Research Fields:

• Development and application of scanning probe microscopy
  
  
• Construction, characterization and properties of molecular nanostructures
  
  
• Chemical and physical properties of single molecule
  
  
• Functional nanostructured materials for sensor, energy, environmental, and electronic applications
  
  
• Nanoelectrochemistry
  
  
• Fullerene-based cluster materials
  
  
• Imaging and detecting of single biomolecules
  
  
• Mechanism study in catalysis reaction and sensors

Research Progresses

The NSFC Creative Research Group “Physics and Chemistry of Molecular Nanostructure and Single Molecules” was commenced in 2002, and renewed in 2005. During the past six years, we have always aimed at the scientific targets on investigation of the molecular nanostructure construction and characterizations, the physical and chemical property study of single molecules, and the exploration of biomolecular interaction and reaction at the single molecule level. Since 2005, based on our above-mentioned scientific target and after wide and far discussions about the developing trend of nanoscience in the world, we have concentrated on several research directions as follows: (1). Construction, control, and assembly of nanostructures; (2). The physical and chemical property study of single molecules and biomolecules. (3). Preparation and characterizations of functional nanomaterials. (4). Study of principle nanodevices. (5). SPM and other new technologies on probing nanostructures.

Under the support of the NSFC Creative Research Group funding, We made a good progress in the last three years. 110 scientific papers have been published, some of them in prestigious journals, such as J. Am. Chem. Soc., Angew. Chem. Int. Ed., Adv. Mater., PNAS, Acc. Chem. Res. J. Phys. Chem. B, Anal. Chem., Appl. Phys. Lett., Chem. Comm., Langmuir et al. （in which IF>3: 61 papers, IF>7: 21 papers）. These results attracted considerable attentions in the world and have been widely cited. Moreover, we have also applied for 4 patents and got two high-level domestic scientific awards in the three years.

The research progress and representative research results are summarized as followings:

1. Construction of Molecular Nanostructures

1.1  Assembly of metal-containing complexes

Metal-containing macrocycles with high symmetry and precise architecture are a new class of promising supramolecules for future application in nanotechnology because of their definite shape and size, as well as magnetic, photophysical, and electrostatic properties. The metallamacrocyclic supramolecular assemblies on solid supports are ideal building blocks for constructing molecular nanodevices. Understanding the rules governing their self-organization is significant fundamental steps toward realizing useful nanodevices and nanostructures. This project was focused on the self-assembly structure of a several metal-containing complex and ligands on solid-liquid interface, investigating the effect of different substrates on the assembly, the relation between ligand and complex assembly structures, and the rules for the assembly of complex on solid surface.

1.1.1 The effect of molecular conformations on the self-assembly structure

The well-ordered self-organized molecular architectures were successfully fabricated on a Au(111) surface with three self-assembled supramolecular species with different symmetry and conformations, a rectangle, a square, and a three-dimensional cage. High resolution ECSTM images demonstrated the detailed information of the molecular architectures. This result showed that the assemblies self-organize to form highly ordered adlayers, preserving their spacial conformations. Intermolecular interaction can vary according to molecular chemical structures, leading to self-assembly architecture with different symmetry. The structure of molecular architectures has close relation with the size of molecules. Even similar molecular structure can create different architectures due to different molecular size. Hence, by carefully controlling the size and conformation of complexes, much new molecular architecture may be fabricated. (J. Am. Chem. Soc., 2005, 27, 16279－16286)

1.1.2 The effect of substrate on the assembly architecture of complexes

The effect of substrate on the assembly architecture of Pt-N macrocyclic was studied by STM. The self-organized adlayers of the rectangle were successfully constructed on highly oriented pyrolytic graphite (HOPG) and Au(111) surface. ECSTM research found that the rectangles spontaneously adsorb on both surfaces and self-organize into well ordered adlayers. On the Au(111) surface, the face of the rectangle lays flat on the surface, forming linear chains. In contrast, the long edge of the rectangle stands on HOPG surface, forming a 2D molecular network. This result showed that different substrates can induce different structure for the same molecules due to the variation of molecule-substrate interaction. Hence, by the appropriate choice of substrate materials, we can control the structure of self-organized architecture on solid surface and manipulate the orientation of metal-organic complex to obtain stable ordered architecture, which is hopeful for the application in nanodevices in the future. By comparing the different architectures of metal-organic complex, intermolecular interaction, molecule-substrate interaction and the relation between molecular orientation and substrate have been understood deep, which improve the development of the theory for self-assembly on surface. This result was published on Proc. Natl. Acad. Sci. USA (Proc. Natl. Acad. Sci. USA 2005, 102(4), 971-974). “Materials Today” （2005, 3, 12）reported PNAS paper, stating that it is important for understanding if this finding is only limited to rectangle molecules on the specific surfaces or it is a general phenomenon, which will determine the usefulness of such materials in fabricating surface nanodevices that cannot be prepared by conventional nanofabrication.

1.1.3 Comparison between ligands and their complex

The researchers studied the supramolecular assemblies of a serial of ligand and their complexes in order to find the relationship between these two kinds of molecules. A linear-spacer-bridged BPMmB ligand (bis(pyrrol-2-yl-methyleneamine) consist of double ester substituted pyrrole cycles, one phenyl and double bond N atoms. Three BPMmB ligands can form BPMmB/Zn^II complexes with three Zn^II ions in a triangle shapes by varying the spacer bridges between two pyrrol-2-yl-methyleneamine units. By employing the self-assembly adlayers of BPMmB ligand and its triangle complex were constructed on Au(111) surface. All of the two kinds of molecules formed long range ordered and close-packed adlayers on gold substrate. It can be seen from STM images that the characteristics of BPMmB and the complex on gold is consistent with their chemical structures, especially the triangular conformation of the complex was clearly demonstrated. Although the metal complexes include ligands, the assembled structures and adlayer symmetries of the ligands and complexes are totally different. It should be noticed that the BPMmB ligand and the complex are tend to adsorb on gold with their special orientation which is helpful for resulting in the strongest molecule-substrate interaction. Hence, the ligand was parallel with the substrate, forming lamellar array. Whereas, the triangle complex formed hexagonal assembly networks with the molecular plane of the complex parallel to the underlying Au(111) surface.

1.1.4 Control of supramolecular rectangle self-assembly with a molecular template

Surface-confined molecular assemblies display much greater coherence in their orientation, structure, and, ultimately, function. Earlier studies revealed nanoscale supramolecular rectangles on HOPG s urface fabricated a disordered adlayer. 1,3,5-tris(10- carboxydecyloxy) - benzene (TCDB) is a derivative of trimesic acid a nd can form two-dimensional network HOPG with well-defined nanoscale cavities. We have successfully controlled the self-assembly and monodisperion of a well-ordered array of supramolecular rectangles on HOPG using a TCDB template. This method provides a facile approach to surface modification and the fabrication of 2D assemblies. （J. Am. Chem. Soc., 2007, 129, 9268）

Based on above research results, the researchers concluded that on gold surface, the principles for the assembly of complexes are as follows:（1）Molecular size and conformation play important roles in the self-organized architecture of complex. By varying the size and conformation of complexes with similar chemical structure, the interaction between molecule and substrate can be controlled, subsequently the assembly structure can also be controlled.（2）By appropriate choice of substrate, molecule-substrate interaction can be changed to control the structure of self-organized architecture on solid surface.（3）Although there is correlation between the chemical structures of ligands and their complexes, no stable relation can be determined on their assembly architectures on solid surface. (4) By using the molecular template, surface modification and the fabrication of 2D ordered assemblies can be reslized.

1.2 Functionalized polymers on surfaces

1.2.1 Substituted oligothiophenes

Oligothiophenes are promising candidates in many electronic devices such as light-emitting diodes, thin film field-effect transistors, solid-state lasers, and photovoltaic devices due to there stability, high field-effect mobility, perfection in structural organization. In this project, a series of oligothiophenes with carboxylic groups and alkane chains, TA (3-thiophene acetic acid)、DTDA(2,2’-bithiophene-5,5’-dicarboxylic acid)、TTDA(3’-pentyl-5,2’:5’,2’’-terthiophene-2,5’’-dicarboxylic acid) and QTDA(4’,3’’-dipentyl-5, 2’:5’,2’’:5’’,2’’’-quaterthiophene-2,5’’’-dicarboxylic acid), were synthesized. The molecular architectures by using the so-prepared oligothiophenes on HOPG surface were investigated by scanning tunneling microscopy (STM). It is found that the hydrogen bonding plays an essential role in the formation of the ordered assemblies. No long-range ordered structure exists on the TA adlayer because of strong intermolecular interaction and weak interaction between molecules and substrate. However, DTDA、TTDA and QTDA formed ordered structures on HOPG surface. Due to the direction of H-bongdings, TTDA fabricated several structures on HOPG surface. (J. Phys. Chem. B 2006, 110, 17043-17049， J. Nanosci. Nanotech. In press )

Based on the previous results, two alkyl-substituted dual oligothiophenes, quarterthiophene (4T)-trimethylene (tm)-octithiophene (8T) and 4T-tm-4T, were used to fabricate molecular structures on HOPG and Au(111) surfaces. The resulted structures were investigated by scanning tunneling microscopy. The 4T-tm-8T and 4T-tm-4T molecules self-organize into long-range ordered structures with linear and/or quasi-hexagonal patterns on highly oriented pyrolytic graphite at ambient temperature. Thermal annealing induced a phase transformation from quasi-hexagonal to linear in 4T-tm-8T adlayer. The molecules adsorbed on Au(111) surface in randomly folded and linear conformation. Scanning tunneling spectroscopy measurement showed the electronic property of individual molecules in the patterns. These results were published on Proc. Natl. Acad. Sci. USA.（Proc. Natl . Acad. Sci. USA，2007，104，3707–3712）。“Materials Today” （2005, 3, 12）reported this paper immediately, and ACS website also gave a “heart cut” report on this paper, stating that these results are significant in understanding the chemistry of molecular structure, including its formation, transformation, and electronic properties. They also help to fabricate oligothiophene assemblies with desired structures for future molecular devices.

1.2.2  Monodispersed molecules controlled by the self-assembly structure of OPE

Controllable distribution and dispersion of organic/bio- molecules on solid surface are very important issues in nanomaterials and nanotechnology. Oligo(phenylene-ethynylene) (OPE), is used in preparing molecular wires and molecular template because of its well-defined chemical structure together with its improved solubility and processibility. In this project, by using the self-assembled template fabricated via end-functionalized oligo(phenylene-ethynylene) (OPE), organic semiconductor, coronene (COR), and biomolecules such as tripeptide are well controlled, distributed and monodispersed on highly oriented pyrolytic graphite (HOPG) surface. Within the molecular template, COR molecules were controllably distributed into various arrays just by simply adjusting the molecular molar ratio. Tripeptide TGG molecules were uniformly positioned at vacancies of OPE template. Noncovalent hydrogen bonding plays an important role for the controllable distribution and dispersion. The present method from self-assembly provides a facile way to fabricate ultra-small electronic components, sensing elements, and scaffolds for biomaterial engineering. (J. Am. Chem. Soc. 2006, 128, 12384-12385)。

This project also found that OPE molecular template can be employed to adjusting the assembly structure of other organic moleucles. Both octakis(octyloxy) phthalocyanine (PcOC8) and substituted praseodymium bis(phthalocyanine) (Pr(PcOC8)₂) can form 4-fold or 6-fold symmetrical adlayers on HOPG surface. However, when both molecules were added into the OPE template,  Pr(PcOC8)2 molecules prefer to form an ordered adlayer at the top of the OPE adlayer, while PcOC8 molecules adsorb on HOPG surface directly and form separated domains with OPE. These results may be helpful to construct surface assemblies and develop molecular electronic devices in the future. (J. Phys. Chem. B 2005, 109, 19859-19865)。

1.2.3 Effect of H-bonding on the assembly structure of BF₂-Substituted -Dicarbonyl Derivatives

The role of hydrogen bonding in forming self-assembled monolayers of two BF2-substituted -dicarbonyl derivatives has been studied by scanning tunneling microscopy (STM). Both molecules spontaneously adsorb on HOPG surface and self-organize into well-ordered two-dimensional (2D) lamellae. The hydrogen bonding at different positions is found to have a significant impact on the self-assembled structures. On one hand, the C-H…F hydrogen bonding between the ortho carbon of the phenyl ring and the fluorine of the BF₂ group dominates the formation of the lamellae. On the other hand, the O-H…O hydrogen bonding between the neighboring carboxyl groups doubles the width of the lamella. The present results provide significant information in understanding the noncovalent effect on molecular self-organization.（J. Phys. Chem. In press.）

1.3  Controlling and adjusting molecular nanostructures

1.3.1 Thermal induced molecular trans-to-cis isomerization

The adsorption behavior of bis(4,4’-(m,m’-di(dodecyloxy)phenyl)- 2,2’-difluoro- 1,3,2- dioxaborine) were studied on HOPG surfaces by STM. It was found that the structure of the adlayer can be converted from lamellar to hexagonal through a thermal-annealing process. The hydrogen bonding between the molecules causes a break in molecular symmetry upon adsorption onto the surface and results in chiral assemblies from achiral molecules that were previously clearly observed by STM. For the first time, a thermally induced trans-to-cis isomerization of adsorbed molecules was observed and the thermodynamically stable cis-isomer adlayers were created. Although thermodynamically unstable in solution, the cis isomers become remarkably stable when adsorbed on the HOPG surface. By using only thermal stimulation at different temperatures, pure trans- and cis-isomer adlayers can be obtained. The results were publised on Angew. Chem. （Angew. Chem. Int. Ed.，2006, 45, 3996 –4000）, and were remarked as one VIP paper, stating that Hydrogen bonding (C-H···F) exists within the assembly, inducing a breaking of the molecular symmetry and resulting in chiral assemblies from achiral molecules. For the first time, a thermally induced trans to cis isomerization of the adsorbed molecules was observed and thermodynamically stable cis isomer adlayers were created with symmetry transformation from lamellar to hexagonal. The results provide a promising way to fabricate and control self-assembly with pure trans or pure cis isomers.

1.3.2 Light-induced controlling the molecular adsorption structure  

UV light irradiation effect on the structural transformation in a self-assembled monolayer of 4-(amyloxy)-cinnamic acid (AOCA) on Au(111) has been investigated by using ECSTM. The well-defined 4-(amyloxy)-cinnamic acid adlayer with a (4×11) symmetry on Au(111) is varied into a different molecular arrangement with a symmetry of (5×8) after UV-light irradiation onto the adlayer. This is attributed to a photo-induced dimerizaion occur to AOCA molecules. The direct evidence at molecular level about photodimerization of cinnamic acid on metal substrate is presented.（J. Phys. Chem. B 2005, 109, 14773-14778）

Similar to the study of AOCA molecuels, scanning tunneling microscopy (STM) also has been employed to investigate the photoisomerization of azobis-(benzo-15-crown-5) on Au(111). A self-assembled monolayer of azobis-(benzo-15-crown-5) with a (3×7) symmetry was observed on Au(111). After ex-situ UV-light irradiation, a new adlayer structure with a different molecular arrangement could be seen on Au(111) due to the UV irradiated trans-to-cis structural change. After in-situ UV-light irradiation, the ordered arrays disappeared and many bright clusters emerged at domain boundaries. The results presented here provide direct evidence at the molecular level for a photochemical reaction.（J. Phys. Chem. B 2006, 110, 3185-3188）

1.3.3  Controlling molecular orientation by electrode potential

The adsorption of 4,4’-bipyridine (BiPy) on Cu(111) has been investigated in 0.1 M HClO₄ by cyclic voltammetry, electrochemical scanning tunneling microscopy (STM), and surface-enhanced infrared adsorption spectroscopy (SEIRAS). It was found that diprotonated BiPy, BiPyH₂²⁺, is adsorbed flat on the Cu(111) surface and forms a well-ordered monolayer with a (3×4) symmetry in the double-layer potential region extending from -0.2 to 0.26 V. At more negative potential, BiPyH₂²⁺ is reduced to its monocation radical, BiPyH₂·⁺, and forms another well-ordered structure in which the radicals are stacked in molecular rows with a face-to-face self-dimer as the building unit.（Langmuir 2006, 22, 3640-3646）

2.  Preparation and Characterization of Functional Nanomaterials

2.1  Inorganic semiconductor materials

Inorganic semiconductor materials, including metal oxides and others, have broad applications in catalysis, sensor, semiconductor, photoelectronic devices. When the sizes of metal oxide particles are reduced to nano range, quantum size effect causes the discrete energy states and broaden the band gap. It is also possible to control the size and morphology of these particles, thus generating unprecedented properties. We focused on synthesizing metal oxide materials with micro-nano hierarchical structures and robust mechanical properties, through low cost and low environmental impact methods, and using these materials in catalysis, sensor and pollution abatement. Some of the recent results are summarized below 

2.1.1    Low cost hydrothermal method for metal oxides with large surface area

We used inorganic metal salts (nitride and chlorides) as starting materials to synthesize metal oxides. The main advantage of this method is low cost as chemicals consumed are inorganic salts and urea, while expensive surfactant is recycled. The products usually have large surface area, e.g. iron oxide has a surface area of 170 m²/g, which is larger than most of the reported data. These metal oxides are also highly crystalline and are very stable. Over all morphologies of these materials are flower like particles. We attribute their high thermal stabilities to their hierarchical structure. (Micropor. Mesopor. Mater. 2007, 100, 233；Adv. Mater. 2006, 18, 2426，most-accessed article)

2.1.2 Polyol mediated methods for metal oxides

We also developed a polyol mediated methods to produce hierarchical structured metal oxides, including iron oxide, cerium oxide and Colbert oxide, and studied the detailed mechanisms for the Colbert oxide formation through a concentration controlled process. In these studies, we focus on the relationship between morphology and properties, mechanism of the process and morphology control. （Adv. Mater. 2006， 18， 2426；J. Phy. Chem. B. 2006, 110, 15858; Chem. Mater. 2007, 19, 1648）

2.1.3  Hierarchical structured metal oxides for pollution abatement

Pollutants, such as organic contaminate and heavy metal ions in water, CO in air, pose health risk for the public. Developing affordable materials to eliminate these pollutants, is not only of social benefits, but also of scientific value as how to solve a chemical problem through functional materials. The hierarchical structured metal oxides, with their large surface area and abundant surface hydroxyl groups, can effectively adsorpt organic contaminates; in addition, the lattice of metal oxide crystals can adsorpt heavy metal ions. Due to facile transportation of species on these materials, desired water treatment results are obtained. For example, to remove Cr(VI) ions in water, normal iron oxide shows a 0.7 mg/g capacity, while hierarchical structured iron oxide’s capacity is 4.5 mg/g. 18, 2824. Similar results are obtained with Cerium oxide to remove Cr (VI) and As (III). Note that these metal oxide materials can be regenerated and reused. (Adv. Mater. 2006)

2.1.4 Other semiconductor nano materials

    By simple solution phase route, we produced monodispersed ZnS nanoparticles, each of which is composed of smaller primary building blocks and pores. The materials have large surface area and are very active photo catalyst for degrading the organic pollutants, showing higher activity than that of commercial P25 catalyst and non-porous ZSN nanoparticles of similar sizes. (Angew. Chem. Int. Ed., 2005, 44, 1269 )

2.2 Metallic nanomaterials

u      We developed a template assisted electronchemical methods to prepare a Sn/Pt bimetal nanotube array, which shows very high activity as anode catalyst in direct methanol fuel cell. Potential applications of this material also include catalysis, electroanalysis, chemical sensor, etc. (Adv. Mater., 2005, 17(6), 746-750).

u      We designed and prepared a Ni-Pt bimetal alloy nanowire array using an AAO templated electrodeposition method. The method developed in this work is facile and versatile. The Ni-Pt array shows excellent magnetic properties and has potential to be used in super high density magnetic recording devices. (Inorg. Chem., 2005, 44, 3013)

u      Using simple solution phase route, we prepared gold and Gold/Silica composite void nanospheres. The size of the sphere as well as the void space inside can both be controlled. For Au nanospheres, by tuning the size of the void, we can tune the surface resonance property of the sphere. These materials may be used in photon crystals, plasma, and chemical or bio sensors. Pd, Ru nanospheres with similar structures are also prepared using the same route. (J. Phys. Chem. B. 2005, 109, 7795-7800)

2.3 Carbon materials with novel morphology

   Carbon nano fibers (CNFs) and nanotubes (CNTs) are essential carbon materials. Usually by CVD method, Y branched CNFs and CNTs are produced, ie there are three branches at the junction. We prepared CNFs and CNTs with four branches at the junction, as we call it three dimensional K junctions. Branched CNTs are ideal materials for nano electronic devices and controlled specie transportation. The branches on CNTs can provide channels for transportation, and can serve as the terminal in electronic devices. In this regard, adding one more branches not only adds one more option in device design, but also may introduce new properties. (Carbon 2007, 45, 268)

By controlling the local concentration of acetylene during the CVD process, we produced several carbon materials with novel morphologies, including Y branched carbon nano coils (CNCs), branched CNFs with even length units and half CNF half CNCs hybrid. （JPCC, 2007, ASAP）

2.4 Supported nano noble metal particles

Nano noble metal particles have excellent catalytic properties. Nano gold catalysis is emerging as one of the most actively studied field in recent years. However, nano noble metal particles need to be supported on a stable surface in order to avoid aggregation. How to disperse nano metal particles as well as how to control the disperse state is one of the frontier in catalysis research. We develop a rational route to achieve desirable dispersion state by taking advantage of evenly distributed hydroxyl groups on the supporter surface as the position locater. The interaction between the hydroxyl groups and the noble metal particle precursor results in mono dispersion state. When used as the catalyst for Suzuki coupling reaction, Au/TiO₂ catalyst show excellent activity as well as stability. (Chem. Mater. 2007, ASAP） 

    Another supporting materials we used is hierarchical structured Cerium oxide. The Au/CeO₂ composite material has two outstanding features: first is highly dispersed Au nanoparticles that have high activity; second is the unique micron-nano structured cerium oxide structure that provide strong mechanic properties and facile specie transportation on the surface.（Chem. Mater. 2007, 19， 1648）

We also developed a procedure to load monodispersed Pt nanoparticles on CNTs surface using a mild solution route. Using organic base molecules as transportation vehicles and position agents, in-situ generated Pt nanoparticles are evenly attached onto the CNTs surface. The around of the Pt loading can be readily tuned. These Pt/CNTs composites are excellent catalysts for methanol fuel cell.（J. Phys. Chem. C 2007, 111, 11174）

2.5  Preparation, purification and self-assembly of single-walled carbon nanotubes

SWNTs were synthesized by modified arc-discharge medthod, and then near edge X-ray absorption fine structure (NEXAFS) spectroscopy was used to assist purification of SWNTs. Finally, high purified SWNTs (＞97%) were obtained as revealed by various spectroscopic characterizations. We have also developed a facile procedure for controllable synthesis of SWNTs nanocages by self-assembled technique. The nanocages were built up by pentagons and hexagonals, which were made up of SWNTs bundles. The shape of the nanostructures is very like the model of fullerene, so we named them as nanobuckyballs. The experiment conditions, such as the concentration of surfactant or SWNTs, the quality of SWNTs, the temperatures, and the reaction times, have been investigated in details to reveal the Buckyball formation mechanism.

2.6 Porous material

Methanol to Olefin (MTO) reaction is of both scientific and economic impact. For mechanistic study, a major obstacle is the presence of secondary reactions, which dominate the process and make it difficult to observe primary reaction product. We approach this problem from a new angle by taking advantage of the shape selectivity of zeolite, which has pores in the nanometer range. By choosing zeolite with desired pore size, we can control the extent of MTO reaction, so that secondary is completely suppressed. This enables us to observe the evolution of certain key intermediates. In this work, we use confined space as a tool to control the reaction extent, and to setup desired condition for detailed mechanism study; this is a new and effective approach in catalysis research. (Angew. Chem. Int. Ed. 2006, 45, 6512, VIP paper）。

We use mesoporous silica to modify the electrode for electrochemical analysis of TNT type explosives. Mesoporous silica has large surface area and well defined pore structures in the nanometer range. Electrode modified by mesoporous silica show significantly improved detecting limit. e.g. the detecting limit for TNT is 0.4 ppb, while the decting limit is 90 ppb for bare electrode. We attribute this higher detecting limit to high surface area of the mesoporous silica that can adsorpt TNT molecules and increase the local concentration near the electrode; and the pore that facilate the transportation of the TNT molecules. In addition, we also modified the electrode with CNTs, fullerenes and conjugated aromatics, all resulted in better senstivity. （Anal. Chem. 2006, 78, 1967；Phys. Chem. Chem. Phys. 2006, 8, 3567）

2.7 Oganic Functional Nanomaterials

2.7.1 ZnTPyP

   A new self-assembly technique has been developed to create self-assembled porphyrin hollow hexagonal nanoprisms that can collect into a smectic phase. When zinc meso-tetra (4-pyridyl) porphyrin (ZnTPyP) is suspended in solution with a surfactant molecule, cetyltrimethylammonium bromide (CTAB), the molecules assemble into hollow tubes with a hexagonal cross section. The length of the tubes varies with the relative concentrations of ZnTPyP and CTAB. Furthermore, when the solution is allowed to evaporate, the structures align themselves parallel to each other into a three dimensional smectic suprastructure as a result of dispersivity and regular geometric shape. Such a smectic crystal is intriguing for several reasons. For one, it represents one of the few examples of an organic material that can self-assemble into a secondary structure. Also, porphyrins are interesting because they are biologically compatible and exhibit photochemical activity. The self-assembled structure could be useful for photonic crystals, drug-delivery devices and molecular filters. Owing to the rich catalytic-, photo-, electro-, and biochemical activities, the hexagonal hollow prism-shaped porphyrin nanostructures are expected to be useful in the applications such as catalysis, drug delivery and protection of biological active materials, and might be used as an organic 1D building block to fabricate electronic, optoelectronic and electrochemical nanodevices. The ordered assemblies may opens up exciting avenues for a number of applications from nanoscale optoelectronic devices to catalysis, drug delivery and molecular filtration. Part of the related research work has been published in the Journal of American Chemistry Society (2005, Vol. 127, No. 48, 17090-17095), and highlighted by the important international journal of Photonics Spectra (Photonics Spectra, 40 (1), 26 Jan 2006).

2.7.2 BEDT-TTF

Bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) based charge-transfer salts have exhibited many interesting solid-state physical properties ranging from superconductivity and conductor-to-insulator transitions to antiferromagnetism and ferromagnetism. We combined electrocrystallization which is a common method for the synthesis of BEDT-TTF-based charge-transfer salts with the use of porous anodic aluminum oxide (AAO) template which are ideal host systems for the fabrication of large-area nanostructures. Highly ordered nanotube arrays of a BEDT-TTF based charge-transfer salt were, for the first time, successfully prepared in this way. I–V characteristics of both nanotube arrays and single nanotubes as well as the temperature dependence of the resistance were also measured, showing a low conductivity and metallic transport property of these nanotubes along the axis of nanotube. Related research work has been published in the Advanced Materials (2006, 18, pp.2753) and was highlighted by scientific website www.frost.com.

2.7.3 Alq₃

Since the first efficient low-voltage-driven organic light-emitting diodes (OLEDs) based on tris(8-hydroxyquinoline)aluminum (Alq₃) were reported by Tang and VanSlyke, Alq₃ has become a prototypical electron transport and emitting material for OLED devices because of its excellent stability and electroluminescence properties. A facile self-assembly route has been developed in this lab to for the first time synthesize Alq₃ nanorods with regular hexagonal shape and good crystallinity in solution. FTIR, Raman spectral, and XRD experiments reveal that the prepared nanorods have α-phase crystal structure. Selected area electron diffraction (SAED) and structural analysis show the nanorods grow along crystallographic c axis. The field-emission characteristics of the nanorods exhibit a very low turn-on field of ca. 3.1 Vμm^-1 and a high field-enhancement factor of ca. 1300. This result expands the potential application of Alq₃ in optical, electronic, and nanodevice field. Related research work has been published in the Chemical. Communication (2007, 3083-3085).

2.7.4 Fullerenes

C₆₀ and its derivates, as a new type of carbon materials with unique properties, are of tremendous interest in diverse areas. For the applications of C₆₀ material, one remaining challenge is to produce it with pre-designed and controllable structures within the sub-micrometer or nanometer scale. We developed a reliable and facile solvent-induced self assembly method to produce C₆₀ single-crystal 1D sub-micrometer rods and tubes with controllable size and morphologies. The length aspect ratio of the 1D materials are readily tuned by varying the concentration of C₆₀ in m-xylene, and their morphologies can be chosen from rod to tube by using different m-xylene/isopropanol volume ratio. A C₆₀ concentration profile controlled growth mechanism has been supposed explain the self-assembly process of C₆₀ 1D sub-micrometer structure. The present work shows that it is possible to produce C₆₀ rods or tubes simply by tuning the reaction conditions. It may also contribute to better understanding of chemistry of fullerenes in solutions. A part of the related research work has been published in the Journal of Physical Chemistry C (2007, 111, 10498-10502).

2.8 Syntheses, Purification and Characterizations of Unconventional Fullerenes

The geometries of pure-carbon fullerenes synthesized thus far follow exclusively the isolated-pentagon rule (IPR), which states that the pentagons in the most stable fullerenes are isolated from each other by hexagons. Due to enhanced steric strain (steric effect) and resonance destabilization pertaining to the pentalene-type 8-electron system (electronic effect), pure-carbon non-IPR fullerenes with abutted pentagons are always unstable and synthetically unattainable. However, it appears that non-IPR fullerenes can be stabilized by either endohedral inclusion of electron-donating metal atoms/clusters or exohedral derivatization, as exemplified by such non-IPR fullerene derivatives as the endofullerenes Sc₂@C₆₆, La₂@C₇₂, and Sc₃N@C₆₈ as well as the exohedral derivative C₅₀Cl₁₀.

We developed two methods to violate the IPR. First, We synthesized and isolated a metal carbide encapsulated metallofullerene Sc₂C₂@C₆₈, which shows the valence state (Sc³⁺)₂(C₂)^2-@C₆₈^4-. It was clearly revealed that endohedral clusters function as templates for the synthesis of different non-IPR C₆₈ cages. Second, we synthesized, isolated and characterized the a stable unconventional fullerene derivative C₆₄H₄ by introducing methane in the fullerene productions with the normal Kratschmer-Huffman method. We also applied various spectroscopic measurements such as mass spectrometry, ¹³C NMR, IR, UV-vis absorption spectrometry, etc. to characterize the structural and electronic properties of this molecule, revealing an unprecedented fullerene cage with a triplet of directly fused pentagons in the framework of C₆₄H₄. Four hydrogen atoms are added to the carbons at vertexes of fused pentagons to allow the bond angles at these sites close to the sp³ tetrahedral angle, which essentially release the sp² bond strains on the abutting-pentagon sites of C₆₄. Ab initio calculations were performed to explore the electronic property and simulate the ¹³C NMR and IR spectra of this fulleride, which reproduced well the experimental results and confirmed the structural assignment of the C₆₄H₄.

2.9 Chemical Reactions of Endohedral Fullerenes

Endohedral metallofullerenes are currently becoming the most studied classes of compounds within the field of fullerenes due to their unique structures and novel properties. Ever since macroscopic quantities of the fantastic material could be obtained, numerous research works have been conducted on the synthesis, isolation, characterization and exohedral modifications of endohedral metallofullerenes. However, their low product yields have seriously limited the research on the chemical properties of endohedral metallofullerenes. As of today, little systematic research has been reported on the fundamental question about the effect that the encaged clusters have on the electronic structures and chemical properties of endohedral metallofullerenes. To address this question, we carried out macroscopic synthesis and isolation of a series of trimetal nitride endohedral (TNT) fullerenes with similar carbon cage and different encaged clusters and further explored the technique of synthesis and isolation of the mixed metal TNT fullerenes. Based on the fullerenes obtained, we carried comparative theoretical and experimental studies focus on the dependence of electronic structures and chemical properties on the change of endohedral clusters.

2.9.1 Chemical Reactions of Sc_xY_3-xN@C₈₀  (x = 0-3)

Comparative experimental and theoretical studies of Sc_xY_3-xN@C₈₀  (x = 0-3) fullerenes are reported for the first time. The electronic structures of Sc₃N@C₈₀, Sc₂YN@C₈₀, Y₂ScN@C₈₀ and Y₃N@C₈₀ were analyzed by studying HPLC retention behaviours, laser desorption time-of-flight (LD-TOF) mass spectrometry, differential pulse voltammetry, Fourier transform infrared (FTIR) spectroscopy, and visible-near infrared (vis-NIR) absorption spectroscopy. In addition, cycloaddition reactions of N-enthylazomethine ylide with Sc_xY_3-xN@C₈₀(x = 0-3) were carried under similar conditions and the monoadducts were characterized by HPLC, LD-TOF MS, ¹H and ¹³C NMR spectrometry. The results show that Sc₃N@C₈₀ and Sc₂YN@C₈₀ have nearly same electronic structures and frontier orbitals, and ScY₂N@C₈₀ and Y₃N@C₈₀ do. A critical transformation on the molecular frontier orbitals occurs at the point from Sc₂YN@C₈₀ to ScY₂N@C_80. Moreover, the cycloaddition reactions of Sc_xY_3-xN@C₈₀ (x = 0-3) confirm the critical change of regioselectivity between Sc₂YN@C₈₀ and ScY₂N@C₈₀. These findings show that the size of the endohedral moiety plays an important role in affecting the electronic properties and chemical properties of endohedral fullerenes, even though they have like geometric structures.

2.9.2 Chemical Reactions of Sc_xGd_3-xN@C₈₀  (x = 0-3)

      The combined experimental and theoretical investigations are carried out on the regiochemistry of a series of TNT endohedral fullerenes Sc_xGd_3-xN@C₈₀ (x = 0-3) in 1,3-dipolar cycloadditions, which demonstrates that the [6,6]-pyrrolidino-adducts of Gd₃N@C₈₀ is the major product with minor [5,6]-pyrrolidino-adducts, a regioselectivity that is drastically different from that of Y₃N@C₈₀ and Sc_xGd_3-xN@C₈₀ (x = 1-3). The combined experimental and theoretical investigation clearly demonstrates that the regioselectivity of the TNT-based endohedral fullerenes Sc_xGd_3-xN@C₈₀ (x = 0-3) in the exohedral cycloadditions depends remarkably on the size of the encaged cluster, i.e., [5,6]-regioisomers being major products in the Sc_xGd_3-xN@C₈₀ (x = 1-3) cases and [6,6]-regioisomers being major products for the largest Gd₃N@C₈₀.

2.9.3  Metallofullerene-Based MRI Contrast Agents

Endohedral metallofullerenes have attracted broad attention because of their unique structures, novel properties and wide potential applications in chemistry, physics, material science and medicine. With a view to potential application as high-efficient and low-toxic MRI contrast agents of next generation, we synthesized several kinds of MRI contrast agents based on Gd@C₈₂ and explored their relaxivity of water proton and aggregate behavior. Water-soluble derivatives of Gd@C₈₂, Gd@C₈₂O₈(OH)₃₀ and Gd@C₈₂O₆(OH)₁₆ (NHCH₂CH₂COOH)₈, were synthesized by one-step procedure with high yield. The proton relaxivity, R₁ (the gauge of contrast agent efficiency, and the paramagnetic longitudinal relaxation rate enhancement of water protons, referred to 1 mM concentration) was measured together with in vitro MRI phantom studies by the T₁-weighted spin-echo method. The obtained R₁ is 58.2 mM^-1s^-1 and 9.1 mM^-1s^-1, respectively, which is much higher than that of the clinical Gd-DTPA (3.2 mM^-1s^-1) under the same conditions, indicating the high efficiency of the molecules as MRI contrast agent.

3. Biomolecular interacation and reaction study at the single molecule level

3.1 DNA/protein interaction study

     Based on our former DNA/protein interaction study by AFM force measurement, we further improved and established methods of single molecule force spectroscopy and dynamic force spectroscopy, together with fluorescence spectroscopy, for DNA/protein interaction study at the single-molecule level. 

3.1.1 Study of the transcription factor/DNA element interaction

Specific interactions between transcription factors and DNA responsive elements are of fundamental importance in understanding how genetic regulatory proteins control gene transcription. With single molecule force microscopy, we have measured the interaction forces for a serious of plant transcription factor/DNA element, including those between TINY, OsDEBF,THS1 and DRE, ERE. The results further confirm the applicability and high sensitivity of AFM measurements in transcription factor-DNA interaction study. More interesting, it was found that while the 14th amino acid mutation of TINY in its DNA binding domain resulted in its lost of binding affinity with DRE,  its 19th amino acid mutation caused the decrease of the binding force but the binding probability was the same as the wild type TINY. The reduced binding force was correlated with the reduced activity of TINY regulated reporter gene in the yeast one-hybrid experiment. AFM is expected to be a simple, quick, sensitive and reliable method that offers valuable information for the characterization of transcription factors （Polymer 2006，47 (7): 2533-2538）

3.1.2  Study of DNA Binding and Bending by EcoRI DNA Methyltransferase

We have applied fluorescence anisotropy and fluorescence resonance energy transfer (FRET) techniques to study the interaction between EcoRI DNA methyltransferase (M.EcoRI), and its target DNA in solution. The binding affinity of M.EcoRI. to two dsDNA fragments (20bp and 38bp) was studied with fluorescence anisotropy. Their binding constants at different temperatures from 20 to 40 ℃ were obtained and the thermodynamic parameters of binding were derived. The results showed the binding of M.EcoRI to DNA was primarily entropy driven. By labeling the 5` ends of the 20bp dsDNA with two fluorescent dyes, we calculated the end-to-end distance of the dsDNA was changed from 72.4 to 63.4 Å, and the DNA bending angle was estimated as 57.8°. We will further investigate the bending of DNA at the single molecule level (J. Phy. Chem. B, 2006,110, 19647)。

3.2 Single molecule study in living cells

Real-time monitoring of single biomolecules in living cells is a major goal in single molecule study. We have applied single molecule fluorescence microscopy and single molecule force microscopy to the visualization and characterization of important membrane proteins in living cells for cell signaling study.

3.2.1  Single molecule imaging and tracking of growth factor receptors

With our home-build objective-type total internal reflection fluorescence microscopy (TRFM), we have established the method of imaging single GFP coupled membrane proteins and tracking their lateral diffusion. We have applied the techniques to study two typical types of growth factor receptor,  HER2/HER3 tyrosine kinases and TGF-b receptor serine/threonine kinases, and obtained the new results on the their activation and signal transduction. For example, we have investigated the lateral diffusion of transforming growth factor b (TGF-b) type I receptor (TbRI) in living cells. It is found that when co-expressed with TGF-b type II receptor (TbRII), the mobility of TbRI decreased significantly after TGF-b1 stimulation. However, in the cells that had been depleted of cholesterol with Nystatin or methyl-b-cyclodextrin, the diffusion rate of TbRI was not changed by TGF-b1 treatment. Our observations suggest that membrane lipid rafts provide an environment that facilitates the association of TbRI and TbRII for cell signaling（Biochem Biophys Res Commun，2007，292，31-40）。

3.2.2 Single molecule force study of ligand-receptor binding .

We have carried out a single molecular study of Mac-1/ ICAM-1 interaction force in living cells by atomic force microscopy (AFM). The interaction between Mac-1 and ICAM-1, which is controlled tightly by the ligand-binding activity of Mac-1, is central to the regulation of neutrophil adhesion in host defense. Several “inside-out” signals and extracellular metal ions or antibodies have been found to activate Mac-1, resulting in an increased adhesiveness of Mac-1 to its ligands. However, the molecular basis for Mac-1 activation is not well understood yet. Our results showed that the binding probability and adhesion force of Mac-1 with ICAM-1 increased upon Mac-1 activation. Moreover, by comparing the dynamic force spectra of different Mac-1 mutants, we expected that Mac-1 activation is governed by the downward movement of its a7 helix (Exp. Cell Res. 2007, in press).

     We have also applied the single molecule force spectroscopy and single molecule dynamic force spectroscopy to study the interaction between TGF-b and its receptors in living cells. It is revealed that the recruitment of TbRI to TGF-b1/TbRII complex led to a stronger binding of TGF-b1 to the singling complex, which may facilitate the signal transduction process.

4. Applcations of Nanomaterials in Sensors

4.1   Applications of metal oxides in sensor

Metal oxides are usually N or P type semiconductors, which enable them to be sensing materials in semiconductor sensor. The hierarchical structured metal oxides show several advantages over normal metal oxides: the primary building block of our materials are nanoparticle, nanowires or nanofilms, with desired quantum size effects for possible high sensitivity and selectivity. In addition, hierarchical structure brings high surface area and large adsorption ability, and the diffusion of species on the materials is facile, which is desired for fast response and recovery of the sensor. Micron sized overall structure are also robust, which is ideal for long sensor life. Signals from iron oxide in our work has much faster response and recover rate than that of normal iron oxide.（Micropor. Mesopor. Mater. 2007, 100, 233; J. Phy. Chem. B. 2006, 110, 15858）。

4.2  Dynamic adsorption/desorption method for gas identification

By varying the working temperature of a sensor, thus promoting the adsorption and desorption of gases on the sensing materials, we recorded the signal change along the temperature change. Subsequent data processing generates a dynamic adsorption/desorption curve of each gas. The shape of each curve is depended on the chemical structure of the gas molecule, like spectroscopic spectrum of a molecule, and can be used to identify the molecule. Base on this, we developed a single sensor based electronic nose system. This method uses kinetic adsorption and desorption process to identify gases, so that only one sensor is needed. In comparison, a traditional electron nose, which rely on stead state signal at constant temperature, requires many sensors to form a array. （Sensor Actuator B Chem. 2007, 123454）.

4.3 Nanobiosensor for protein detection.

We have developed the new nanobiosenor for quick and high-throughput protein detection based on conducting polymer and aptamers, the novel protein probes. The has the advantageous of simpler synthesis, more stable and easy of making arrays for multi-protein detection comparing to the antibody modified semiconducting inorganic nanowire sensors. We have developed the method of electrochemical polymerization of aptamer-grafted pyrrole and the formation of nanowire network between the junction of two microelectrodes. The sensors showed high sensitivity and selectivity as demonstrated by thrombin detection.

（2）. Group’s potential to be internationally competitive in related research fields has been significantly enhanced

The Creative Research Groups for molecular nanostructure and single molecular physical chemistry is composed of the researcher from the Laboratory for molecular nanostructure and nanotechnology, a CAS key lab. Prior to the formation of this group in 2001, the research field of the lab was limited to molecule self-assembly on substrates and biological single molecules. With financial supports from NSFC’s Science Fund for Creative Research Groups, and led by professor Chun-Li Bai, the group pursuit a integrated scientific goal, which includes the upgrading of the lab, recruiting and development of researchers, expanding and adjusting the research fields. Since 2001, the research group has become an internationally recognized research group for its outstanding young researchers, broad and inter-disciplinary research fields and high level research works. The ability of the group to pursue a leading role is illustrated in the following sections:

2.1 Broad and inter-disciplinary research field

Nanotechnology is a multi-disciplinary field, involving chemistry, physics, biology, material sciences, devices and electronics. With the supports from this fund, in addition to surface physical chemistry, chemistry and biological chemistry, we expand our research field to material sciences, analytical chemistry and nano devices. Especially since 2005, after the first phase (2002-2004) support from NSFC, the group was in good position in terms of recruiting, international collaboration and research experiences. We intensified our effects to broaden our research scope, adding nano materials and nano devices as our research focuses, by expanding the research fields of exiting researchers and by recruiting new researchers in these fields. During the recent years, the group has developed our own ability to produce samples for surface physical chemistry. The synthesis, characterization and application of nano materials has now become the leading research fields of this group, as shown in many research work at internationally recognized level.   

In summary, with support from NSFC fund, the research group focused on the scientific gola of the contruction and characterization of nano structures and single molecula physical chemistry. Research fields include physcial chemistry, biological chemistry, analytical chemistry, material chemistry and microelectronics, computational chemistry and inter-disciplinary sciences. The research group has grown into a versatile leading research group in related fields. The researchers in the group complement each other and collaborate with each other. A few examples include a sub-division by Professor Chun-Li Bai, Li-Jun Wan, Chun-Ru Wang and Wei-Guo Song is working on the synthesis, characterization and integration of micro-nano structured materials; a sub-division by professor Xiao-Hong Fang and Li-Jun Wan focus on biological single cell and single milecule’s behavior; a sub-division by professor Li-Jun Wan, Chun-Ru Wang and Wei-Guo Song is working on functiional nanomaterials’ contructions and applications; a sub-division by Li-Jun Wan, Chun-Ru Wang and Yu-Guo Guo is working on the procotype functional nano devices;  while another sub-division by Chun-Li Bai, Xiao-Hong Fang and Li-Jun Wan is working on developing new tools for studing the molecular nanostructures. These divsified research sub-divisions enable us to play a leading role in several research fronts.

2.2   Outstanding researchers

NSFC Science Fund for Creative Research Groups is basically a personal development fund, one aim of which is to help the progress of outstanding researchers to be competetive internationally. With the support of this fund, researchers in the group have exceled and the groups ability in research and potential to be a prominate research institution has increased substanitially. So far, the researchers of the group include Professor Chun-Li Bai, who is the academian of the CAS, member of the third world academy of sciences, and the foreign member of the US National Academy of Sciences. The group also has six researchers who has won the prestigious “National Science Fund for Distinguished Young Scholars”, Two researchers served as the Chief Scientists of the MOST 973 project or Nano Technology Project. Four researchers were awarded CAS “One Hundred Talents” Fund; and one researcher was awarded Institute of Chemistrys “Outstanding Young Researcher” fund. 

The chief scientist of the group, Professor Chun-Li Bai is an internationally prominent scientist. He is an academian of the CAS, member of the the Third World Academy of Sciences of, and a foreign member of the US National Academy of Sciences, and is widely regarded as the leader of China’s nanotechnology.

Another chief scientist of the group, professor Li-Jun Wan, is the director of the Institute of Chemistry as well as the director of the CAS Key Laboratory of the Molecular Nanostructures and Nanotechnology. He is also the junction professor at several major Universities in China, including Hong Kong City University, Dalian Scientist and Technology University. In recent years, Professor Wan has won several awards, including the First Award in Science and Technology by the City of Beijing; China-German BASF young scientist award; First and second award by the Chinese Analytical society. He has been the chief scientist of MOST 973 project and CAS major research project, as well as several NSFC’s research projects. He serves as the editor of international journal NANO and Chinese Journal Chinese Science (Chemistry), Associate editor in chief of Electronic Microscopy. In addition, he also serves on the advisory board of several major journals such as Account of Chemical Research, Angew. Chem. Int. Ed., Chemistry of Materials, J. Phys. Chem..

Professor Chen Wang is a senior scientist in this group. He is also the deputy director of the Chinese National Center for Nanoscience and technology. He is a junction professor at Beijing University, Jilin University and Huazhong Normal University. He has been a chief scientist for MOST 973 project. He was also awarded a first award by the Chinese Ministry of Education.

Other researchers of the group have also developed into outstanding scientists by the support from NSFC fund. Professor Chun-Ru Wang joined the group in Jan. 2002 when he was awarded CAS “One Hundred Talent” fund. At the same year, he was awarded the “National Science Fund for Distinguished Young Scholars”. In 2005, his work under CAS “One Hundred Talent” fund was rated as excellent. His work under National Science Fund for Distinguished Young Scholars was also rated as excellent in 2006. He becomes a recipient of special government allowance program in 2007.

Professor Xiao-Hong Fang was awarded CAS “One Hundred Talent” fund and joined the group in Dec. 2001. She won the “National Science Fund for Distinguished Young Scholars” in 2002. In 2005 and 2006 her work under these research award were also rated as excellent, respectively. In 2007, she becomes a chief scientist of a MOST 973 project. In addition, she has also won several other awards, including Chinese Chemical Society’s Outstanding Young Chemist award.

Professor Wei-Guo Song was awarded CAS “One Hundred Talent” fund and joined the group in July 2005 to boost our ability in nano material synthesis and application. He quickly fitted into the group and worked on the nano catalysis and related fields. He was awarded the “National Science Fund for Distinguished Young Scholars” in 2007.

Professor Yu-Guo Guo was a graduate student when the group was formed in 2002. He was a beneficiary of the NSFC support to our group’s effect to broad our research to nanomaterials. Under supervision by several researchers in the group, he graduated in 2004 and his dissertation was rated as excellent by CAS. After two years of oversea study, he joined the group in 2007 and was awarded Institute of Chemistry’s “Outstanding Young Scientist” fund.

2.3. Research Accomplishments

With NSFC Fund’s support, the group has made substantial progress in several research fields. In molecular nanostructure assembly, researchers led by Professor Chun-Li Bai, Li-Jun Wan and Chen Wang systematically studied the effects of the substrates, ligands, molecule structures on the construction of surface molecular nanostructures, and explored the effect of external stimuli including heat, light and magnetic field on molecular assembly. Related studies have won the First Science and Technology of the City of Beijing, the First Award of the Chinese Analytical Society, and the First Award in Science progress by the Ministry of Education. In nanomaterial research, the researchers systematically studied nano materials for energy, environmental protection, organic photoelectronics, sensor and carbon materials. These studies are of important scientific value, some of them also see potential application in industry.

The number of high quality papers also indicates the rapid progress of the group. Prior to 2002, the number of papers published on major journals such as JACS, Angew. CHem. Adv. Mater. is quite low by the group members. However, during the first three years (2002-2004) of the project, the number was 8, and during the recent years (2005-2007), the number has increased to 21. Some of the papers were chosen as cover paper or VIP paper by these journals

2.4 Comprehensive international collaboration

Scientific exchange is an important avenue for us to improve. With NSFC fund’s support, we put great effect to establish broad and long term collaborations with several international scholars, including professor Shui-Tong Li of the Hong Kong City University, Professor Xiao-Liang Xie from Harvard University, Wei-Hong Tan of the University of Florida, Professor Lai-Sheng Wang of the Washington University, Professor Shu-Guang Zhang of the MIT, and Professor Hong-Qi Xu of the Lund University. Through joint research projects, and student exchange, we made significant progresses. We also have regular collaborations with professor Guan-Hua Chen of Hong Kong University, Professor Dunsch of the Drexton Institute of Solid, Professor Shinohara of Nagoya University, Professor Itaya of the Tohoku University, and professor Osawa of the Hokudai University through joing project and periodic discussions. In addition, we established regular connection with other international recognized research institutions and scholars in US, Germany, British, France, Japan and Demark. etc.

We also established long term collaborations with more than 10 domestic research institutions. We have joint project with the Institute of Physics to study the theory of single molecule, and joint project with the Institute of Biological Physics, Shanghai Institute of Biological Chemistry, and Qinghua University to study the single molecule on membrane protein and interaction between DNA and protein. We also have collaboration with Xiamen University to study fullerene materials.

Through these comprehensive scientific collaborations, we not only established long term connections and enhanced mutual understandings with international as well as domestic researchers, but also keep us informed of the latest scientific progress in related field. As a result, the group’s overall research capacity has been significantly enhanced.

2.5 Improved management

We paid special attention to establish a regulation system that enables smooth running of the research labs. The chief scientists, Chun-Li Bai and Li-Jun Wan are in charge of the group. All researchers are involved in the discussions to plan research projects, while the chief scientists make the decisions on major projects and coordinate the research plan. For certain challenging projects, more resources are allocated to it, and this is the power of group work to take on these projects. For each project, there is a researcher in charging of it and reports to the chief scientists periodically. We also seek external evaluations by reporting our progress to international or domestic reviewers for their opinions and suggestions.

Young researchers, including assistants and graduate students do lab work for each project. They play key roles in our group. We put great effect in help young researchers to fulfill their career ambitions and encourage them to propose their plans for the projects they are working on. Twice a year the group holds award events to recognize those young researchers who have done creative research works. As a result, the group has become a major education center for highly qualified researcher in nanotechnology.