Površinski pojačano Ramanovo raspršenje odabranih organskih boja na nanočesticama srebra I zlata

master's thesis

• Title (english): Surface-enhanced Raman scattering of selected organic dyes on silver and gold nanoparticles
• Author: Izabela Đurasović
• Mentor: Adriana Kenđel (mentor)
• Committee member: Adriana Kenđel (predsjednik povjerenstva)
• Committee member: Biserka Prugovečki (član povjerenstva)
• Committee member: Ivana Biljan (član povjerenstva)
• Committee member: Snežana Miljanić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2021-09-29, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Učinkovitost površinski pojačanog Ramanova raspršenja (SERS) nanočestica srebra i zlata
dispergiranih u svježe pripravljenim i koncentriranim koloidima te imobiliziranih na staklu
tretiranom s fluorovodičnom kiselinom i staklenom filter-papiru istraživana je pomoću metilenskog
modrila (MetB) i rodamina B (RB) pri pobudama 532 i 785 nm. Koncentrirane koloidne suspenzije
jače pojačavaju raspršenje zračenja boja u odnosu na svježe pripravljene koloide. U koncentriranom
koloidu zlata pri pobudi 785 nm opažene spektralne promjene upućuju na drugačiju orijentaciju
molekula MetB na površini zlata, u odnosu na koloid srebra. Atom sumpora iz fenotiazinskog
sustava boje tvori kemijsku vezu sa zlatom, dok su u koloidu srebra molekule MetB vezane na
supstrat preko atoma dušika fenotiazina. Kod svih korištenih supstrata pobuda pri 785 nm rezultira
intenzivnim vrpcama MetB i RB, dok pobuda pri 532 nm daje vrpce slabijeg intenziteta za MetB,
a vrpce RB zasjenjuje široka vrpca fluorescencije. U odnosu na koloidne suspenzije, nanočestice
srebra i zlata imobilizirane na čvrstim podlogama nisu se pokazale reproducibilnim supstratima
zbog neravnomjerne raspodjele nanočestica metala na površini supstrata.

Abstract (english)

Efficiency of surface-enhanced Raman scattering (SERS) of silver and gold nanoparticles dispersed
in freshly prepared and concentrated colloids, and immobilized on hydrofluoric acid-treated glass
and glass-fiber filter paper was investigated using methylene blue (MetB) and rhodamine B (RB)
at excitation of 532 and 785 nm. Concentrated colloidal suspensions intensified the scattering of
dye radiation, compared to freshly prepared colloids. In the concentrated gold colloid at 785 nm,
observed spectral changes indicated a different orientation of MetB molecules on metal surface,
compared to the silver colloid. The sulfur atom from phenothiazine created a chemical bond with
gold, while MetB molecules in the silver colloid were bonded to the substrate via phenothiazine
nitrogen atom. For all used substrates, the excitation at 785 nm resulted in intense MetB and RB
bands, while excitation at 532 nm yielded lower-intensity bands for MetB, and a wide fluorescence
band that overlapped RB bands. Metal colloidal suspensions were more reproducible substrates
than the solid substrates, due to the uneven distribution of nanoparticles on the solid substrates.

• Keywords: metilensko modrilo; nanočestice; rodamin B; SERS; srebro; zlato
• Keywords (english): gold; methylene blue; nanoparticles; rhodamine B; SERS; silver
• Language: croatian
• URN:NBN: urn:nbn:hr:217:548698
• 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: 2023-09-29
• Created on: 2021-10-18 10:28:12