TY - JOUR
T1 - Local feedback mode of scanning electrochemical microscopy for electrochemical characterization of one-dimensional nanostructure
T2 - Theory and experiment with nanoband electrode as model substrate
AU - Xiong, Hui
AU - Gross, Derrick A.
AU - Guo, Jidong
AU - Amemiya, Shigeru
PY - 2006/3/15
Y1 - 2006/3/15
N2 - Local feedback mode is introduced as a novel operation mode of scanning electrochemical microscopy (SECM) for electrochemical characterization of a single one-dimensional (ID) nanostructure, for example, a wire, rod, band, and tube with 1-100-nm width and micrometer to centimeter length. To demonstrate the principle, SECM feedback effects under diffusion limitation were studied theoretically and experimentally with a disk probe brought near a semi-infinitely long band electrode as a geometrical model for a conductive ID nanostructure. As the band becomes narrower than the disk diameter, the feedback mechanism for tip current enhancement is predicted to change from standard positive feedback mode, to positive local feedback mode, and then to negative local feedback mode. The negative local feedback effect is the only feedback effect that allows observation of a 1D nanostructure without serious limitations due to small lateral dimension, available tip size, or finite electron-transfer rate. In line-scan and approach-curve experiments, an unbiased Pt band electrode with 100-nm width and 2.6-cm length was detectable in negative local feedback mode, even using a 25-μm-diameter disk Pt electrode. Using a 2-μm-diameter probe, both well-defined and defected sites were observed in SECM imaging on the basis of local electrochemical activity of the nanoband electrode. Non-contact and spatially resolved measurement is an advantage of this novel SECM approach over standard electrochemical approaches using electrodes based on ID nanostructure.
AB - Local feedback mode is introduced as a novel operation mode of scanning electrochemical microscopy (SECM) for electrochemical characterization of a single one-dimensional (ID) nanostructure, for example, a wire, rod, band, and tube with 1-100-nm width and micrometer to centimeter length. To demonstrate the principle, SECM feedback effects under diffusion limitation were studied theoretically and experimentally with a disk probe brought near a semi-infinitely long band electrode as a geometrical model for a conductive ID nanostructure. As the band becomes narrower than the disk diameter, the feedback mechanism for tip current enhancement is predicted to change from standard positive feedback mode, to positive local feedback mode, and then to negative local feedback mode. The negative local feedback effect is the only feedback effect that allows observation of a 1D nanostructure without serious limitations due to small lateral dimension, available tip size, or finite electron-transfer rate. In line-scan and approach-curve experiments, an unbiased Pt band electrode with 100-nm width and 2.6-cm length was detectable in negative local feedback mode, even using a 25-μm-diameter disk Pt electrode. Using a 2-μm-diameter probe, both well-defined and defected sites were observed in SECM imaging on the basis of local electrochemical activity of the nanoband electrode. Non-contact and spatially resolved measurement is an advantage of this novel SECM approach over standard electrochemical approaches using electrodes based on ID nanostructure.
UR - http://www.scopus.com/inward/record.url?scp=33645238048&partnerID=8YFLogxK
U2 - 10.1021/ac051731q
DO - 10.1021/ac051731q
M3 - Article
AN - SCOPUS:33645238048
SN - 0003-2700
VL - 78
SP - 1946
EP - 1957
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 6
ER -