Effects of Solvent Vapor Annealing, Polarized Light, and CO2 gases on Organic Semiconductor Materials

Organic semiconducting materials have the potential to be used in flexible OLEDs and solar panels. Perylene diimide (PDI) derivatives and 3,4,9,10-Perylenetetracarboxylic dianhydride (PTCDA) are organic semiconducting materials that overcome some of the pitfalls in currently used materials, such as instability under exposure to intense radiation, as in the case of MEH-PPV (Poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]). In this work, we create amorphous films of PDI and then use solvent vapor annealing to align the resulting aggregates. In a second project, we create uniform thin PTCDA films by thermal vapor deposition and use solvent vapor annealing with ammonium hydroxide to convert the films into PTCDI under intense polarized light to create aligned aggregates. We are currently working on isolating the effect of the polarized light on the PTCDA to PTCDI conversion process. We are aiming to study the degradation of organic semiconductor films under intense UV light and design a protective layer to prevent their degradation. For all of the organic semiconductors listed above, we will study the effects of long term exposure to a CO2 rich atmosphere on their stability for potential uses in Mars-bound spacecraft.