Spirosilabifluorene linked bistriphenylamine: Synthesis and application in hole transporting and two-photon fluorescent imaging

Spirosila-BF-TPA, in which two identical triphenylamines linked orthogonally around a spirosilabifluorene core, has been synthesized and characterized. The introduction of a spiro linkage into the structure of spirosila-BF-TPA leads to a reduction in crystallization tendency and no glass transition temperature was observed. Spirosila-BF-TPA exhibits blue emission around 410 nm. Its reversible electrochemical oxidation and low ionization potential (5.33 eV) suggest that spirosila-BF-TPA might have potential application as a hole transporting material. The hole transport ability of spirosila-BF-TPA was tested by comparing the performance of the two types of OLED devices. According to the fluorescence images of spirosila-BF-TPA films, it was found that the two-photon fluorescence of spirosila-BF-TPA is intensive, which implies that this molecule is also a promising candidate for an application such as two-photon microscopy and imaging.