Education: B.S. Baker University, Baldwin City, KS, 1998 Ph.D. Georgia Institute of Technology, Atlanta, GA, 2005

Our research group, through the development and implementation of theoretical materials chemistry approaches, uncovers critical relationships among molecular composition, packing, and the resulting electronic, redox, and optical properties of novel materials of interest for energy conversion and storage applications and new generations of electronic and optoelectronic devices. With a particular emphasis on materials derived from π-conjugated molecules and polymers, we seek to derive an integrated understanding of how chemical structure, interactions at materials interfaces, and external stimuli drive molecular assembly over multiple length and time scales, and how the nature of these assemblies influence the subsequent electron- and energy-transfer processes that are key to material performance. We make use of a wide range of computational chemistry methods – including electronic-structure theories, atomistic molecular dynamics (MD) simulations, and coarse-grained (CG) techniques – and models derived from condensed-matter physics to span the hierarchical nature of the materials under study. Such a multiscale approach is required as the problem complexity ranges from needing to describe the nature and strength of the non-covalent forces that energetically drive molecular conformations and packing through the dynamic and often kinetically controlled assembly processes to the final materials-scale properties of experimental and device relevance. An ultimate goal of our studies is to guide and accelerate materials development by using the molecular- and nano-scale details that arise from the theoretical investigations to tailor structures in silico and transform these systems, in multidisciplinary collaboration with synthetic and materials scientists and device engineers, into engineered materials with controlled function.

Enhancing CO2 Absorption for Post-Combustion Carbon Capture via Zinc-based Biomimetic Catalysts in Industrially Relevant Amine Solutions. L.R. Widger, M. Sarma, R.A. Kelsey, C. Risko, C.A. Lippert, S.R. Parkin & K. Liu. International Journal of Greenhouse Gas Control (2019) 85, 156-165. DOI: 10.1016/j.ijggc.2019.04.002 Organic Semiconductors Derived from Dinaphtho-fused s-indacenes: How Molecular Structure and Film Morphology Influence Thin-Film Transistor Performance. A. Zeidell, L. Jennings, C. Frederickson, Q. Ai, J. Dressler, L. Zakharov, C. Risko, M.M. Haley & O.D. Jurchescu. Chemistry of Materials (2019) Article ASAP. DOI: 10.1021/acs.chemmater.9b01436 Impact of Atomistic Substitution on Thin-Film Structure and Charge Transport in a Germanyl-ethynyl Functionalized Pentacene. J.C. Sorli, Q. Ai, D.B. Granger, K. Gu, S. Parkin, K. Jarolimek, N. Telesz, J.E. Anthony, C. Risko & Y.L. Loo. Chemistry of Materials (2019) Article ASAP. DOI: 10.1021/acs.chemmater.9b00546 Triperyleno[3,3,3]propellane triimides: Achieving a New Generation of Quasi-D3h Symmetric Nanostructures in Organic Electronics. L. Lv, J. Roberts, C. Xiao, Z. Jia, W. Jiang, G. Zhang, C. Risko & L. Zhang. Chemical Science (2019) 10, 4951-4958. DOI: 10.1039/C9SC00849G A NIR Absorbing Indolizine-Porphyrin Push-Pull Dye for Dye-Sensitized Solar Cells. H. Cheema, A. Baumann, E.K. Loya, P. Brogdon, L.E. McNamara, C. Carpenter, N.I. Hammer, S. Mathew, C. Risko & J.H. Delcamp. ACS Applied Materials & Interfaces (2019) 11, 16474-16489. DOI: 10.1021/acsami.8b21414 Oxidation Pathways Involving a Sulfide-Endcapped Donor–Acceptor–Donor π-Conjugated Molecule and Antimony(V) Chloride. S. Chaudhry, S.M. Ryno, M. Zeller, D.R. McMillin, C. Risko & J. Mei. Journal of Physical Chemistry B (2019) 123, 3866-3874. DOI: 10.1021/acs.jpcb.9b01389 Deconstructing the Behavior of Donor-Acceptor Copolymers in Solution & the Melt: The Case of PTB7. S.M. Ryno & C. Risko. Physical Chemistry Chemical Physics (2019) 21, 7802-7813. DOI: 10.1039/C9CP00777F Bis(tercarbazole) Pyrene and Tetrahydropyrene Derivatives: Photophysical and Electrochemical Properties, Theoretical Modeling, and OLEDs. B.R. Kaafarani, T.H. El-Assaad, W.A. Smith, S.M. Ryno, F. Hermerschmidt, J. Lyons, D. Patra, B. Wex, E. List-Kratochvil, C. Risko, S. Barlow & S.R. Marder. Journal of Materials Chemistry C (2019) Advance Article. DOI: 10.1039/C8TC06266H Chemical Stabilities of the Lowest Triplet State in Aryl Sulfones and Aryl Phosphine Oxides Relevant to OLED Applications. H. Li, M. Hong, A. Scarpaci, X. He, C. Risko, J.S. Sears, S. Barlow, P. Winget, S.R. Marder, D. Kim & J.L. Brédas. Chemistry of Materials (2019) 3, 1507-1519. DOI: 10.1021/acs.chemmater.8b04235 Orgnanometallic Hydride-Transfer Agents as Reductants for Organic Semiconductor Molecules. S. Zhang, K. Moudgil, E. Jucov, C. Risko, T.V. Timofeeva, S.R. Marder & S. Barlow. Inorganica Chimica Acta (2019) 489, 67-77. DOI: 10.1016/j.ica.2019.02.003 Magnetic Ordering in a Vanadium-Organic Coordination Polymer using a Pyrrolo[2,3-d:5,4-d′]bis(thiazole)-based Ligand. Y.A. Getmanenko, C.S. Mullins, V.N. Nesterov, S. Lake, C. Risko & E. Johnston-Halperin. RSC Advances (2018) 8, 36223-36232. DOI: 10.1039/C8RA05697H Exploring Thermal Transitions in Anthradithiophene-based Organic Semiconductors to Reveal Structure-Packing Relationships. S. Li, S.M. Ryno & C. Risko. Journal of Materials Chemistry C (2018) 6, 10924-10934. DOI: 10.1039/C8TC03976C Donor or Acceptor? How Selection of the Rylene Imide End Cap Impacts the Polarity of π-Conjugated Molecules for Organic Electronics. A.J. Payne, N.A. Rice, S.M. McAfee, S. Li, P. Josse, C. Cabanetos, C. Risko, B.H. Lessard & G.C. Welch. ACS Applied Energy Materials (2018) 1, 4906-4916. DOI: 10.1021/acsaem.8b00929 Presence of Short Intermolecular Contacts Screens for Kinetic Stability in Packing Polymorphs. G.E. Purdum, N.G. Telesz, K. Jarolimek, S.M. Ryno, T. Gessner, N.C. Davy, A.J. Petty, II, Y. Zhen, Y. Shu, A. Facchetti , G.E. Collis, W. Hu, C. Wu, J.E. Anthony, R.T. Weitz, C. Risko & Y.L. Loo. Journal of the American Chemical Society (2018) 140, 7519-7525. DOI: 10.1021/jacs.8b01421 Bond Ellipticity Alternation: An Accurate Descriptor of the Non-linear Optical Properties of π-Conjugated Chromophores. T.O. Lopes, D.F. Scalabrini Machado, C. Risko, J.L. Brédas & H.C.B. de Oliveira. Journal of Physical Chemistry Letters (2018) 9, 1377-1383. DOI: 10.1021/acs.jpclett.8b00478 Positional Effects from σ-Bonded Platinum(II) on Intersystem Crossing Rates in Perylenediimide Complexes: Synthesis, Structures, and Photophysical Properties. J. Yarnell, I. Davydenko, P. Dorovatovskii, V. Khrustalev, T.V. Timofeeva, F. Castellano, S.R. Marder, C. Risko & S. Barlow. Journal of Physical Chemistry C (2018) 122, 13848-13862. DOI: 10.1021/acs.jpcc.8b01003 Effect of Halogenation on the Energetics of Pure and Mixed Phases in Model Organic Semiconductors Comprised of Anthradithiophene Derivatives and C60. A. Abtahi, S.M. Mazza, S.M. Ryno, E.K. Loya, R. Li, S.R. Parkin, C. Risko, J.E. Anthony & K.R. Graham. Journal of Physical Chemistry C (2018) 122, 4757-4767. DOI: 10.1021/acs.jpcc.7b11729 Delimited Polyacenes: Edge Topology as a Tool to Modulate Carbon Nanoribbon Structure, Conjugation, and Mobility. Q. Ai, K. Jarolimek, S. Mazza, J.E. Anthony & C. Risko. Chemistry of Materials (2018) 30, 947-957. DOI: 10.1021/acs.chemmater.7b04715 Bromination of the Benzothioxanthene Bloc: Toward New π-Conjugated Systems for Organic Electronic Applications. P. Josse, S. Li, S.V. Dayneko, D. Joly, A. Labrunie, S. Dabos-Seignon, M. Allain, B. Siegler, R. Demadrille, G.C. Welch, C. Risko, P. Blanchard & C. Cabanetos. Journal of Materials Chemistry C (2018) 6, 761-766. DOI: 10.1039/C7TC05245F On the Molecular Origin of Charge Separation at the Donor-Acceptor Interface. G. Sini, M. Schubert, C. Risko, S. Roland, O.P. Lee, Z. Chen, T.V. Richter, D. Dolfen, V. Coropceanu, S. Ludwigs, U. Scherf, A. Facchetti, J.M. Fréchet & D. Neher. Advanced Energy Materials (2018) 1702232 (2018). DOI: 10.1002/aenm.201702232