Finding a Sensitive Surface-Enhanced Raman Spectroscopic Thermometer at the Nanoscale by Examining the Functional Groups

Abstract

Temperature variation at the nanoscale is pivotal for the thermodynamics and kinetics of small entities. Surface-enhanced Raman spectroscopy (SERS) is a promising technique for monitoring temperature variations at the nanoscale. A key but ambiguous topic is methods to design a sensitive SERS thermometer. Here, we elucidate that the type of chemical bond of molecular probes and the surface chemical bonding effect are crucial for maximizing the sensitivity of the SERS thermometer, as illustrated by the variable-temperature SERS measurements and quantum chemistry calculations for the frequency–temperature functions of a series of molecules. The sensitivity of the frequency–temperature function follows the sequence of triple bond > double bond > single bond, which is available for both aliphatic and aromatic molecules. The surface chemical bonding effect between the SERS substrate and molecular probe substantially increases the sensitivity of the frequency–temperature function. These results provide universally available guidelines for the rational design of a sensitive SERS thermometer by examining the functional groups of molecular probes.

Rapid detection and quantification of paracetamol and its major metabolites using surface enhanced Raman scattering

“…24 One way to enhance the Raman signal significantly is to apply surface-enhanced Raman scattering (SERS). This enhancement requires the analyte to be in close contact with a roughened metal surface [25][26][27][28] such as gold/silver in colloidal suspensions and highly quantitative analysis has been readily reported. [29][30][31][32] We have conducted extensive research in order to optimise SERS substrates for the detection of traces of drugs in human samples, 33 both illicit and legal.…”

“…24 One way to enhance the Raman signal significantly is to apply surface-enhanced Raman scattering (SERS). This enhancement requires the analyte to be in close contact with a roughened metal surface 25–28 such as gold/silver in colloidal suspensions and highly quantitative analysis has been readily reported. 29–32…”

In Situ Spectroscopic Elucidation of the Electrochemical Potential Drop at Polyelectrolytes/Au Interfaces

“…Figure c displays the potential-dependent SERS spectra of PCTP on Au in QAPPT. The characteristic bands at 582, 1074, 1177, 1584, and 2228 cm –1 were assigned to the spectral features of the PCTP adsorbed on Au . When the potential shifted from +273 to −727 mV, the spectral features remained, and the frequencies of all the bands shifted slightly.…”

In Situ Spectroscopic Identification of the Electron-Transfer Intermediates of Photoelectrochemical Proton-Coupled Electron Transfer of Water Oxidation on Au

“…48 To evidence the role of a photothermal effect in our system, we performed a variable-temperature SERS measurement on the surface Au hydroxides, which were made through application of a potential of 1.73 V in 0.1 M HClO 4 on a Au foil. 49 With a low laser power density, the effect of the temperature variation in the surroundings can be found in the SERS spectrum. Because the increase in temperature may lead to dehydration of surface Au hydroxides, the oxidized Au foil was kept at a high temperature for 3 min, and the temperature-dependent SERS spectra were acquired at decreasing temperature (see the Supporting Information for the details about the photothermal effect in the measurement).…”

“…The photothermal effect of a laser has been used to perturb an electrochemical process on Pt. , The photothermal effect in a SERS measurement was also reported . To evidence the role of a photothermal effect in our system, we performed a variable-temperature SERS measurement on the surface Au hydroxides, which were made through application of a potential of 1.73 V in 0.1 M HClO 4 on a Au foil . With a low laser power density, the effect of the temperature variation in the surroundings can be found in the SERS spectrum.…”