Prof. Bin Ren’s group made a significant progress of high spatiotemporal resolution electrochemical Raman spectroscopy. They developed a transient electrochemical surface-enhanced Raman spectroscopy (TEC-SERS) to deal with the increasing demand of dynamic and high solution characterizations of complex electrochemical interfaces. The related result of the study was published in J. Am. Chem. Soc. as Transient Electrochemical Surface-Enhanced Raman Spectroscopy: A Millisecond Time-Resolved Study of an Electrochemical Redox Process (J. Am. Chem. Soc., DOI：10.1021/jacs.5b07197). Meanwhile, they were the first to develop the electrochemical tip-enhanced Raman spectroscopy (EC-TERS) in the world based on the high spatial resolution tip-enhanced Raman spectroscopy (TERS). The result was also published in J. Am. Chem. Soc. as Electrochemical Tip-enhanced Raman Spectroscopy (J. Am. Chem. Soc., DOI: 10.1021/jacs.5b08143).

It’s always a challenging task of electrochemistry to acquire a fingerprint spectrogram of an electrochemical interface in real time under the condition of changing potential. They enhanced detection sensitivity and time resolution by developing a synchronized EMCCD-potentiostat, enhanced signal to noise ratio (SNR) of the data with a method of chemometrics and then they realized a SERS detection totally synchronized with electrochemical detection. They also studied the redox reaction of molecules on the surface of electrodes with a resolution shorter than the time the double layer charged on the surface of the electrode and found the dynamic information which is not possible for conventional steady state SERS methods to discriminate. This technology is capable for both reversible and irreversible electrochemical processes. Ph.D student Cheng Zong and M.S student Chan-Juan Chen of Prof. Bin Ren’s group are joint first authors. Prof. De-Yin Wu and Ph.D student Meng Zhang offered a significant theoretical support for the analysis of spectrograms.

URL link for article: http://pubs.acs.org/doi/abs/10.1021/jacs.5b07197

In order to characterize electrochemical interfaces at a nanoscale, they ingeniously designed the electrochemical in situ TERS electrolytic cell and redesigned the optics system of TERS so that they can use a mode of signals from horizontal excitation and collection to solve key technical problems such as the optical path distortion caused by heterogeneous aqueous layer. They first realized the EC-TERS technology in the world and applied to the study of the self-assembled monomolecular layer on the Au(III) surface, so they can get imperceptible changes of interfacial structures of electrode sensitively. The high spatial resolution and sensitivity provided by this technology will offer a significant tool to the study of heterogeneous electrochemical interfaces at a nanoscale. This work paid unremitting endeavors of several generations of graduates of this group. The experiments were finished by Ph.D student Zhi-Cong Zeng, Sheng-Chao Huang and so on. Prof. De-Yin Wu provided important support of spectroscopic data by theoretical calculations. Prof. Zhi-Lin Yang from the department of physics together with his M.S student Ling-Yan Meng provided the theoretical calculation of the electromagnetic field in aqueous solution.

URL link for article: http://pubs.acs.org/doi/abs/10.1021/jacs.5b08143

The group is committed to the development of methodology of Raman spectroscopy in a long-term. Besides the progress of electrochemical enhanced Raman spectroscopy mentioned above, the group also achieved series of progresses in other fields of Raman spectroscopy methodology: Aimed at the problem of the electrochemical activity of graphene, preparing the surfaces with different defect density on the same piece of graphene in control, they combined the technologies of electrochemical Raman and electrochemical microscope to gain the correlation between electrochemical activity and defect density reliably in the exactly same conditions of experiments (J. Am. Chem. Soc., 2014, 136,16609–16617); Aimed at the bottleneck problem of quantitative analysis with SERS, they realized the quantitative analysis in high concentration with SERS by using a SERS signal of the inner molecules of nucleus-molecule-core-shell nanostructure as an internal standard one to correct the fluctuation of the external signals undetermined (Angew. Chem. Int. Ed., 2015, 54, 7308 –7312); Aimed at the problem of bad reproducibility and low sensitivity of bioanalysis using SERS, they developed a method modifying nanoparticles with iodine and then realized direct detection of surface-enhancement Raman spectrum of label-free DNAs and proteins (J. Am. Chem. Soc., 2015, 137, 5149−5154; Anal. Chem., 2014, 86, 2238-2245).

They have written the concept article at Small’s invitation with their progresses in those fields (Small, 2015, 11, 3395–3406).