Nanočestice srebra i zlata na silaniziranom staklu kao čvrsti supstrati u SERS spektroskopiji

master's thesis

• Title (english): Silver and gold nanoparticles on silanized glass as solid substrates in SERS spectroscopy
• Author: Anastazija Ratkajec
• Mentor: Adriana Kenđel (mentor)
• Committee member: Adriana Kenđel (predsjednik povjerenstva)
• Committee member: Željka Soldin (član povjerenstva)
• Committee member: Đani Škalamera (član povjerenstva)
• Committee member: Snežana Miljanić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2022-09-26, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Istražena je SERS učinkovitost nanočestica srebra i zlata imobiliziranih na staklu silaniziranom (3-
aminopropil)trimetoksisilanom, odnosno (3-merkaptopropil)trimetoksisilanom. Korištene
nanočestice srebra i zlata pripremljene su redukcijom srebrova(I) nitrata hidroksilaminhidrokloridom, odnosno tetraklorozlatne(III) kiseline trinatrijevim citratom te je nastalim koloidima
određena SERS aktivnost. Kao modelne molekule odabrani su metilensko modrilo (MetB) i 4-
aminotiofenol (PATF) čiji su koncentracijski ovisni SERS spektri snimljeni pri valnim duljinama
pobude 532 i 785 nm na svim priređenim SERS supstratima. U koloidu srebra, kod obje valne
duljine pobude, molekule MetB adsorbiraju se na metal središnjim fenotiazinskim sustavom,
vezujući se preko atoma dušika. Uočeno je da u koloidu srebra molekule PATF nakon pobude pri
532 nm katalitički dimeriziraju u 4,4'-dimerkaptoazobenzen, dok se kod pobude pri 785 nm uočava
smjesa monomera i dimera u spektru. Pri pobudi od 785 nm u koloidu zlata opažene su spektralne
promjene pri nižim koncentracijama MetB koje upućuju na promjenu orijentacije molekula na
površini i vezanje na površinu zlata preko atoma sumpora. U odnosu na koloidne suspenzije,
nanočestice srebra i zlata imobilizirane na silaiziranom staklu nisu se pokazale reproducibilnim
supstratima zbog neravnomjerne raspodjele nanočestica metala na površini stakla i samo otopine
najvećih koncentracija daju vrpce u SERS spektrima.

Abstract (english)

The SERS efficiency of silver and gold nanoparticles immobilized on glass silanized with (3-
aminopropyl)trimethoxysilane and (3-mercaptopropyl)trimethoxysilane was investigated.
Nanoparticles were prepared by reducing silver(I) nitrate with hydroxylamine hydrochloride, and
tetrachloroauric(III) acid with trisodium citrate, respectively. For the prepared colloids the SERS
activity was determined, as well. Methylene blue (MetB) and 4-aminothiophenol (PATF) were
used as model molecules, whose concentration-dependent SERS spectra were recorded at excitation
of 532 and 785 nm. In colloidal silver, MetB molecules were adsorbed on metal by the central
phenothiazine system, binding through the nitrogen atom. In silver colloid PATF molecules
catalytically dimerize into 4,4'-dimercaptoazobenzene after excitation at 532 nm, while spectra
obtained from 785 nm showed a mixture of monomers and dimers. Using the excitation of 785 nm
in the gold colloid, spectral changes were observed at lower concentrations of MetB, indicating
orientation changes on the surface and binding to the gold surface via sulphur atoms. Compared to
nanoparticles in colloidal suspensions, silver and gold nanoparticles immobilized on silanized glass
did not prove to be reproducible substrates due to the uneven distribution of metal nanoparticles on
the glass surface, therefore only solutions of the highest concentrations gave bands in SERS spectra.

• Keywords: metilensko modrilo; nanočestice; SERS; srebro; zlato; 4-aminotiofenol
• Keywords (english): gold; methylene blue; nanoparticles; SERS; silver; 4-aminothiophenol
• Language: croatian
• URN:NBN: urn:nbn:hr:217:154799
• Study programme: Title: Graduate university studies in chemistry; specializations in: Research programme; Course: Research programme; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra kemije (magistar/magistra kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2024-09-26
• Created on: 2022-11-03 15:18:16