Resonant Infrared Matrix-Assisted Pulsed Laser Evaporation: Advancing Methodology and Elucidating Mechanisms for Precise Control of Film Morphology and Composition

The aim of this dissertation is to advance the understanding and methodology of resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE), with a focus on the surfactant chemistry in organic emulsions, the fine modulation of film composition, and the development of novel deposition strategies combining both emulsion-based and solution-based target chemistries. RIR-MAPLE is a special thin-film deposition technique that extends the capabilities of the traditional pulsed laser deposition process to deposit a wide range of materials, including sensitive organic polymers (emulsion-based targets) and emerging hybrid perovskite materials (solution-based targets). It utilizes a pulsed laser, typically in the infrared range, which resonates with the vibrational modes of the matrix solvent molecules in a frozen target that comprises the material of interest dissolved in a primary solvent. The energy absorbed by the matrix solvent results in its sublimation, and kinetic energy is transferred to the solute (the material to be deposited), leading to solute ejection from the target without damaging sensitive organic materials. Although extensive research has previously been conducted to decipher the complexities of the RIR-MAPLE deposition process, several issues remain unresolved, and the full potential of this innovative technique has yet to be harnessed. This study addresses and investigates pivotal challenges inherent to RIR-MAPLE, paving the way for its application in a broader spectrum of future technological advancements.First, the deposition of organic material and its corresponding emulsion chemistry, specifically surfactant usage, was studied to determine predictive correlations with emulsified particle morphology and thin film properties. Consequently, the impact of surfactant choice on micelle density and the non-bonded interaction amongst disparate components was first documented and substantiated by the demonstration of blue organic light-emitting diodes (OLEDs). Second, an investigation was conducted to understand mechanisms for achieving fine control of composition when two organic materials are blended in a single film. An OLED exhibiting broadband emission due to two different polymer constituents was fabricated to demonstrate the precise control achievable over blended compositions. Consequently, it was discerned that the two organic materials remained contained within their respective emulsified particles and sequentially deposited atop one another without influencing the preceding deposited material. Third, the versatility of RIR-MAPLE was investigated by depositing films using solution-based and emulsion-based targets demonstrated by hybrid organic-inorganic perovskite (HOIP)-organic macromolecule nanocomposite films. A general approach for depositing such mixed nanocomposites was developed for RIR-MAPLE for the first time, subsequently unveiling the interactions between the organic macromolecule and the hybrid perovskite and achieving a fundamentally different compositional range and film morphology compared to other nanocomposite approaches.