Size and shape tunable periodic structures derived from functional block copolymers
Using controlled free-radical polymerization techniques, we are making model block copolymers of varying chemical functionalities. Characteristic of the polymerization techniques used, these block copolymers are narrow in molecular weight distributions. Depending on the details of the synthesis parameters – composition, monomer type, etc. – these block copolymers spontaneously microphase separate to form periodic nanostructures. Current research efforts in this area focus on gradient copolymers with controlled composition profiles, as well as pH- and temperature-responsive hydrogels.
Solution-processable organic conductors and semiconductors for thin-film electronics
The ability to replace thermally-evaporated metal and organic semiconductors with solution-processable counterparts as active device components will lower capital and operational costs associated with thin-film electronics fabrication. We are examining the processing-structure-property relationships of these materials to assess their viability. Current research efforts in this area focus on water-dispersible, conductive polyaniline and several p-type solution-processable anthradithiophenes. These materials, respectively, find use as electrodes and active layers in organic transistors and solar cells.
Soft lithography and soft-contact lamination for plastic electronics
The chemical- and mechanical fragility of organic semiconductors calls for the development of non-invasive patterning technologies for establishing efficient electrical contact. Our group has developed nanotransfer printing (nTP), soft-contact lamination (scL) and stamp-and-spin-cast as means to fabricate functional organic thin-film devices. Research in this area continues to explore elastomeric-stamp-based patterning schemes for creating high-resolution functional features on rigid and flexible substrates over large areas. These features are either directly transferred onto or laminated against the electrically-active components to complete the circuits of organic transistors and solar cells.
Self-assembled monolayers facilitate interfacial engineering in organic solar cells
Previously, our efforts in this area entailed the understanding the assembly of conjugated molecules on metal and semiconductor surfaces. High-resolution spectroscopic techniques, including transmission and reflectance infra-red spectroscopy and synchrotron-based near-edge X-ray absorption fine structure spectroscopy were used to elucidate the ensemble-averaged structure and orientation of the molecular assembly. Current work builds on our previous know-how; we are exploiting the molecular dipoles induced by and surface energy presented by the organization of self-assembled monolayers to engineer the electrode-photo-active later interface in organic solar cells.
Funding Sources and Supporters
Alfred P. Sloan Foundation
Arnold and Mabel Beckman Foundation
Camille and Henry Dreyfus Foundation
National Science Foundation - CAREER Award through DMR; PIRE; SOLAR Initiative
Office of Naval Research - Photovoltaics Program
Princeton Center for Complex Materials, a MRSEC funded by the NSF
Toppan Photomasks Inc. (formerly Dupont Photomasks, Inc.)
W.M. Keck Foundation
Fellowships and Scholarships
NSF Integrative Graduate Education and Research Traineeship Fellowship in Nanotechnology for Clean Energy to AMH
National Defense Science and Engineering Graduate Fellowship to SSL and AMH
NSF Graduate Fellowship to KBG, JDT, AKH
Department of Homeland Security Fellowship to TLB
UT Harrington Fellowship to TLB
Il Ju Academic Foundation Overseas Graduate Fellowship to KSL
UT College of Engineering Fellowships to KCD, KBG, TLB
UT Undergraduate Research Fellowships to SMM, MFK, AEA, JJN, RT
Intel Undergraduate Research Fellowship to SHC
REU Supplemental Grant to CAREER Award to RT, SRM
Lidow Senior Thesis Fund to KAC, KPB, JMF, RP, LS