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April 2010


Having overslept, I rushed to the first talk this morning on metamaterials and fortunately caught the second half of the invited talk on superlens. Honestly, I was a bit disappointed that Prof. Xiang Zhang didn't come to give the presentation himself, but the speaker who substituted him did a very good job in describing the groundbreaking work on subwavelength imaging using metamaterials. Sometimes, big names in science are chased after the same as celebrities are in Hollywood. The difference is that the former is mostly about substance while the latter is mostly about style.

Metamaterials has easily grabbed attention of mass media mostly because of its theoretical possiblity of producing invisibility cloaks, a mainstay of science fictions and fantasy novels; just think about Harry Porter's invisibility cloak. However, a less charming concept, superlens, was much more likely to be realized in practice in near term. The idea of seeing nanometer sized objects using visible light is thrilling enough to anyone working on nanomaterials. In addition to that, as one move away from electron microscopy to optical microscopy, common spectroscopy tools becomes powerful accessory to the superlens. One might imagine that UV-Vis-IR spectroscopy becomes available in a optical superlens, just as the way that a EDX does in a electron microscopy. This is exactly what the second speaker of the session demonstrated: a way to combine infrared superlens microscopy and infrared spectroscopy so that one obtains shape information as well as compositional information at the same time.

Once again, seeing physicists and electrical engineers playing around fascinating concepts like invisibility cloaks and superlens, I cannot help but wondering what a synthetic chemist can contribute to this field?

On to the weekend!

What a great end to the conference!  The thermoelectrics characterization session was very interesting although attendance was sparse.  Patrick Hopkins's talk on determining electron-phonon nonequilibrium was particularly outstanding.  We've seen a lot on electron-electron and phonon-phonon interactions, but he forays (experimentally!) into the super short timescale interaction between the two energy carriers.  Neat. 

I hope you all had a great time at the conference.  If you are sticking around for the weekend, there are a bunch of events going on.  The Giants baseball season started today, and there are games this weekend.  There's also a Sunday Streets event which is a great way to see part of the city.  You can also check out this previous blog post for other things to do in San Francisco. 

Have a great trip home!


Beyond the posters

I went to Thursday evening's poster session wanting to see three specific posters, but I only made it to two.  I got sidetracked by conversations with other grad students, and I'm the better for it.  It's nice to hear perspectives on PhD programs, career decisions, and even leisure time activities from people outside of my little circle.  It helps broaden my outlook and keeps me grounded.  To the authors of the that ZnO nanowire poster I never managed to see, maybe we'll cross paths in the future.  Meanwhile, thanks to the several new researchers I met yesterday who pulled me out of my research bubble for a couple of hours.

Today is the last day of the conference, and I've been waiting all week for this afternoon's talks in session DD12 (more thermoelectrics!).  We're almost to the end!  I'll write one more post... hopefully, before I enjoy a post-MRS happy hour.


Thursday Wrap Up

The Talks

Ald There weren't too many talks related to my field so I spent the day meandering around, attending talks that interested me. The most interesting talks for me were on different uses of Atomic Layer Deposition (ALD). The majority of my undergraduate research was on ALD and using it as a way to create the photonic crystals seen in the image on the right. I think ALD is a process that is going to become more and more important as the nano-structuring trend in materials research continues. There really is no other technique that offers the same capabilities as ALD.

Symposium X

Recyle Once again I attended symposium X today and it was great to get a break from technical materials talks and sit in on something that discusses the bigger picture. Today's talk was titled "Confronting Resource Depletion and Energy Consumption from Materials Production: Challenges and Opportunities for Materials Recycling." The speaker was making the argument that recycling materials is one of the primary ways that we can battle the current environmental/energy crisis. And, as researchers even we should be keeping recyclability in mind when developing new materials. I think he has a very legitimate concern since often materials that cannot be recycled are cheaper and easier to develop. 

exhibit at MRS


I used three of Bruker's machines, the one behind the two gentleman is the latest version of D8, a machine specialized for thin film samples. I was amazed by its completely fool-proof magnetic beam alignment assembly. Or to be more precise, one doesn't need to align, just put pieces together and each part will stick to the other correctly by magnetic force. Oh... now think about the amount of money our lab has spent on having field engineer to come over for beam alignment. Is there any way to update from old ones to this one? I asked. "No." ....


furnace, furnace, furnace. Programmable, high vacuum furnace.


With no offense at all, the claim by the poster is outrageously bold: "When the problem involves materials, the solution is ASM. "

Besides talks and poster sessions, MRS is also a marketplace for various companies and publishers to display their latest products. Wandering around various company booths, I was amazed at all the new functions that a seemly simple machine can have, (and secretly how they keep upgrading and keep us buying, just like Microsoft).



From high speed transistor to single molecule detection, is there anything this guy cannot do? (Image credit: wikimedia commons)

Today is my graphene day. Unlike most of the other nanomaterials, such as nanodots, nanorods, nanowires and nanoporous materials, whose synthetic investigation well preceded application-orientated studies, graphene was born with a goal in mind: electronics. Touted as THE next generation electronic materials, THE replacement of silicon-based electronics, graphene was aggressively pursued by industrial labs immediately after the discovery in university labs. IBM recently demonstrated 100GHz transistors wafer scale graphene. (Our labtops or desktops are working at only about 1-3GHz.) Predictions by theorists on electronic, optical, and mechanical properties  expressed in superlative terms gave everyone an impression that a new age has dawned.

Something is missing here. What? Chemistry. And today's first session on graphene is titled Chemistry of Graphene. The synthesis of high quality graphene is still a challenge, and the next two sessions were on the synthesis of graphene, first from epitaxial growth on SiC and the second from exfoliation. The day ended with a mind-blowing transmission electron microscopy movies (yes, movies not images) on graphene and nanoparticles or guest atoms. After the day, I am still left with the question: what can a chemist do about graphene? It is a totally different monster than any other large molecules that chemists ever dealt with. And I guess any existing protocols on double bond or aromatic structures needs to be at least modified. Or there should be a paradigm shift in thinking: we should not deal with the reactivity of a single bond any more, instead, an ensemble of bonds.

Germination Period

Back at it on conference Thursday. I started early again, making it for the first talk in II, charge transport in organic semiconductors. I was hoping to because it was being given by a collaborator in my research group, including some of my own work, so I wanted to see if any killer questions came up. Perhaps it was the fact that the sun was still yawning itself, but the talk was a bit sparse compared to some of the later morning or afternoon talks. The speaker did very well, but other than one person, the rest of us looked a little zombified. But I'm glad I made it, even if just for moral support.

I spent the day migrating between GG and HH listening to speakers discuss competing theories on limitations to achieving high efficiencies in organic photovoltaics. The constant discussion and similar topics just reinforced the fact that the question is still open and debatable. Perhaps in future MRS symposia we will all look back and wonder why there was ever any debate on the predominant recombination methods in bulk heterojunction organic photovoltaics, but for now, it's clear only that more work needs to be done, especially with the recently discovered systems with the record efficiencies. Some might be discouraged by this, I like to think of it as job security.

With the constant stream of information, it's quite hard to take it all in and process it on real-time. I feel I need some time to allow the information I've heard to sink in and take root. The seeds have been planted, it's time for the idea germination period to begin. Today's seeds become tomorrow's saplings and on and on to becoming next year's talks and posters. I hope I'm on the seed distribution side next time.

- Jason

Small nano, big nano

I spent most of the day in the thermoelectrics symposium on superlattices, nanowires, and nanoparticles.  Now, I'm as fascinated by nano-everything as much as the next gal/guy, but the practical side of me always has a nagging question...  how do we make small nano into big nano?  Those tiny things with marvelous properties are all well and good, but we ultimately need devices that we can slap onto cars, stick into computers, and incorporate into all kinds of other large-scale systems.  And then, in the midst of talks describing superhuman feats of fabricating, suspending, measuring teeny tiny samples, came the big nano talk. Tim Huesler of the Institute of Energy and Environmental Technology in Germany described his group's progress on making silicon nanoparticles on a large scale ("Synthesis of Nano-sized Silicon Particles for Use as Ecological Thermoelectric Materials").  They don't just make blocks of this material a few mm on a side.  Oh no.  They have a production plant, and they can make a lot of it.  Ok, ok, maybe they haven't quite done all the characterization they need to do.  I'm sure they'll get to it.  Nonetheless, the promise of nanostructured thermoelectrics produced on a large scale was exciting, and I can't wait to see more progress in this area.

On another note, I slipped out of the thermoelectrics symposium to see Jeffrey Grossman's talk, "Understanding and Prediction of Materials Properties for Energy Conversion and Storage" in the computational approaches symposium.  I don't do this type of computational work, so I don't know the details of how he computes these novel material properties.  I can say I like the way this guy thinks and expresses his thoughts.  His intellectual curiosity and willingness to ask "But what if?  Let's just see..." were really exciting.

Looking forward to the poster session tonight!


Poster Session and The FREE food!!


Wednesday Session

FREE food in the Wednesday Poster session

More free food on Wednesday Poster session

THE OPEN BAR on Wednesday Poster session

If you are a grad student, you know how much you like free food. And if you read PHD comics, you know how universal that liking is for all grad students. So I was a bit disappointed on Tuesday that neither the talk nor the poster session provided enough food for everyone. During the poster session on Tuesday, the food was gone after half an hour, and if you were not lined up at the beginning, chances were that you would not get any. What's more, the food is always cheese, fruit, and vegetables (I know I shouldn't complain as long as they are free, but...). However, the situation is totally different on Wednesday, real all-you-can-eat dinner and a open bar, and the amount is unlimited! 

Something about the poster session itself. Even though the session today has nothing to do with what I am researching, I still find several posters intriguing. One of them is on using PEG modified extracelluar matrix to enhance the diffusion of nanoparticles. Normal approach is to coat the nanoparticles, but since the surface of the nanoparticle is precious for other functionalization, the author chose to functionalize the extracellar matrix. I enjoyed listening to the author describing the thinking behind this shift. It made me think whether similar thinking pattern can be applied to my research. Also enjoyable in the poster session is the hand-shaking: one will meet a couple of old colleagues and hopefully make some new friends. 

For free food or for hand-shaking (a.k.a, networking) and for looking for inspiration, go to the poster sessions!!

Mastering Science Presentations


I sat almost all day where I suppose to stay, the symposium F, Materials, Process, Integration and reliability in Advanced Interconnects of Micro- and Nanoelectronics (what a long name!). I thought I might be the only chemist in the room until I talked with the speaker before my presentation during the afternoon session and found out that she is also a chemist, physical chemistry though. My job today (at the time writing this post it is already yesterday, but you know what I mean) is to introduce the type of materials that I have been working on to the semiconductor industry. After my presentation, I was telling myself "hmm, probably it would be better if I did this or that or this", and then I got confused by myself, so I went to this tutorial session held in the evening titled "Mastering Science Presentations".

The speaker, Tim Miller, a consultant from Spoken Science, discussed some universal principles and some guidelines, or 1st approximation laws as he called it, particular for science presentations. Two things stood out. First is belly breathing, or gut breathing or ab breathing, whatever name you like to call it. It is almost the same as the kind of techniques used by Buddhists or Taiji or several other east Asian martial arts practitioners. The technique is simple, but powerful, especially in maintaining self-control and conquering stage-fright. The second is the use of black background instead of white background during a ppt slide, especially if you want to emphasize the message you want convey. The argument behind sounds intuitive: black in computer screen means nothing, whereas white on a piece of paper means nothing. There is also a practical reason. Having a black background will prevent the situation where the speaker drops shadow on the screen unintentionally. Hence This vs. That in the image of this post.

Other universal principles covered include a) know thy audience, b) tell a story, c) make eye-contact, and d) speak slowly. Other guidelines for science presentation particularly include a) an image worth a thousand words b) use call-off arrows and circles c) repeat the question the audience asks before answering.