Complex Electron Transfer Pathway at a Microelectrode Captured by in Situ Nanospectroscopy

Abstract

In the quest for analytical tools which enable the characterization of materials at the nanoscale and under the condition of their operation (in situ, operando), the emerging tip-enhanced Raman spectroscopy (TERS) now enters the spotlight. We demonstrate in this work that a TERS tip can be functionalized and partially insulated to be used as a microelectrode enabling electrochemical substrate enhanced Raman sectroscopy (EC-SERS) at a single hotspot. This "SERS at a tip" experiment enables one to capture the electrochemical transformation of a molecular layer self-assembled on a tapered gold microelectrode. The proposed setup and protocol open new perspectives in the characterization and development of complex redox architectures for molecular devices.

Tunable SERS Platforms from Small Nanoparticle 3D Superlattices: A Comparison between Gold, Silver, and Copper

“…To emphasize the SERS performance of the C 12 SAu 5nm NP SLs, some of the dodecanethiol ligands were replaced by 4‐nitrothiophenol (4‐NTP; Figure b), a reference molecule in SERS studies . A sample covered with thick gold SLs was left in a solution of 4‐NTP (1 m m ) in ethanol for 20 h. Because ethanol is a poor solvent for gold NPs, it could not dissolve the gold SLs.…”

“…To emphasize the SERS performance of the C 12 SAu 5nm NP SLs, some of the dodecanethiol ligandsw erer eplaced by 4-nitrothiophenol( 4-NTP;F igure 10b), ar eference molecule in SERS studies. [38,39,44] As ample covered with thick goldS Ls was left in asolution of 4-NTP(1mm)inethanol for 20 h. Because ethanol is ap oor solvent for gold NPs, it could not dissolve the gold Figure 5. SERS spectra of dodecanethiolate ligands collected on individual gold NP SLs (C 12 SAu 5nm )with differentt hicknesses (black:6 3, red:1 16, green:2 29 nm) at three laser excitationwavelengths:a)l exc = 473 nm, laser power 13 mW, t aq = 5saveraged for nine points of the SLs, b) l exc = 532 nm, laserp ower 30 mW, t aq = 5saveraged for nine points of the SLs, c) l exc = 633 nm, laser power 70 mW, t aq = 300 s. The spectrah ave been shifted for clarity.…”

Le TERS, ou comment obtenir une signature chimique à l’échelle nanométrique

“…En électrochimie également, la pointe TERS pouvant être utilisée comme électrode de travail, le TERS permet de suivre des réactions d'oxydoréduction cycle par cycle et d'estimer précisément l'avancée de la réaction chimique. Cette nouvelle application ouvre ainsi la voie à l'utilisation du TERS dans le milieu de l'énergie et des batteries [5]. condition que les pointes utilisées pour les générer soient elles-mêmes reproductibles.…”

Long range self-organisations of small metallic nanocrystals for SERS detection of electrochemical reactions

“…To this respect, it was soon realized that the gain in sensitivity provided by Surface Enhanced Raman Spectroscopy (SERS) [5] would also benefit to electrochemistry. Nanoscale resolution is even nowadays accessible through Tip-Enhanced Raman Spectroscopy [7][8][9][10][11][12]. First SERS substrates were in fact roughened silver or gold electrodes [13,14], presenting randomly distributed "hot spots", i.e.…”