Professor

Office: 509 Physical Sciences Laboratory Building
Phone: (419) 372-7513
Email: castell@bgsu.edu
Personal site: Visit

Biographical Facts
Joined the faculty in 1998
Ph.D., The Johns Hopkins University (1996)
M.A., The Johns Hopkins University (1993)
B.A., Clark University (1991)

Research Interests
Since the end of 2002, a significant focus of our “basic” research program involves the investigation of supra-nanosecond and ultrafast photophysical processes in platinum(II) polyimine chromophores bearing a variety of carbon-based ligands. These strongly-coupled metal-organic systems are of fundamental interest and may serve in a variety of applications including optical power limiting, solar energy conversion, and photocatalysis. We are currently developing new synthetic methodologies for the preparation of novel platinum structures. Our interest in the design and photophysical characterization of metal-organic chromophores facilitates our fruitful collaboration with the Ziessel group (Strasbourg, France), where we continue to investigate the photophysical properties of p-conjugated metal-organic complexes. On the more “applied” side my group continues to develop novel inorganic compounds with pendant photochromic quenchers and their associated polymeric materials for nondestructive luminescence readout, potentially useful for binary optical data storage in both read-only and read-write-erase formats. In these systems, the luminescence response from the metal complex indirectly signals the photochromic state of the quencher, circumventing direct interrogation of the photochemically active species (nondestructive readout). Collaborators at the NMRC in Cork, Ireland have used our molecules in near-field spectroscopy in an effort to produce ultrahigh density binary memory systems with information bits of sub-micron size. A recent extension of our work in this area demonstrated the concept of optical data storage using luminescence lifetime modulation/readout. In 2005 we started to explore the solid-state vapochromism (color changes in response to VOCs) inherent in some of the platinum(II) MLCT complexes described above. We recently illustrated the concept of low power photon upconversion using simple photochemical concepts, highlighted as “News of the Week” in C&EN (August 8, 2005). This year we also established a new program in solar energy conversion, focusing largely on the design and synthesis of new Ru(II) inorganic chromophores for dye sensitized solar cells.           

Current Research Interests
Supramolecular Photochemistry & Photophysics of Metal-Organic Systems

Ultrafast and Supra-nanosecond Spectroscopy of Inorganic and Organometallic Compounds

Solar Energy Conversion, Photovoltaics & Photocatalysis

Vapochromic, Thermochromic, and Photochromic Responsive Materials

Lifetime-Based Sensing Applications of Luminescent Inorganic Dyes

Long-Range Photo-Initiated Electron and Energy Transfer

Multi-Photon Photochemistry, Nonlinear Excitation Processes & Low Power Photon UpconversionPhotocrystallography

Selected Publications
Low Power Upconversion Using MLCT Sensitizers. Islangulov, R.R.; Kozlov, D.V.; Castellano, F.N. Chem. Commun.2005, 3776-3778. (Issue 30 Inside Cover, Featured as Hot Article on RSC Visit Website, “News of the Week” in C&EN August 8, 2005)

Influence of a Gold(I)-Acetylide Bond on the Photophysics of Re(phen)(CO)3Cl. Pomestchenko, I.E.; Polyansky, D.; Castellano, F.N. Inorg. Chem. 2005, 44, 3412-3421.

Ultrafast Energy Migration in Platinum(II) Diimine Complexes Bearing Pyrenylacetylide Chromophores. Danilov, E.O.; Pomestchenko, I.E.; Kinayyigit, S.; Gentili, P.L.; Hissler, M.; Ziessel, R.; Castellano, F.N. J. Phys. Chem. A 2005, 109, 2465-2471.

Green Photoluminescence from Platinum(II) Complexes Bearing Silylacetylide Ligands. Hua, F.; Kinayyigit, S.; Cable, J.R.; Castellano, F.N. Inorg. Chem. 2005, 44, 471-473.

Photochemically Reversible Luminescence Lifetime Switching in Metal-Organic Systems. Kozlov, D.V.; Castellano, F.N. J. Phys. Chem. A2004, 108, 10619-10622.

Anti-Stokes Delayed Fluorescence from Metal-Organic Bichromophores. Kozlov, D.V.; Castellano, F.N. Chem. Commun. 2004, 2860-2861.

Room Temperature Phosphorescence from Ruthenium(II) Complexes Bearing Conjugated Pyrenylethynylene Subunits. Kozlov, D.V.; Tyson, D.S.; Goze, C.; Ziessel, R.; Castellano, F.N. Inorg. Chem.2004, 43, 6083-6092.