Exploring transport properties of stable rubrene derivatives

Crystalline organic semiconductors, such as rubrene, are crucial for addressing the low mobility of organic materials, with rubrene offering high hole mobility of up to 10 cm²/Vs, even in thin films. Thin films are particularly beneficial for scalable device fabrication, having shown success in photodetectors and bipolar transistors, where rubrene supports both n- and p-type doping. However, rubrene's susceptibility to oxygen under UV light limits its stability. To tackle this, novel fluorinated rubrene derivatives were synthesized to reduce oxidation while preserving mobility. Stability under UV light and ambient conditions was studied, alongside device-relevant evaluations, such as HOMO level measurements (via UPS) and conductivity under doping. Crystallization studies compared single and thin-film crystals, analyzing them using XRD and GIWAXS. The acquired data is compared to simulated crystal structures. Thin-film morphology was further characterized using PLM and AFM, providing insights into their structural properties. The compounds with varying degrees of low fluorination pave the way for advanced device engineering and facilitate heteroepitaxial growth on rubrene.