Thursday, February 6, 2014, 6:00 PM (The LI-ACS Seminar)
Dr. Wayne E. Jones (SUNY at Binghamton)
Inorganic/Organic Hybrid Structures for Photovoltaics: Low Cost Roll to Roll Processing of Solar Cells
The preparation of competitive solar energy conversion technologies has been limited by the cost and efficiency of modern materials. We have been developing new approaches to layered inorganic/organic photovoltaic materials on flexible substrates. The flexible thin film solar cell is based on a combination of organic bulk heterojunction strategies with semi-conductor nanostructures. These hybrid inorganic/organic systems require development of new materials and processing technologies in order to make them suitable for low cost roll-to-roll manufacturing. Titanium dioxide nanoparticles, conducting polymer films such as polyethylenedioxythiophene (PEDOT) and polyaniline (PANI), and self-assembled layered materials of laponite have been prepared on polyethylene terephthalate (PET) substrates. We have also explored alternative transparent conducting electrode layers for flexible substrates including doped ZnO and CVD deposited conducting polymers. In this presentation, we will explore recent advances in the preparation, processing, and testing of these hybrid photovoltaic devices completed at the new Center for Autonomous Solar Power (CASP) and the Center for Advanced Microelectronics Manufacturing (CAMM) at Binghamton University’s Center of Excellence./p>
Friday, February 7, 2014, 1:00 PM
Dr. Wayne E. Jones (SUNY at Binghamton)
Fluorescent Conjugated Polymer Chemosensors for the Environment Based on Inorganic-Organic Hybrid Structures
Developing chemosensory devices selective for transition metals and other pollutants represents a critical need for the environmental community. Fluorescent conjugated polymer chemosensors have several advantages over small molecule sensors due to their high sensitivity, processibility, and ease of modification. Previously, our group has synthesized a series of fluorescent polymerchemosensors with a poly[p-(phenyleneethylene)-alt-(thienyleneethynylene)](PPETE) conjugated backbone. The transition metal loading dependence of these materials provides fundamental information regarding the role of energy transfer in the fluorescent chemosensor quenching mechanism. Recently, this work has been extended by addition of a N,N,N’-trimethylethylenediamino receptor group which undergoes photoinduced electron transfer (PET) to the polymer exciton. Upon binding to analytes such as protons or some transtion metal cations, the PET process is disabled and the emission from the polymer is enhanced. This system has been found to be particularly sensitive to Hg2+ ions that cause the fluorescence of the polymer to increase by a factor of ~ 2.7. Synthesis, characterization and photophysical behavior of this polymer will be discussed as well as its application to future “Turn-on” sensor designs.
Thursday, March 6, 2014, 6:00 PM (The LI-ACS Seminar)
Dr. Yolana A. Small (York College, CUNY)
Title: Water Splitting Chemistry using Photocatalytic Semiconductors and Molecular Co-Catalysts
Abstract: From the energy demands of the modern age and the need to preserve environmental quality, there is a current push towards finding renewable energy technology. Fuel cells are one such target because the energy source can be garnered from solar power and the naturally abundant water supply. Water oxidation and hydrogen production are fundamental steps in the so-called water splitting process. The availability of photo-generated excitons in semiconductor materials facilitates water oxidation and proton reduction through an unknown mechanism. Efficient photoanodes for water oxidation are crucial for any scheme to convert the energy in sunlight to fuels. We utilize computational methods, based on density functional theory, to obtain a fundamental, atomistic understanding of water oxidation mechanisms in photocatalytic semiconductors. To aid our understanding of hydrogen production and oxidation, we turn to hydrogenase enzymes which catalyze both processes efficiently. Aiming to design hydrogenase-like catalysts with equal efficiency, computational methods are applied to explore features of molecular catalysts and evaluate their contributions to overall catalytic ability.
Friday, March 21, 2014, 1:00 PM
Prof. Peter Diaczuk (John Jay College of Criminal Justice)
Chemistry in Crime Scene Reconstruction
Crime scene reconstruction can present very difficult and complex challenges to the forensic scientist. Correctly interpreting the crime scene to reconstruct the events that took place during the act of a crime can provide both useful leads in the investigative stage and important facts for the jury to consider during the adjudicative stage. The proper interpretation of these crime scene events is not a trivial task; however, the forensic scientist must often rely on many aspects of their education as the scene is reconstructed. A critical assessment of the evidence can often be aided by the application of chemistry and established chemical reactions as a hypothesis is being developed. This presentation will highlight some of the useful chemistry that a forensic scientist might employ in a crime scene reconstruction.
Thursday, April 3, 2014, 6:00 PM (The LI-ACS Seminar)
Dr. Ron Breslow (Columbia University)
How did it all get started? Prebiotic chemistry. The Origin of Terrestrial Homochirality in Amino Acids and Nucleosides.
Work on artificial enzymes that perform the synthesis of amino acids from ketoacids led us to examine the properties of alpha-methyl amino acids. Recently these have been identified as components of carbonaceous chondritic meteorites such as the one that landed near Murchison Australia in the last century. These unusual amino acids arrive with excesses of stable chirality, all of the L configuration, and we will describe how they could have been formed. We showed that they can generate normal amino acids under credible prebiotic conditions, and with some chirality transfer. We also showed that the modest chirality that resulted could be amplified to high enantioexcesses of normal L aminoacids, using either thermodynamic or kinetic processes. We have shown that we can also amplify modest excesses of D nucleosides to high enantioexcesses by related processes. Finally, we have also shown the likely origin of D sugars. The resulting amino acids, sugars, and nucleosides can then be suitable materials for the creation of life.