Department of Chemistry

Polymers, Materials, and Nanoscience

Research ImageMany challenging problems in the modern science and technology are related to preparation, properties, and utilization of novel functional materials. The polymer chemistry and the chemical microelectronics programs represent parts of the multidisciplinary effort in this field. The many-pronged approach includes: synthesis and molecular characterization of well-defined block and graft copolymers; preparation of new engineering thermoplastics and liquid crystalline materials; synthesis, modification and processing of polymers in super-critical carbon dioxide; chemical design of hybrid polymers for catalysis and photoredox activity, polymers for microelectronics applications including 193 nm and 157 nm photoresists and low-k dielectrics, and defined microstructures.

Chemical microelectronics is focused on preparation of organic and inorganic electronic materials; microscopic patterning of thin films using novel techniques, plasma, ion beam, laser beam, etc.; kinetics of etching and film formation; characterization of mechanical, electronic, and optical properties; spatially resolved chemical analysis of surfaces, interfaces, and thin films and microstructures. A broad variety of expertise includes visualization and probing of submicrometer surface structures by scanning probe microscopy, characterization of polymer dynamics by NMR techniques and light scattering, measurement of molecular conductivity, and analytical as well as computational and numerical methods in polymers.


Recent Research Highlights

DeSimone wins ACS Hach Award

Congratulations to Professor Joseph DeSimone and former lab members, Jason Rolland and Ben Maynor, are winners of the 2014 Kathryn C. Hach Award for Entrepreneurial Success from the American Chemical Society!

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The winners will be formally presented with the award during a March 2014 National Awards Ceremony at the ACS National Meeting in Dallas. The award recognizes the team's successful efforts to commercialize the PRINT® technology after it was invented in the DeSimone lab in 2004.


How Hybrid Solar Cells Work

An organic/inorganic hybrid solar cell, if engineered properly, can combine the advantages of both organic and inorganic materials. Organic materials typically have good light absorption coefficient, tunable energy levels and band gaps, and can be processed at low cost. On the other hand, inorganic materials offer high carrier mobility and good air stability. Subsequently, the concept of organic/inorganic hybrid solar cells has recently gained much ground. Studies have spanned from a variety of inorganic semiconductors to organic materials, and efficiency of the hybrid solar cell have reached above 10%. However, the mechanism of the hybrid solar cell is still unclear.

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As published in ACS Nano, the You Group has systematically investigated GaAs/polymers hybrid solar cells in a simple planar junction, aiming to fundamentally understand the function of semiconducting polymers in GaAs/polymers based heterojunction solar cells. A library of semiconducting polymers with different band gap and energy levels were evaluated in GaAs/polymers planar heterojunctions. The optimized thickness of active polymer layer was discovered to be ultrathin (~ 10 nm). Further, the open circuit voltage (Voc) of such GaAs/polymers planar heterojunctions was fixed around 0.6 V, regardless of the HOMO energy level of the polymer employed. Based on this and other evidence, it was concluded that n-type GaAs/polymer planar heterojunctions are not type II heterojunctions but Schottky barrier junctions with its corresponding anode, while the semiconducting polymer of appropriate energy levels can function as hole transport layer (HTL) and/or electron blocking layer (EBL). This discovery will help researchers to further design hybrid solar cell with increasingly high efficiency.


Representative Publications

Switchable Micropatterned Surface Topographies Mediated by Reversible Shape Memory. Sara A. Turner, Jing Zhou, Sergei S. Sheiko, and Valerie Sheares Ashby. ACS Appl. Mater. Interfaces, 2014, 6 (11), pp 8017–8021.

Particle Replication in Nonwetting Templates Nanoparticles with Tumor Selective Alkyl Silyl Ether Docetaxel Prodrug Reduces Toxicity. Kevin S. Chu, Mathew C. Finniss, Allison N. Schorzman, Jennifer L. Kuijer, J. Christopher Luft, Charles J. Bowerman, Mary E. Napier, Zishan A. Haroon, William C. Zamboni. Nano Lett., 2014, 14 (3), pp 1472–1476.

Controlling Molecular Weight of a High Efficiency Donor-Acceptor Conjugated Polymer and Understanding Its Significant Impact on Photovoltaic Properties. Wentao Li, Liqiang Yang, John R. Tumbleston, Liang Yan, Harald Ade, and Wei You. Adv. Mat., First published online, 14 MAR 2014, DOI: 10.1002/adma.201305251.

The Influence of Molecular Orientation on Organic Bulk Heterojunction Solar Cells. John R. Tumbleston, Brian A. Collins, Eliot Gann, Wei Ma and Harald Ade, Liqiang Yang, Andrew C. Stuart and Wei You. Nature Photonics (2014) doi:10.1038/nphoton.2014.55.

Copolymerization of Metal Nanoparticles: A Route to Colloidal Plasmonic Copolymers. Kun Liu, Ariella Lukach, Kouta Sugikawa, Siyon Chung, Jemma Vickery, Heloise Therien-Aubin, Bai Yang, Michael Rubinstein, and Eugenia Kumacheva. Angewandte Chemie International Edition, Volume 53, Issue 10, pages 2648–2653, March 3, 2014.

Storage of Electrical Information in Metal–Organic-Framework Memristors. Seok Min Yoon, Scott C. Warren, and Bartosz A. Grzybowski. Article first published online: 14 MAR 2014, DOI: 10.1002/anie.201309642.

Self-Healing of Unentangled Polymer Networks with Reversible Bonds. Evgeny B. Stukalin, Li-Heng Cai, N. Arun Kumar, Ludwik Leibler, and Michael Rubinstein. Macromolecules, 2013, 46 (18), pp 7525–7541.

Nonflammable Perfluoropolyether-Based Electrolytes for Lithium Batteries. Dominica H. C. Wong, Jacob L. Thelen, Yanbao Fu, Didier Devaux, Ashish A. Pandya, Vincent S. Battaglia, Nitash P. Balsara, and Joseph M. DeSimone. PNAS, Online: DOI10.1073/pnas.1314615111.

Synthetically Encoding 10 nm Morphology in Silicon Nanowires. Joseph D. Christesen, Christopher W. Pinion, Erik M. Grumstrup, John M. Papanikolas, and James F. Cahoon. Nano Lett., 2013, 13 (12), pp 6281–6286.

Nanoparticle Drug Loading as a Design Parameter to Improve Docetaxel Pharmacokinetics and Efficacy. Kevin S. Chu, Allison N. Schorzman, Mathew C. Finniss, Charles J. Bowerman, Lei Peng, James C. Luft, Andrew J. Madden, Andrew Z. Wang, William C. Zamboni, Joseph M. DeSimone. Biomaterials, Volume 34, Issue 33, November 2013, Pages 8424–8429.