Highlights of Recent Research Activities

 

Self-assembly of nanostructures are of both fundamental and technological interest as the well-defined ensembles display the collective properties that are different from those of individual units and bulk materials with the same chemical composition. My research therefore is focused on the synthesis of new classes of nanostructures and mesostructures, with an emphasis on developing new synthetic approaches and understanding the fundamental issues of structural assembly and crystal growth. I am interested in several physicochemical properties in optics, biosensor, catalyst, as well as mechanics which can be widely and easily tuned by adjusting their composition, size, shape, crystal structure, and configuration of assembly. Specifically, my research topics include:
 
  • The particle mediated self assembly in mesocrystals and mesostructures

Recently, a new growth mechanism, i.e. the non-classical particle-mediated crystallization pathway was deduced by H. Cölfen et al. from biomineralization processes. This particle-by-particle growth process always involves the oriented attachment and/or grain rotation of the building units and results in the formation of so-called “mesocrystals” via the mesoscale transformation. Mesocrystals are ordered mesoscale superstructures composed of individual nanocrystals that are aligned along a common crystallographic direction, exhibiting scattering properties similar to the ones of a single crystal. In my previous works, I firstly reported the mesotransition phenomenon in metals which represents an important proof for the nonclassical crystallization pathway for single crystals via mesocrystal intermediates. In the following experiments, I synthesized various kinds of mesostructures. Representative publications: Chem. Soc. Rev.,2011, 40, 5347; Nanotoday, 2010, 5, 175; Chem. Commun.2009, 1130; CGD 2008, 8, 3616; APL 2008, 92, 173120; CGD 2007, 7(5), 864-867; APL 2007, 91, 083108

 

  •  Optical property (e.g. SPR, SNOM and SERS) of noble metal mesostructures

Various mesostructures including sea urchin-like, flower-like, corrugated nanowire, et al. have been synthesized via above mesoassembly route. Raman spectroscopy measurements indicate that the individual sea urchin-like and multitipped gold mesoparticles exhibit a high SERS enhancement of ~ 107-108. Representative publications: Nanoletters, 2010, 10, 5006; ACS Nano, 2011, 5 (12), 9442; JMC 2012, 22, 1998; Chem. Commun. 2011, 47, 5157; APL 2008, 92, 13115

  

  • Biosensor and cancer early diagnosis using mesostructural nanoparticles

Small size of mesostructures such as sea-urchin Au mesocages with size of ~100 nm, Ag mesocages and Au coated Fe3O4/Fe2O3 compound have been synthesized which is being exploiting for the SERS-based biosensor and the cancer prevention and early diagnosis. Single-molecule behaviors was detected from individual silver cubic mesocage using single particle SERS spectra with crystal violet molecules (1 x 10-11M). Representative publications: Biomaterials, 2011, 32, 4877; some results to be published.

 

  • Mechanical and magnetic properties of amorphous nanomaterials (called mesoglasses and nanoglasses)

Nanoglasses are solids consisting of nm-sized glassy regions connected by interfaces having a reduced density. Nanoglasses with tunable material density and atomic structures can be used for to improve all density- and atomic-structure dependent properties, e.g. mechanical, optical, electrical properties. Representative publications: Nanoletters, 2012, 12 (1), 458; Recently, we observed the mesoassembly process during the solution synthesis of amorphous nanoparticles, we called mesoglasses. Typical results to be published. 

 

 

 

Research Grants and funding

 

  •   National Natural Science Foundation of China (NSF) (51171139), RMB 600,000, 2012~2015
  •  “New century outstanding talents” by the Ministry of Education of China (NCET), RMB 500,000, 2011~2014
  •   Scientific New Star Program in Shann Xi Provience, RMB, 100,000, 2012-2014
  •   Doctoral Funds for New Teacher, Ministry of Education of China (NCET), RMB 40,000, 2012~2014
  •  Tengfei Talent project of Xi’an Jiaotong University, RMB 500,000, 2011.06~2014.05
  •   The New Teacher Fundamental Research Funds for the Central Universities, RMB 300,000, 2010-2013
  •  Alexander von Humboldt fellowship foundation, 2009.01-2010.06
  •  The doctorate foundation project, Xi’an Jiaotong University, (No. DFXJTU2005-12) 20,000, 2005.02-2007.02