As an organic semiconductor, the major application of rubrene is in organic light-emitting diodes (OLEDs) and organic field-effect transistors, which are the core elements of flexible displays. Single-crystal transistors can be prepared using crystalline rubrene, which is grown in a modified zone furnace on a temperature gradient. This technique, known as physical vapor transport, was introduced in 1998.[2][3]
Rubrene holds the distinction of being the organic semiconductor with the highest carrier mobility, reaching 40 cm2/(V·s) for holes. This value was measured in OFETs prepared by peeling a thin layer of single-crystalline rubrene and transferring to a Si/SiO2 substrate.[4]
Crystal structure
Several polymorphs of rubrene are known. Crystals grown from vapor in vacuum can be monoclinic,[5]triclinic,[6] and orthorhombic motifs.[7] Orthorhombic crystals (space group Bbam) are obtained in a closed system in a two-zone furnace at ambient pressure.[8]
Rubrene, like other polycyclic aromatic molecules, undergoes redox reactions in solution. It oxidizes and reduces reversibly at 0.95 V and −1.37 V, respectively vs SCE. When the cation and anion are co-generated in an electrochemical cell, they can combine with annihilation of their charges, but producing an excited rubrene molecule that emits at 540 nm. This phenomenon is called electrochemiluminescence.[11]
^Taylor, W. H. (1936). "X-ray measurements on diflavylene, rubrene, and related compounds". Zeitschrift für Kristallographie. 93 (1–6): 151. doi:10.1524/zkri.1936.93.1.151. S2CID101491070.
^Akopyan, S. A.; Avoyan, R. L. and Struchkov, Yu. T. Z. Strukt. Khim. 3, 602 (1962)
^Henn, D. E. & Williams, W. G. (1971). "Crystallographic data for an orthorhombic form of rubrene". J. Appl. Crystallogr. 4 (3): 256. doi:10.1107/S0021889871006812.
