| The work in this thesis includes a combination of four methods and applications for pyrite thin films produced via solution based processes.;Chapter 1 provides a brief introduction into earth abundant materials for photovoltaic applications. The issue of supply and price constraints is explored, and the motivation for pyrite thin films is explained. The fundamental properties of pyrite are provided along with a synopsis of previous pyrite device constructions and results.;Chapter 2 discusses the synthesis and characterization of phase-pure, single-crystalline, and clustered FeS2 nanocrystals synthesized in a one-pot "heat-up" synthesis. The NCs were then subjected to ligand removal with hydrazine to form polycrystalline pyrite thin films by sintering these layers of NCs at 450-600 °C under a sulfur atmosphere. The sintering behavior and precursor chemistry are explored.;Chapter 3 discusses the synthesis and characterization of phase-pure, single-crystalline, and well-dispersed colloidal FeS2 nanocrystals (NCs) synthesized in high yield by a simple hot-injection route in octadecylamine. The NCs were then subjected to partial ligand exchange with octadecylxanthate to yield stable pyrite NC inks. Polycrystalline pyrite thin films were fabricated by sintering layers of these NCs at 500−600 °C under a sulfur atmosphere.;Chapter 4 briefly covers the application of the FeS2 nanocrystals used in lithographically patterned microfluidic devices. Nanocrystals are solution deposited inside lithographically patterned channels on glass substrates. Subsequent ligand exchanges inside these channels allow for use of these patterned nanocrystal channels to develop microfluidic devices for DNA protein interaction footprinting.;Chapter 5 reports on solution-deposited, single-phase, large-grain, and uniform polycrystalline iron pyrite (FeS2) thin films fabricated on quartz and molybdenum-coated glass substrates from an iron (III) acetylacetonate molecular ink. The ink, prepared as a viscous solution of Fe(acac)3 and sulfur in pyridine, is spin coated and baked in air utilizing a layer by layer process to produce ∼300 nm thick, mixed-phase pyrite/marcasite thin films after annealing in H2S atmosphere. A second annealing step in sulfur vapor at 500-550°C yields phase-pure pyrite films with suitable morphology and mechanical properties for use in solar cells. The resulting pyrite films are characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), secondary ion mass spectrometry (SIMS), optical absorption spectroscopy, and variable-temperature Hall effect measurements. |
