Molecular materials for photonics

Billions of years of evolution has produced a variety of functional components that enable life on Earth. The notable examples are chlorophylls that have a vital role in converting the energy of the Sun into chemical energy, and nucleobases that act as the building blocks in DNA/RNA, which store and convey the genetic information in living organisms. Thematically, this thesis is divided into two parts. The first part studies how the natural components, chlorophyll and uracil molecules, could be utilized in modern photonic applications. Publication I investigates the properties of supramolecular Zn chlorin-poly(4-vinylpyridine) assemblies that mimic the biological antenna structure. Moreover, this approach was used to create assemblies with macroscopically homogeneous pigment distribution. Publication II studies how FRET-mediated energy-transfer could be used to enhance the performance of the materials studied in Pub. I . In Publications III and IV, atomic/molecular layer deposition is established as a method to create fundamentally new three-dimensional sodium networked uracil assemblies with novel optical properties. The second part investigates how silver nanoparticle assemblies could be utilized in surface enhanced spectroscopic techniques. Generally, Publications V and VI investigate two economical nanofabrication methods to create large-scale plasmonic substrates. In Publication V , azopolymer lithography was utilized to create periodic plasmonic nanoparticle arrays for fluorescence enhancement. In Publication VI , a method utilizing cryogenic deep reactive ion etching with inductively coupled plasma was used to create a plasmonic substrate for surface enhanced Raman scattering applications. The results obtained in this thesis could pave the way for new biomimetic photonic materials and enable the utilization of economic and large-scale nanofabrication methods in creating new plasmonic materials. Especially, molecular layer deposition was established as a promising and scalable method to create materials with novel structural and optical properties.