Paper TF-ThP24
Toward Reliable Production of Well-Structured, Self-Assembled Thin Films of Quantum Dots for Surface Coatings

Thursday, November 10, 2016, 6:00 pm, Room Hall D

The goal of this study is to deposit Langmuir films of quantum dots (QDs) as reliably well-structured, self-assembled, monolayer films. Such films will be increasingly important as pre-cursors to coat thin-film light-emitting devices, solar cells, transistors, and diode lasers where the uniformity of the film plays a key role in the consistency of its properties. The structure of the Langmuir films is imaged at macroscopic to microscopic scales using optical and Brewster angle microscopy. Image processing and analysis are done to characterize the patterns. Corresponding image analysis is also done on Langmuir-Schaefer (LS) films that have been templated from the Langmuir films, and comparisons are made to the film quality in the two cases. The topography and thickness of the LS films are subsequently measured by scanning probe microscopy. The structure of the Langmuir films is controlled to first order by the concentration and volume used during deposition. Common patterns seen include agglomerates, sheets, and streaks. The structure can be refined by adding an organic co-additive at different molar concentration ratios. Above a certain ratio, the QDs and co-additive show phase separation. Systematic characterization of the relationships between deposition parameters and film structure will bring the Langmuir deposition process from being just a laboratory-scale experiment to being a reliable production-level tool to produce well-structured, self-assembled thin films of QDs for surface coatings.