Ordered plasmonic nanostructures are currently the subject of numerous scientific studies, due to their potential applications, from optical communications to chemical analyses and biomedicine. This thesis is focused on a special type of periodically ordered two-dimensional (2D) metallo-dielectric structure, noble metal films over microsphere arrays: from their fabrication and characterization, to spectroscopic applications. Prepared structures exhibit remarkable optical properties (including an unusually high transmittance, resembling the extraordinary optical transmission phenomenon), resulting from the excitation of surface plasmons. It is demonstrated that these plasmo-photonic structures are very promising multifunctional active-substrates for Surface Enhanced Raman Scattering, Metal Enhanced Fluorescence, and Surface Plasmon Resonance Spectroscopy.
Chapter 1 is devoted to giving an overview of the interesting aspects related to the optical properties and applications of periodically structured metals and dielectrics. We also briefly describe some of the currently developed nanofabrication techniques. A few concepts, like the photonic band and surface plasmon are introduced, being useful for the discussions in the upcoming chapters. We pay a special attention to colloidal photonic crystal films and noble metal structures obtained by templating on two-dimensional colloidal crystals. Chapter 2 presents own experimental results concerning the preparation, characterization and lithographic applications of two-dimensional (2D) colloidal crystal films. Results of the optical properties investigations are presented in Chapter 3, and divided in two main categories: i) photonic properties of bare microsphere arrays, and ii) plasmonic properties of noble metal nanostructured films deposited over microsphere arrays. In Chapter 4 we explore the capabilities of noble metal coated microsphere arrays to improve the sensitivity of optical spectroscopic methods: Surface Enhanced Raman Scattering, Metal Enhanced Fluorescence, and Surface Plasmon Resonance Spectroscopy.
Inhaltsverzeichnis (Table of Contents)
- INTRODUCTION
- CHAPTER 1
- PERIODICALLY STRUCTURED METALS AND DIELECTRICS WITH ENHANCED OPTICAL PROPERTIES
- PHOTONIC MATERIALS
- Photonic band gap
- Applications of photonic crystals
- Photonic crystals fabrication methods
- Photonic materials based on colloidal crystals
- PLASMONIC MATERIALS
- Surface plasmons
- Localized surface plasmons (LSP)
- Surface plasmon polaritons (SPP)
- Surface plasmon-enhanced spectroscopy
- Applications of surface plasmons
- Fabrication of plasmonic nanostructures
- Plasmonic materials based on colloidal crystals
- REFERENCES
- CHAPTER 2
- PREPARATION OF 2D MICROSPHERE ARRAYS AND USE IN NANOLITHOGRAPHY
- INTRODUCTION
- PREPARATION OF 2D POLYSTYRENE MICROSPHERE ARRAYS
- Drop-coating
- Improving drop-coating by sonication
- Convective self-assembly
- MORPHOLOGICAL CHARACTERIZATION
- Microsphere arrays prepared by drop-coating
- Microsphere arrays prepared by ultrasound assisted self-assembly
- Microsphere arrays prepared via convective self-assembly
- LITHOGRAPHIC APPLICATIONS OF 2D MICROSPHERE ARRAYS
- Metal Nanostructures Obtained by Nanosphere Lithography
- Nanosphere Lithography with a colloidal mono-layer
- Nanosphere Lithography with a colloidal double-layer
- Polymer Nanostructured Surface by Combining Nanoimprint Lithography and Nanosphere Lithography
- Polymer surface with arrayed nano-bumps
- Polymer surface with arrayed nano-dimples
- CONCLUSIONS
- REFERENCES
- CHAPTER 3
- OPTICAL PROPERTIES OF FABRICATED ORDERED NANOSTRUCTURES
- INTRODUCTION
- METHODS AND INSTRUMENTATION
- PHOTONIC PROPERTIES OF 2D MICROSPHERE ARRAYS
- Transmission and reflectivity of colloidal monolayers
- FDTD simulations of transmission and reflectivity
- Angle-resolved transmission measurements
- Assessment of the layers number and stacking pattern by micro-spectroscopy
- PLASMONIC PROPERTIES OF METAL FILMS OVER MICROSPHERE ARRAYS
- Unusual optical transmission
- Dependence on the sphere diameter
- Angle-resolved transmission
- Reflectivity of metal coated microsphere arrays
- CONCLUSIONS
- REFERENCES
- CHAPTER 4
- METAL COATED MICROSPHERE ARRAYS AS SUBSTRATES FOR ENHANCED OPTICAL SPECTROSCOPIES
- METAL COATED MICROSPHERE ARRAYS AS SURFACE ENHANCED RAMAN SCATTERING SUBSTRATES
- INTRODUCTION
- EXPERIMENTAL
- RESULTS AND DISCUSSION
- SERS of Nanostructured Ag film
- Optimization of SERS efficiency
- Optimization by sphere diameter
- Optimization by metal film thickness
- Confocal Imaging of local SERS enhancements distribution
- Single-molecule SERS hot-spots
- FDTD simulations of EM fields distribution
- METAL COATED MICROSPHERE ARRAYS AS SUBSTRATES FOR FLUORESCENCE ENHANCEMENT
- INTRODUCTION
- EXPERIMENTAL
- RESULTS AND DISCUSSION
- PLASMONIC MOLECULAR SENSING WITH SILVER COATED MICROSPHERE ARRAYS
- CONCLUSIONS
- REFERENCES
- GENERAL CONCLUSIONS
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This doctoral thesis explores the potential of ordered plasmonic nanostructures, specifically noble metal films over microsphere arrays, for applications in optical spectroscopy and sensing. The research covers fabrication, characterization, and applications of these structures, focusing on their unique optical properties stemming from surface plasmon excitation.
- Fabrication and characterization of ordered plasmonic nanostructures
- Optical properties of fabricated structures, including unusual transmission phenomena
- Applications in enhanced optical spectroscopies, such as Surface Enhanced Raman Scattering (SERS) and fluorescence enhancement
- Development of plasmonic molecular sensing using these structures
- The potential of these structures as active substrates for various spectroscopic techniques
Zusammenfassung der Kapitel (Chapter Summaries)
Chapter 1 provides an overview of photonic and plasmonic materials, outlining their properties and applications. It specifically focuses on surface plasmons, detailing their types (localized and polariton), their use in enhanced spectroscopy, and fabrication methods for plasmonic nanostructures. Chapter 2 delves into the preparation of 2D microsphere arrays, outlining various techniques such as drop-coating, sonication, and convective self-assembly. It further discusses the morphological characterization of these arrays and their use in nanolithography for creating metal and polymer nanostructures.
Chapter 3 focuses on the optical properties of the fabricated ordered nanostructures, exploring their photonic and plasmonic characteristics. The chapter examines transmission and reflectivity of colloidal monolayers, analyzes FDTD simulations, and explores angle-resolved transmission measurements. It also examines the unusual optical transmission behavior observed in metal films over microsphere arrays, including its dependence on sphere diameter and angle-resolved transmission. Chapter 4 investigates the potential of metal coated microsphere arrays as substrates for enhanced optical spectroscopies. It explores their application in SERS, examining experimental methods, optimizing SERS efficiency, and performing confocal imaging of local SERS enhancements distribution. The chapter also explores the use of these arrays for fluorescence enhancement and plasmonic molecular sensing.
Schlüsselwörter (Keywords)
This doctoral thesis focuses on the development and application of ordered plasmonic nanostructures, particularly noble metal films over microsphere arrays. Key terms include: surface plasmons, photonic materials, plasmonic materials, nanolithography, SERS, fluorescence enhancement, optical spectroscopy, and sensing.
- Quote paper
- Cosmin Farcau (Author), 2008, Ordered Plasmonic Nanostructures: from Fabrication to Relevant Applications in Optical Spectroscopy and Sensing, Munich, GRIN Verlag, https://www.hausarbeiten.de/document/293519
