Pyrene is a polycyclic aromatic hydrocarbon consisting of four fused benzene rings known for its strong fluorescence and high photostability. In semiconductor applications, pyrene is often used for its ability to form ordered self-assemblies, which facilitates efficient charge transport. Their large aromatic surface area allows for strong π-π interactions, which improves charge carrier mobility in organic semiconductors. Pyrene has been incorporated into donor-acceptor copolymers to enhance the light-harvesting ability of solar cells. Due to its luminescent properties, pyrene can also be used in OLEDs and other light-emitting devices.