Chemistry Department Seminar

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Dr. Liming Dai of Case Western Reserve University will be presenting a seminar titled Functional Energy Materials: From 1D and 2D Polymers to 3D Carbon Nanomaterials. 

Abstract: With the rapid increase in the global energy consumption, there is a pressing need for clean and renewable energy alternatives. Polymers have been traditionally used as electrically insulating materials: after all, metal wires are coated in plastics to insulate them. Various conjugated macromolecules with alternating single and double bonds can now be synthesized with the processing advantages of plastics and the optoelectronic properties of inorganic semiconductors for optoelectronic device applications, including polymer photovoltaic cells [1]. 

Having conjugated all-carbon structures, carbon nanomaterials, including 1D carbon nanotubes (CNTs) and 2D graphene sheets, also possess certain similar optoelectronic characteristics as conjugated macromolecules, apart from their unique surface/size effects. With the rapid development in nanoscience and nanotechnology, graphitic carbon nanomaterials have been playing a more and more important role in the development of efficient energy conversion and storage devices, including solar cells, fuel cells, supercapacitors, and batteries [2-4]. Recently, considerable efforts have been made to utilize graphitic carbon nanomaterials, along with conjugated polymers, as energy materials and tremendous progress has been achieved. More recently, certain 2D conjugated polymers and 3D graphitic carbon architectures (e.g., CNT-graphene pillared networks, graphene foams) have been demonstrated to show additional advantages for efficient energy conversion and storage [5,6].
In this talk, I will summarize our work on the rational design and development of multi-dimensional conjugated polymers and graphitic carbon nanomaterials for efficient energy conversion and storage, including polymer solar cells containing graphitic carbon nanomaterials for improved charge transport, fuel cells and metal-air batteries with carbon nanomaterials/polymers as metal-free catalysts for oxygen reduction and evolution, and flexible supercapacitors based on CNT-/graphene-based electrodes for energy storage. A brief overview of this exciting field, along with some challenges and opportunities, will also be presented.
 
 
References
[1] Liu, J.; Durstock, M.; Dai L. Energy & Environ. Sci. 2014, 7, 1297.
[2] Gong, K.; Du, F.; Xia, Z.; Dustock, M.; Dai, L. Science 2009, 323, 760.
[3] Yu, D.; Goh, K.; Wang, H.; Wei, L.; Jiang, W.; Zhang, Q.; Dai, L.; Chen, Y. et al., Nature Nanotechnol. 2014, 9, 555.
[4] Shui, J.; Wang, M.; Du, F.; Dai, L. Sci. Adv. 2015, 1: e 100129.
[5] Dai, L. Acc. Chem. Res. 2013, 46, 31.  
[6] Lu, W.; Baek, J. B.; Dai, L. (Eds.) “Carbon Nanomaterials for Advanced Energy Systems”, John Wiely &Sons: New York, 2015.
 

Faculty Host: Dr. Doo Young Kim

 

Date:
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Location:
CP-114A/B

Chemistry Department Seminar

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Dr. Song Xu of Keysight Technologies will be presenting a seminar titled Beyond Tapping Mode - Advanced Imaging Modes based on the Oscillation of an Atomic Force Microscope Cantilever.  

Abstract: We will start with discussing the basics of physics and mathematics of the working principle of Atomic Force Microscopes.  The seminar will cover aspects of AFM such as signal driver, the scanning mechanism, the feedback loop and the design concerns, in order to give the audience an overview of the basic principles of this technology.

Tapping mode is a widely used basic imaging mode of Atomic Force Microscopy.   In tapping mode, the cantilever is driven to oscillate up and down at near its resonance frequency by a small piezoelectric element mounted in the AFM tip holder.  An electronic servo adjusts the height of the cantilever to maintain a set cantilever oscillation amplitude as the cantilever is scanned over the sample while the Z movement is recorded as the topographic (height) image. 
 
The cantilever of an atomic force microscope is a very sensitive force sensor. Various short and long range forces allow high resolution mapping not only the physical shape, but also mechanical, magnetic and electrical property.   The forces between the tip and sample could come various physical and chemical interactions, such as electrostatic force, physical repulsive force, van de Waals force, dipole-dipole interaction, magnetic force, chemical bonding, hydrogen bonding, friction etc.  Many advanced imaging modes were developed and continuously been developed to map more physical and chemical information of materials.  In this web seminar, we will introduce many advanced imaging modes based on cantilever oscillating technology. These imaging modes include Phase Imaging, MFM (Magnetic Force Microscopy), EFM (Electrostatic Force Microscopy), KFM (Kelvin Force Microscopy), and frequency modulated Scanning Probe Force Microscopy.  We will discuss the basic physics behind these advanced AC imaging modes, the mathematics of the feedback mechanism and example applications in different research fields.
 

Faculty Host: Dr. Jason DeRouchey

 

Date:
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Location:
CP-114A/B

Arabic Tables

Speak Arabic with Native Arabic Speakers

تحدث باللغة الإنجليزية مع الناطقين بها.

 

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Date:
-
Location:
POT rm 1643

Arabic Tables

Speak Arabic with Native Arabic Speakers

تحدث باللغة الإنجليزية مع الناطقين بها.

Date:
-
Location:
POT rm 113

Language Talk - Episode 3

Our third Language Talk: KWLA podcast, Unwrapping the World Language Program Review, features host Laura Roché Youngworth discussing with Alicia Vinson, Lucas Gravitt, and Lydia Kohler details of the KY Program Review. As they “unwrap” the terminology of the PR, they share their understandings of Regular and Routine, Global Competency, Job-embedded, performance goals, etc. and share examples of how these are being implemented across the state.

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