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Phil Castellano

Professor

He/Him/His

Goodnight Innovation Distinguished Chair and Professor

Department of Chemistry

Partners Building III 319

Bio

Felix (Phil) Castellano earned a B.A. in Chemistry from Clark University in 1991 and a Ph.D. in Chemistry from Johns Hopkins University under the direction of Jerry Meyer in 1996. Following an NIH Postdoctoral Fellowship at the University of Maryland, School of Medicine, working with Joe Lakowicz, he accepted a position as Assistant Professor at Bowling Green State University in 1998. He was promoted to Associate Professor in 2004, to Professor in 2006, and was appointed Director of the Center for Photochemical Sciences in 2011. In 2013, he moved his research program to North Carolina State University where he is currently the Goodnight Innovation Distinguished Chair. He was appointed as a Fellow of the Royal Society of Chemistry (FRSC) in 2015, earned the I-APS Award in Photochemistry in 2019, and was elected as an AAAS Fellow in 2020. He is also the inaugural Editor-in-Chief of Chemical Physics Reviews, a peer-reviewed journal from AIPP. His current research focuses on metal-organic chromophore photophysics and energy transfer, photochemical upconversion phenomena, thermally-activated delayed photoluminescence processes, solar fuels photocatalysis, energy transduction at semiconductor/molecular interfaces, photoredox catalysis, fuel-forming chemical reactions, ultrafast transient bond-making and bond-breaking processes, and excited state electron transfer.

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Education

Ph.D. Chemistry Johns Hopkins University 1996

B.A. Chemistry Clark University 1991

Publications

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Grants

Date: 09/01/22 - 8/31/23
Amount: $750,000.00
Funding Agencies: US Dept. of Energy (DOE)

We propose a quantum spin technology to image biochemical pathways in the rhizosphere with unprecedented chemical detail and sensitivity. Specifically, the proposed technology transfers the quantum entangled nuclear spin order of hydrogen gas, to metabolites, including nitrate, amino acids, nitrogen and pyruvate, to enable molecular imaging of their metabolic transformations without any penetration depth limitations such that molecular turnover and metabolism can be observed directly in soil.

Date: 08/15/20 - 7/31/23
Amount: $225,000.00
Funding Agencies: National Science Foundation (NSF)

In this proposed collaborative project, Professors Felix N. Castellano (NC State) and Lin X. Chen (Northwestern U) are developing the spectroscopy and chemistry necessary for the study of photoinduced energy transfer processes in covalently linked chromophore systems. These targeted molecules convert and accumulate energy from sunlight that can ultimately drive photocatalytic reactions for generating chemical fuels. Mechanistic details enabling multiple-electron conversion processes will be investigated through newly developed two-dimensional electronic spectroscopy, optical anisotropy spectroscopy, and by the design of new molecular architectures. The proposed work seeks an understanding of intrinsic electronic couplings between the multiple chromophores within inorganic/organic hybrid molecules and materials. Using ultrafast laser pulses, electron density will shift on time scales faster than the period of the ground state vibrational stretching vibrations; dipole correlations using transient optical anisotropy and electronic coupling through two-dimensional electronic spectroscopy will be systematically investigated. The implications of these coherent motions in chemical and photochemical processes including energy transfer and energy transport within and between molecules will be revealed.

Date: 05/15/14 - 5/14/23
Amount: $1,788,945.00
Funding Agencies: US Dept. of Energy (DOE)

The proposed research is composed of two parallel lines of inquiry addressing fundamental aspects of photo-induced energy transfer processes as they relate to the emerging topic of solar photon wavelength upconversion achieved through the regenerative photochemical process of sensitized triplet-triplet annihilation (TTA). The concepts developed in this proposal address topics and processes central to solar energy conversion while being cognizant of sustainable sensitizer design and compatibility of the proposed photochemical processes within aqueous environments. First, we seek to translate sensitized TTA-based upconversion into more sustainable formats using highly abundant elements in sensitizer design. Two representative molecular designs will be developed to promote intramolecular triplet state generation for use in upconversion schemes: (1) new CuI charge transfer sensitizers designed to possess markedly extended excited state lifetimes using pendant triplet acceptors to intramolecularly produce either “pure” organic triplets or equilibrated excited states based on the triplet reservoir effect; and (2) high extinction coefficient SnIV porphyrin sensitizers covalently tethered to energetically appropriate acceptors/annihilators in their axial positions, thereby circumventing the limitations imposed by bimolecular triplet sensitization. As a result, the typical sequence of two consecutive bimolecular reactions, triplet sensitization and annihilation, becomes reduced to only the latter which will then take place between two energized acceptor/annihilator molecules located on two distinct porphyrins. The second series of proposed investigations address a key criterion for potential integration into solar fuels producing schemes, namely, photochemical upconversion that decisively functions in water. In order to promote regenerative upconversion photochemistry in water: (1) we will directly address the problem by evaluating the photochemical interactions occurring between water-soluble phthalocyanine triplet sensitizer donors and acceptors/annihilators initially based on high fluorescence quantum efficiency perylenediimide (PDI) dyes, affording near-IR-tovisible light conversions; (2) micellar nanoreactors will be used to host/encapsulate various hydrophobic upconversion pairs in water, absorbing low energy light and radiating higher energy photons into the immediately adjacent aqueous solution; and (3) mesoporous silica nanoparticles will be used to examine upconversion occurring in nanoporous environments either between surface-anchored sensitizers and freely diffusing acceptors/annihilators or between chromophores loaded/adsorbed into the pores of the material. The nature of the micellar nanoreactors and mesoporous silica will permit detailed photophysical/photochemical examinations of these materials in water.

Date: 10/01/21 - 3/31/23
Amount: $84,000.00
Funding Agencies: US Dept. of Energy (DOE)

The proposed work selects transition metal complexes (TMCs) and their hybrids with inorganic nanoparticles (TMC/NP) as platforms to study effects of ultrafast coherent electronic or atomic motions in photochemical reactions to transfer energy and charges or to break or form bonds in chemical reactions. The project aims at understanding how ultrafast electronic and nuclear coherent motions in TMC and TMC/NP materials lead to selected outcomes in photochemical reactions, and how these chemical reactions can be controlled using external stimuli that couple with phases of the electronic and atomic motions. A key component of this program will be the direct detection of coherent nuclear and electronic motions correlated to light energy capture and conversion in TMC and TMC/NP systems using the femtosecond (fs) X-ray pulses from the X-ray free electron laser, Linac Coherent Light Source (LCLS). Both ultrafast laser and X-ray measurements will be used to track excited-state electronic and nuclear structural dynamics, coherent excited-states dynamics, and transitions from coherent excited to product states. Ultrafast X-ray studies at LCLS will be augmented with measurements from picosecond synchrotron X-ray slicing light sources to prototype LCLS experiments and characterize reaction outcomes using coherence phase relevant triggering schemes in TMC and TMC/NP materials. Theory will be partnered with experiments to achieve a fundamental understanding of excited-state electronic and nuclear coherences underlying photochemical reaction dynamics, and to elucidate and model spectral and dynamic features observed in the laser and X-ray experiments. The team includes experimentalists and theorists with the expertise ranging from synthesis, ultrafast laser spectroscopy, to forefront theoretical calculations to model coherent control and ultrafast photochemical reaction trajectories as well as X-ray absorption/emission spectroscopy and scattering. The cohesive approach of this project is organized by two themes: 1.) ultrafast electronic and structural coherence in TMC and TMC/NP materials relevant to solar energy conversion and catalysis, 2.) coherent control of electron/energy transfer in transition metal complex/nanoparticle interfacial energy/electron transfer processes on the ultrafast time scales.

Date: 03/01/19 - 2/28/23
Amount: $1,246,252.00
Funding Agencies: New Fusion

The general project concept investigates the utilization of triplet-triplet annihilation (TTA, also known as triplet fusion) to generate blue photoluminescence emission in next generation organic light-emitting diodes (OLEDs) that would achieve unprecedented operational lifetimes and stability. To date, we have prepared several new blue emitter molecules and electron/hole transport materials along with large numbers of blue-emitting device structures featuring operational characteristics that exclusively function through the triplet fusion phenomenon. The proposed work seeks to further this research into blue emitting materials while demonstrating full color displays operating using the same principles.


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