Performance and long-term stability of surface-enhanced raman scattering substrates fabricated by dealloying of gold-silver nanostructures | |
| Author | Uraiwan Waiwijit |
| Call Number | AIT Diss. no.ISE-21-04 |
| Subject(s) | Surfaces (Technology) Raman spectroscopy Nanoparticles |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Nanotechnology, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. ISE-21-04 |
| Abstract | We describe a fabrication method of gold-silver (Au-Ag) nanorods with chemical dealloying process to improve surface-enhanced Raman scattering (SERS) performance and stability. The Au-Ag alloy nanorods are prepared by two different methods. In method one we first sputter Ag nanorods followed by a galvanic replacement of Ag with Au; and in the second method Au-Ag alloy nanorods are directly prepared by co- sputtering using glancing angle deposition method. Dealloying is then performed using acid or base etching in both the cases. The dealloying process of the Au-Ag film fabricated via galvanic replacement was unsuccessful and thus the SERS performance and stability is further carried out only with the Ag-Au nanorods prepared by glancing angle deposition method. For this second method, the SERS sensitivity of the Au-Ag nanorods was improved to 10-9 M for 4-mercaptobenzoic acid (4-MBA) used as Raman probe, compared to the pure Ag substrates, with similar shelf-life. For co-sputtering, the optimum condition of Au-Ag dealloyed substrate is achieved after immersing the as- deposited Au-Ag film in 30%NH40H: 30%H202: methanol for 40 s. Due to its surface roughness, this substrate exhibits an enhancement factor of 1.5 x 1 06. Long-term stability of the dealloyed substrates was observed over a month and found superior to the alloyed and Ag substrates. In addition, the dealloyed substrates are used for the detection of urinary crystals and clearly demonstrated SERS spectra of 10-4 M synthetic urinary crystals solution composed of calcium oxalate monohydrate, calcium phosphate and uric . acid. For uric acid, the substrates showed a good performance with a linear range of 0- 10-5 M and detection limit of 1.27x 1 0-6 M, which is less than the normal range of uric acid in healthy human. The Au-Ag dealloyed SERS substrates prepared in this study showed potential for early diagnosis of uric acid-type kidney stone diseases. |
| Year | 2021 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. ISE-21-04 |
| Type | Dissertation |
| School | School of Engineering and Technology (SET) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Industrial Systems Engineering (ISE) |
| Chairperson(s) | Bora, Tanujjal;Noppadon Nuntawong (Co-Chairperson); |
| Examination Committee(s) | Hornyak, Gabriel Louis;Shipin, Oleg; |
| Scholarship Donor(s) | Royal Thai Government;Asian Institute of Technology Fellowship; |
| Degree | Thesis (Ph. D.) - Asian Institute of Technology, 2021 |