PTCDA

3,4,9,10-Perylenetetracarboxylic dianhydride, also known as Perylenetetracarboxylic acid dianhydride, is a large π-conjugated semiconductor aromatic organic molecule. It is an organic dye molecule and an organic semiconductor. It is used as a precursor to a class of molecules known as Rylene dyes, which are useful as pigments and dyes. It is a dark red solid with low solubility in aromatic solvents.
The compound has attracted much interest as an organic semiconductor. It has potential applications in organic and molecular electronics, and typically used as an archetype molecular compound. PTCDA shares many properties with conventional semiconductors (with their delocalized electronic states), and insulator-like organic molecular crystals (OMCs) (with their large absorption oscillator strengths, excitonic self-trapping, polaron-assisted conduction, etc.). That is due to extremely close π-π stacking, an unusually small intermolecular distance of only 3.21 A. Among its applications, it is important to highlight the latest focus on environment monitoring, self-assembly and photocatalysis.