, West Virgina University, Morgantown, WV

Microscope: RHK broadband variable temperature scanning near field optical microscope.

Control System: RHK R9-STM and PMC100

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Press Releases
Posted Date: January 14, 2015

RHK Technology, Inc. is proud to highlight the outstanding performance of our PanScan Freedom-LT SPM at the AVS 61st International Symposium and Exhibition 2014. Troy, MI – The PanScan-Freedom LT is an innovative new closed-cycle cryogen-free system for stable low temperature performance, unprecedented low drift, exceptional spectroscopy performance, and atomic resolution in a surprisingly compact, simple, and affordable package. The extreme stability of this microscope was demonstrated in the Baltimore Convention Center exhibition hall using an Indium doped Bismuth Selenide sample, showing both a high-level of isolation from the vibration of the Closed-Cycle Cryostat as well as the environment of the hall, yielding excellent performance with the noise level below 1 pm. The goal of a helium-free STM has been an elusive dream for the many researchers unable to secure a steady supply of affordable liquid helium.

RHK Technology, Inc. manufactures ultra-high vacuum scanning probe microscopes (UHV SPM), Control Systems, and Nano-Optical instruments for research in major universities and government laboratories around the globe. RHK is based in Troy, MI, USA.

Link to Press Release

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Image of the Month
Posted Date: January 1, 2015
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These figures show the arrangement of 5 and 6-membered rings of D2O on the Pt(111) surface, imaged at 80 K.

Credits: Daniel Killelea, Rachael Farber and Jon Derouin at Loyola University,Chicago and Ludo Juurlink at Leiden University, The Netherlands

Microscope: RHK PanScan Flow-LT STM

Control System: RHK R9-STM and PMC100

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