Crystal growth is one of the most fundamental processes in all of science. Understanding of crystal growth mechanisms has changed dramatically over the past two decades. The recognition that growth does not only occur atom by atom, but can proceed via oriented fusion of crystalline nanoparticles was significant. Recently, many new contributions have expanded the catalog of pathways, altered thinking about nucleation theory and provided new insight into biomineralization processes. Most important are publications on pre-nucleation clusters, amorphous particle-based growth, and mis-oriented nanoparticle growth. We propose to counter this diversification in thinking by arguing for a unified view of all aggregation-based crystal growth and will present a conceptual model that leverages very recent experimental and theoretical results to propose explanations for several of the current unresolved questions in the field.
Biography:
Jill Banfield received her Ph.D. in 1990 and has held appointments at the University of Wisconsin-Madison, The University of Tokyo and at UC Berkeley. Currently, she is a Professor in the Departments of Earth and Planetary Science, Environmental Science Policy and Management, and Materials Science and Engineering. She is also a Faculty Senior Scientist and Lawrence Berkeley National Laboratory.

Learning from nature is a constant principle because nature provides us with numerous, mysterious properties that have developed over millions of years of evolution. Recent achievements include the following: (1) Original studies of the super-wettability of natural systems. (2) Creative approaches in design and fabrication of bioinspired smart interfacial materials with super-wettability. (3) Technology transfer of research findings in the laboratory to practical products.This talk is based on bio-inspired micro/nano-structured interfaces with special wettability, showing from lotus leaves, rice leaves, butterfly wings, water strider legs, mosquito eyes, to spider silk and cactus, revealing that the bio-inspired system not only presents new knowledge, but also has great prospective applications.
Biography:
Lei Jiang received his B.S. degree in physics in 1987, and an M.S. degree in chemistry in 1990 from Jilin University. From 1992 to 1994, he studied at Tokyo University as a China-Japan joint course Ph.D. student and received a Ph.D. in 1994 from Jilin University. He then worked as a postdoctoral fellow at Tokyo University. In 1996, he was a senior researcher at the Kanagawa Academy of Sciences and Technology. In 1999, Jiang joined the Institute of Chemistry, Chinese Academy of Sciences (CAS) as a professor where he presently serves. In 2008, he set up the School of Chemistry and Environment at Beijing University of Aeronautics and Astronautics and also served as dean. He was elected an academician of the CAS in 2009 and The World Academy of Sciences (TWAS) in 2012. In 2010, he held the honor of Fellow of the Royal Society of Chemistry. Jiang also serves as a co-chairman of small and various editorial advisory boards that include Advanced Functional Materials, Advanced Materials Interfaces, Soft Matter, NPG Asia Materials, Biomicrofluidics, Nano Research, Journal of Inorganic Biochemistry and Materials Research Innovations. He received many awards, including the TWAS Chemistry Award in 2011 and the Heliang-Heli Prize in 2013.
Jiang's scientific interest focuses on bio-inspired interfacial materials with super-wettability. He has published two books, three book chapters and more than 400 SCI journal articles, which include publications in Nature (2), Nature Nanotechnology (1), Nature Materials (1), Nature Communications (2), Chemical Society Reviews (5), Accounts of Chemical Research (4), Angewandte Chemie International Edition (25), Journal of the American Chemical Society (22), and Advanced Materials (65). His work has been cited more than 23,000 × the H index is over 70. Jiang is focused on transferring research findings in the laboratory to practical products in the market. He holds 40 granted patents, 56 pending patent applications, and co-founded three technology companies.

In Feynman&’s famous 1959 lecture “There&’s Plenty of Room at the Bottom,” he challenged us to improve the electron microscope 100 times, so we could “just look at the thing.” Are we there yet? With the spectacular advances in aberration correction of the last decade, we have improved image resolution to well below 1 Å and gained sensitivity to light atoms in both imaging and spectroscopy. But today&’s microscope is only 20 times better than in Feynman&’s time - and so we remain far from fulfilling his dream. We cannot just look at point defects and determine their three-dimensional configuration, or their diffusion pathways. Our lateral resolution still far exceeds the fundamental limit set by thermal vibrations, and our depth resolution remains in the nanometer range. In this talk I will show examples where further improvements in resolution would indeed enable us to “just look at the thing.”
Biography:
Stephen J. Pennycook is a Professor in the Dept. of Materials Science and Engineering, University of Tennessee and the Dept. of Materials Science and Engineering, North Carolina State University. Previously, he was Corporate Fellow in the Materials Science and Technology Division of Oak Ridge National Laboratory and leader of the Scanning Transmission Electron Microscopy Group. He received his PhD in physics from the Cavendish Laboratory, University of Cambridge in 1978. Pennycook is a Fellow of the American Physical Society, the American Association for the Advancement of Science, the Microscopy Society of America, the Institute of Physics and the Materials Research Society, and is recipient of the Microbeam Analysis Society Heinrich Award, the Materials Research Society Medal, the Institute of Physics Thomas J. Young Medal and Award and the Materials Research Society Innovation in Characterization Award. He has 38 books and book chapters, over 400 publications in refereed journals and has given over 200 invited presentations on the development and application of atomic resolution Z-contrast microscopy and electron energy loss spectroscopy.

Cathodoluminescence (CL) is the radiation emitted by a material under high-energy electron (cathode-ray) irradiation. Historically, CL has been used by geologists to characterize minerals, as these emit a characteristic optical spectrum when irradiated in a scanning electron microscope (SEM). Most recently, it is being realized that CL offers a very powerful method to study optical phenomena at the nanoscale. In CL imaging spectroscopy, an electron beam is raster-scanned over a sample and an optical excitation map, reflecting the local optical density of states, can be made at a resolution determined by the spot size of the electron beam (<10 nm), more than 20 times smaller than the diffraction limit in a conventional optical microscope. In angle-resolved CL spectroscopy, the angular radiation distribution of nanophotonic structures can be precisely determined and momentum spectroscopy can be carried out allowing for the (spatially-resolved) reconstruction of the optical band structure. The new Angle-Resolved Cathodoluminescence Imaging Spectroscopy (ARCIS) technique is enabled by a specially designed piezo-electric sample stage, a parabolic light collector that is placed inside the electron microscope, and an optical detection and imaging system. It operates over the entire UV-VIS-NIR spectral range (350-1700 nm). We will demonstrate the use of the ARCIS technique in studying the radiation profile of optical antennas, cavity modes and band structure of photonic crystals, dispersion of surface plasmon polaritons, electric and magnetic modes in dielectric Mie resonators, and Purcell effects in plasmonic nanocavities, all at deep-subwavelength resolution.
Biography:
Albert Polman is a scientific group leader at the FOM Institute AMOLF in Amsterdam, The Netherlands, where he heads the program “Light management in new photovoltaic materials.” He is a professor of photonic materials for photovoltaics at the University of Amsterdam. Polman obtained his Ph.D. degree from the University of Utrecht in 1989. He was a postdoctoral researcher at AT&T Bell Laboratories until 1991 and then became a group leader at AMOLF. In 2003, he spent a sabbatical year at CALTECH; from 2006 to 2013 he served as director of AMOLF. Polman's research focuses on nanophotonics: the control, understanding and application of light at the nanoscale, with special emphasis on light management in solar cells and optical metamaterials. He is the co-founder of Delmic BV, a start-up company that commercializes the ARCIS technique. Polman is a member of the Royal Netherlands Academy of Arts and Sciences, a Fellow of MRS and recipient of an ERC Advanced Investigator Grant (2010), the ENI Renewable Energy Prize (2012) and the Physica Prize of the Dutch Physical Society (2014).

Many chemical technology processes take place at the atomic level in gas or liquid environments at elevated temperatures. Understanding and control of complex chemical reactions on the atomic scale are crucial for the development of improved processes and materials. The development of the first atomic resolution environmental (scanning) transmission electron microscope (E(S)TEM) is described [1-6] for the direct visualisation of individual atoms in gas-solid reactions in the working state in real time [3-6], opening up striking new opportunities for studies of chemical reactions at the atomic level. Benefits include new knowledge, improved and more environmentally friendly technological processes for healthcare and renewable energy as well as improved or replacement mainstream technologies in the chemical and energy industries.
1. P.L. Gai, et al: Solid state defect mechanisms: implications for selective oxidation; Science 267 (1995) 661.
2. E.D. Boyes and P.L. Gai, Environmental-HRTEM and applications to chemical science, Ultramicroscopy 67 (1997)219.
3. P.L. Gai and E.D. Boyes, Advances in atomic resolution-ETEM and 1Å aberration corrected in-situ EM ;
Microscopy Research and Tech. 72 (2009) 153.
4. E.D. Boyes, M. Ward, L. Lari and P.L. Gai, ESTEM imaging of single atoms in controlled temperature and gas environments in catalyst reaction studies;
Ann. Phys. (Berlin) 525 (2013) 423.
5. P.L. Gai, L. Lari, M. Ward and E.D. Boyes, Visualisation of single atom dynamics and their role in nanocatalysts under controlled reaction environments:
Chemical Physics Letters, 592 (2014) 355.
6. E.D. Boyes and P.L. Gai, Visualising single atoms under controlled conditions, Advances in atomic resolution E(S)TEM.
Comptes Rendus Physique (editor: C. Colliex), Jan. 2014. doi.org/10.1016/j.crhy.2014.01.002
Biography:
Professor Pratibha Gai is Founding Chair Professor of Electron Microscopy, Professor in the Departments of Chemistry and Physics and Co Director of the Nanocentre (which she helped to create) at University of York, UK. She joined University of York in 2007 from DuPont, USA and University of Delaware, USA, where she concurrently held senior positions as DuPont&’s Research Fellow and adjunct Professor of Materials Science, respectively. Before this she established and led the Catalysis and Surface Reactions Group in the Department of Materials, University of Oxford. She graduated with a Ph.D. in physics from the University of Cambridge, UK. She has pioneered the development of atomic resolution environmental (scanning) transmission electron microscope (E(S)TEM) which enables the human eye to directly visualize gas molecule-solid surface chemical reactions at the atomic level, in collaboration with Prof E D Boyes. The development is providing a better understanding of atomic scale chemical reactions, leading to new medicines, environmentally friendly biofuels and improved industrial products for the benefit of humanity. The atomic resolution-ETEM development is adopted for commercial production and used by researchers worldwide. For her contributions, she has been recognized by awards including, the 2013 L&’Oreal-UNESCO Women in Science Award for excellence in the in Physical Sciences in Europe as the 2013 Laureate for Europe and the Gabor Medal and Prize of the Institute of Physics (UK). She has published nearly 300 papers, books, patents and has presented invited lectures worldwide.

Second generation solar cells based on thin films of polycrystalline semiconductors promise to reduce the cost of sunlight-to-electricity conversion compared to first generation crystalline silicon. Efficient thin-film absorber materials can fulfill the multiple roles of light-absorption, charge separation, and transport of both holes and electrons out of the device. A third generation of materials, which can be processed with solution-based techniques at low-temperature, such as printing, should ultimately lead to the least expensive solar cell technology. However, most of the materials processable with the lowest cost methods usually require complex architectures of distributed heterojunctions to ionize tightly bound electron-hole pairs. This inherently introduces losses at the high density of internal material interfaces. Recently organometal halide perovskite absorbers have emerged as efficient solar cell materials, which seem to be both simple to process and promise to reach the highest efficiencies. This paradigm shift arguably represents a fourth generation of photovoltaics. Snaith will underline the motivation behind nanostructured solar cells, and show some recent advances in simultaneously controlling mesoscopic length-scale order and material crystallinity for solid-state dye-sensitized solar cells. He will then present organometal halide perovskite solar cells, which have rapidly evolved from a nanostructured solar cell to a solid thin film material, with power conversion efficiencies exceeding 16%. He will share recent results on improving and understanding perovskite solar cells, with both device-based and spectroscopic investigations, and highlight some of the reasons why these materials work so well and the future prospects.
Biography:
Henry J. Snaith is a professor in the physics department of Oxford University. He received his Ph.D. in 2004 from the University of Cambridge, United Kingdom, and undertook his postdoc at the École Polytechnique Fédérale de Lausanne, Switzerland. His research has been focused on new materials and device architectures for future generation low-cost photovoltaic. Snaith's achievements include the first demonstration of “gyroid” structured titania for dye solar cells, the first demonstration of mesoporous single crystals of anataze TiO2 and the recent discovery of high efficiency solid-state organometal trihalide perovskite-based thin film and mesosuperstructured solar cells. He was awarded the Patterson Medal of the Institute of Physics in 2012, and named as one of “Natures Ten” people who mattered in 2013. In 2010, he founded Oxford Photovoltaics Ltd., which is commercializing perovskite solar cells for building integrated and utility scale photovoltaic applications.