BNL Home
February 2017
Sunday Monday Tuesday Wednesday Thursday Friday Saturday

1

  1. Center for Functional Nanomaterials Seminar

    1 pm, CFN, Bldg. 735, conf. rm. A, first fl.

    Hosted by: 'Deyu Lu'

    Energy level alignment and geometric structure of organic chromophores at metal and oxide semiconductor surfaces play a critical role in photo-induced charge transfer and barriers to interfacial charge transport. We have performed systematic studies of a series of organic molecules at the TiO2(110) and at noble metal surfaces to understand the origins of energy level alignment and the relevant molecule-molecule and molecule-surface interactions that generate self-organization of these molecules at these surfaces. Combining scanning tunneling microscopy as a local probe of the molecular adsorption configuration with x-ray, ultraviolet and inverse photoemissions as probes of the electronic structure we have compared preparing monolayer molecular systems from sub-monolayer to monolayer coverage ("bottom-up") to forming a monolayer by desorption of a molecular multilayer ("top-down"). For each the metal systems, we find that the molecular monolayer assumes a metastable structure when prepared at room temperature, which converts to a different minimum energy state after annealing. Moreover, further annealing leads to a transition from intact molecular adsorption to dehydrogenation and subsequent rehybridization. This rehybridization is both intramolecular, with a flattening of the molecules and a measurable alteration of the electronic structure, and intermolecular leading to 2D-growth of extended covalently bound structures as shown in the figure. These results suggest it is possible to create ordered 1D or 2D covalently-bonded structures through direct chemical reactions at the surface. When adsorbed on TiO2(110), the chromophores align themselves along the bridging oxygen rows of this surface. However, the energy level alignment depends on both the surface concentration and electronegativity of the organic chromophore, potentially inducing important band bending in the oxide semiconductor. This work was funded by NSF and DOE. Host: Dey

2

  1. Center for Functional Nanomaterials Colloquium

    4 pm, CFN, Bldg 735, 2nd Floor Seminar Room

    Hosted by: 'Deyu Lu'

    Anatase is the form of TiO2 that is most widely used in photocatalysis and solar energy conversion. Anatase is also more active than rutile for most photocatalytic reactions, which has been attributed to various reasons such as the longer charge-carrier lifetime, the higher charge-carrier mobility, and the higher production of reactive OH radicals. In this talk I shall present recent applications of first principles electronic structure calculations and molecular dynamics simulations to study the structure and chemistry of anatase surfaces, with focus on their interactions with water and molecular oxygen, the influence of charge carriers on the reactivity, and the different behaviors of anatase and rutile.

3

  1. Center for Functional Nanomaterials Seminar

    11 am, Bldg 735, Conference Room A, 1st Floor

    Hosted by: ''Dmitri Zakharov''

    SerialEM is software developed for automated acquisition of TEM data developed by the Mastronarde Group at the University of Colorado Boulder. It is compatible with most of the modern TEM platforms and interfaces with a wide range of detectors from CCD, CMOS, direct detectors and STEM detectors from different manufacturers. Originally designed for acquisition of tilt series for electron tomography of (biological) specimens, SerialEM can be used for numerous different acquisition strategies due to many built-in high level commands and a flexible scripting language. Examples include the automated, large scale acquisition of high quality cryo-TEM data for molecular reconstruction or the interface with the Leica EM CRYO-CLEM system. Guenter's presentation will give a short overview on the background of SerialEM, it's user interface and basic operation, and the more complex functionalities including the navigator and the scripting language.

4

  1. No events scheduled

5

  1. No events scheduled

6

  1. No events scheduled

7

  1. No events scheduled

8

  1. No events scheduled

9

  1. No events scheduled

10

  1. No events scheduled

11

  1. No events scheduled

12

  1. No events scheduled

13

  1. No events scheduled

14

  1. No events scheduled

15

  1. No events scheduled

16

  1. No events scheduled

17

  1. No events scheduled

18

  1. No events scheduled

19

  1. No events scheduled

20

  1. No events scheduled

21

  1. No events scheduled

22

  1. No events scheduled

23

  1. No events scheduled

24

  1. No events scheduled

25

  1. No events scheduled

26

  1. No events scheduled

27

  1. No events scheduled

28

  1. No events scheduled

  1. MAR

    16

    Thursday

    CFN Colloquium

    "Tricking Block Copolymers into Forming New Morphologies"

    Presented by Kevin Yager, CFN / BNL

    4 pm, CFN, Bldg 735, 2nd Floor Seminar Room

    Thursday, March 16, 2017, 4:00 pm

    Hosted by: 'Oleg Gang'

    Block copolymer self-assembly allows the rapid formation of nanostructures over wide areas. Yet, the range of possible patterns is fairly limited. I will present emerging strategies for constructing three-dimensional nanostructures whose shapes and symmetries go beyond those of the bulk equilibrium diblock copolymer phase diagram. Photo-thermal methods are used to accelerate assembly, and control block copolymer ordering and orientation. Self-assembly is known to be pathway-dependent, which can be exploited to select a particular nano-pattern. Ordered layers can be stacked to yield new lattice symmetries. This multi-layered ordering can be performed in a responsive mode, where each self-assembled layer templates the ones that follow. Taken together, these new motifs point towards the ability to construct designed, multi-functional 3D nanostructures.

  2. APR

    6

    Thursday

    CFN Colloquium

    "TBD"

    Presented by Carl Mesters, Shell

    4 pm, Bldg 735, Seminar Room, 2nd Floor

    Thursday, April 6, 2017, 4:00 pm

    Hosted by: ''Dario Stacchiola''

    TBD

  3. APR

    27

    Thursday

    CFN Colloquium

    "TBD"

    Presented by Yugang Sun

    4 pm, CFN Bldg 735, Seminar Room, 2nd Floor

    Thursday, April 27, 2017, 4:00 pm

    Hosted by: ''''Fang Lu''''

    TBD

  4. MAY

    11

    Thursday

    CFN Colloquium

    "TBD"

    Presented by TBD

    4 pm, CFN, Bldg 735, 2nd Floor Seminar Room

    Thursday, May 11, 2017, 4:00 pm

    Hosted by: ''TBD''

  5. JUN

    1

    Thursday

    CFN Colloquium

    "TBD"

    Presented by Kyoung-Shin Choi

    4 pm, CFN, Bldg 735, 2nd Floor Seminar Room

    Thursday, June 1, 2017, 4:00 pm

    Hosted by: '''''Mingzhao Lu'''''

  6. JUL

    6

    Thursday

    CFN Colloquium

    "TBD"

    Presented by TBD

    4 pm, CFN, Bldg 735, 2nd Floor Seminar Room

    Thursday, July 6, 2017, 4:00 pm

    Hosted by: 'TBD'