Površinski pojačano Ramanovo raspršenje na nanočesticama srebra u koloidnoj suspenziji i na čvrstoj podlozi

master's thesis

• Title (english): Surface-enhanced Raman scattering on silver nanoparticles in colloidal suspension and on a solid support
• Author: Helena Banović
• Mentor: Snežana Miljanić (mentor)
• Committee member: Snežana Miljanić (predsjednik povjerenstva)
• Committee member: Željka Soldin (član povjerenstva)
• Committee member: Ines Primožič (član povjerenstva)
• Committee member: Adriana Kenđel (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2020-12-16, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Istražena je SERS učinkovitost nanočestica srebra dispergiranih u koloidnim suspenzijama: svježe pripravljenoj, koncentriranoj i agregiranoj, te imobiliziranih na čvrstim podlogama: staklenom filter-papiru, staklu tretiranom s fluorovodičnom kiselinom i staklu silaniziranom s (3-aminopropil)trimetoskisilanom. Nanočestice srebra pripravljene su redukcijom srebrova(I) nitrata s trinatrijevim citratom te su nosile negativan naboj citratnih iona na površini. Rodamin 6G i fluorescein korišteni su kao modelne molekule pozitivnog i negativnog naboja. Zahvaljujući elektrostatskim privlačnim interakcijama pojačano Ramanovo raspršenje opaženo je za rodamin 6G sa svim istraživanim SERS supstratima, posebice u agregiranoj suspenziji srebra (EF = 5,68×106). Ramanovo raspršenje fluoresceina pojačano je samo na nanočesticama srebra imobiliziranim na staklu, i to najviše na nakupinama nanočestica u obliku prstena kave (EF = 8,23×103). Koloidne suspenzije srebra reproducibilniji su SERS supstrati od čvrstih SERS supstrata, što je posljedica nejednolike raspodjele nanočestica na čvrstim podlogama i otežanog fokusiranja zrake na uzorak prilikom snimanja spektra.

Abstract (english)

The SERS efficiency of silver nanoparticles dispersed in colloidal suspensions: freshly prepared, concentrated and aggregated, and immobilized on solid substrates: glass filter paper, hydrofluoric acid-treated glass and glass silanized with (3-aminopropyl)trimethoxysilane was investigated. Silver nanoparticles were prepared by reduction of silver(I) nitrate with trisodium citrate and carried a negative charge of citrate ions on the surface. Rhodamine 6G and fluorescein were used as model molecules of positive and negative charge. Owing to electrostatic attractive interactions, the enhanced Raman scattering was observed for rhodamine 6G with all investigated SERS substrates, especially in the aggregated silver suspension (EF = 5.68×106). The Raman scattering of fluorescein was enhanced only onsilver nanoparticles immobilized on glass, at most on the coffee ring-shaped aggregates (EF = 8.23×103). The silver colloidal suspensions were more reproducible SERS substrates than the solid SERS substrates, due to the uneven distribution of nanoparticles on the solid substrates and the difficulty of focusing the laser beam on the sample when recording the spectrum.

• Keywords: fluorescein; koloid; Ramanovo raspršenje; rodamin 6G; SERS; srebro; staklo
• Keywords (english): colloid; fluorescein; glass; Raman scattering; rhodamine 6G; SERS; silver
• Language: croatian
• URN:NBN: urn:nbn:hr:217:496169
• 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: 2021-12-16
• Created on: 2021-02-16 13:21:02