Optical Sciences

Biomolecules and nanostructures

The Optical Sciences group studies the interaction of light and matter. Our current focus is on detection and sensing/imaging with an emphasis on the development of integrated photonics. We are part of Twente University's Department of Science and Technology and member of the MESA+ institute.


The role of bridging ligands in light-induced hydrogen generation reactivity for Ru/Pd bimetallic assemblies

  • Qing Pan - Former member
  • Annemarie Huijser - Former member
  • Divya Sharma - Former member

  • Photocatalytic hydrogen production has long been targeted as an attractive way to directly convert solar energy into chemical fuel. A simple H2 generation photocatalyst may be comprised of a light-harvesting Ru(II)-polypyridyl center and a catalytic metal (Pd(II)) center, which are connected by a bridging ligand. Based on this design, two different photocatalysts with different bridging ligands were tested (RuPt1 and RuPt2, Figure 1). RuPt1 was found to be photoactive for hydrogen evolution, whereas RuPt2 not.

    Figure 1. Structure of complexes RuPt1 (left) and RuPt2 (right).

    In this project, the underlying photophysics determining the distinct photocatalytic performance of RuPt1 and RuPt2 are explored by time resolved spectroscopic methods. Ultrafast transient absorption (TA) reveals fast (ca. 30 ps) directional electron transfer from the peripheral bpy ligands towards the bridging 2,5-tpy ligand in RuPt1. This process is likely competed by a bpy-localized cooling process taking place within ca. 10 ps. A long-lived excited state lifetime (>88 ns) was also observed by time-resolved photoluminescence. On the contrary, the inactivity of RuPt2 is explained by a fast recombination (ca. 100 ps) of the excited chromophore, possibly due to a lowered metal-centered (3MC) deactivation state caused by steric encumbrance.


    The following articles have been published regarding this project:

    Supramolecular Bimetallic Assemblies for Photocatalytic Hydrogen Generation from Water

    (abstract) (full pdf)
    Tanja Kovacs, Qing Pan, Philipp Lang, Laura O’Reilly, Sven Rau, Wesley R. Browne, Mary T. Pryce, Annemarie Huijser, and Johannes G. Vos
    Faraday Discussions
    issue 185, p143 - 170 dec. 1, 2015

    Directionality of Ultrafast Electron Transfer in a Hydrogen Evolving Ru-pd Based Photocatalyst

    (abstract) (full pdf)
    Qing Pan, Francesco Mecozzi, Jeroen P. Korterik, Divya Sharma, Jennifer L. Herek, Johannes G. Vos, Wesley R. Browne, and Annemarie Huijser
    Journal of Physical Chemistry C
    118 (36), pp 20799-20806 aug 19, 2014

    Probing the origin of fluorescence quenching of a graphene-porphyrin hybrid material

    (abstract) (full pdf)
    Divya Sharma, Xiaoyan Zhang, Ben L. Feringa, Wesley R. Browne, Jennifer L. Herek, and Annemarie Huijser
    EPJ Web of Conferences
    vol. 41 p. 04027 march 13, 2013
    Printable version