Pojačanje Ramanovog raspršenja na nanočesticama srebra i zlata veličine 20 nm

master's thesis

• Title (english): Enhancement of Raman scattering on 20 nm silver and gold nanoparticles
• Author: Antonija Kapusta
• Mentor: Snežana Miljanić (mentor)
• Committee member: Snežana Miljanić (predsjednik povjerenstva)
• Committee member: Željka Soldin (član povjerenstva)
• Committee member: Đani Škalamera (član povjerenstva)
• Committee member: Adriana Kenđel (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2022-02-25, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Istražena je SERS učinkovitost koloidnih suspenzija nanočestica srebra i zlata dimenzija 20
nm, stabiliziranih slojem citratnih iona (NP_cit) i poli(vinilpirolidona) (NP_PVP) na površini.
Snimljeni su SERS spektri rodamina 6G, etidijeva bromida i tiofenskog derivata bistriarilborana pri tri valne duljine pobudnog zračenja 532, 785 i 1064 nm. Sve su molekule
pozitivno nabijene te se adsorbiraju na nanočestice metala uslijed elektrostatskih privlačnih
interakcija s negativno nabijenim citratnim ionima na površini metala. Primijećeno je,
međutim, da pristup površini metala sterički ometaju taninska kiselina (AgNP_cit i AuNP_cit)
i poli(vinil pirolidon) (AgNP_PVP i AuNP_PVP), sastojci dodani tijekom ili nakon priprave
nanočestica. SERS spektri najčešće su opaženi nakon pobude Vis zračenjem (532 nm), koje je
najbliže plazmonskoj frekvenciji nanočestica metala (α(AgNP) = 427 nm, α(AuNP) = 525
nm) i omogućava pre-rezonantne uvjete mjerenja nužne za pojačanje raspršenog zračenja.

Abstract (english)

SERS efficiency of colloidal suspensions of 20 nm silver and gold nanoparticles, stabilized by
a surface layer of citrate ions (NP_cit) and poly (vinyl pyrrolidone) (NP_PVP) was
investigated. SERS spectra of rhodamine 6G, ethidium bromide and thiophene derivative of
bis-triarylborane were acquired at three excitation wavelengths 532, 785 and 1064 nm. All
molecules are positively charged and adsorb on metal nanoparticles due to electrostatic
attractive interactions with negatively charged citrate ions on the metal surface. It has been
observed, however, that access to the metal surface was sterically hindered by tannic acid
(AgNP_cit and AuNP_cit) and poly (vinyl pyrrolidone) (AgNP_PVP and AuNP_PVP),
compounds added during or after nanoparticles preparation. The SERS spectra were mostly
observed after excitation by Vis radiation (532 nm), which was closest to the plasmon
frequency of metal nanoparticles (α(AgNP) = 427 nm, α(AuNP) = 525 nm) allowing preresonant measurement conditions necessary for the scattering enhancement.

• Keywords: etidijev bromid; nanočestice srebra; nanočestice zlata; rodamin 6G; SERS
• Keywords (english): ethidium bromide; gold nanoparticles; silver nanoparticles; rhodamine 6G; SERS
• Language: croatian
• URN:NBN: urn:nbn:hr:217:793168
• 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
• Created on: 2022-03-22 12:43:47