Electron-Rich 4-Substituted Spirobifluorenes: Toward a New Family of High Triplet Energy Host Materials for High-Efficiency Green and Sky Blue Phosphorescent OLEDs

Cassandre Quinton (1) , Sébastien Thiery (1) , Olivier Jeannin (1) , Denis Tondelier (2) , Bernard Geffroy (2, 3) , Emmanuel Jacques (4) , Joëlle Rault-Berthelot (1) , Cyril Poriel (1)

1 ISCR - Institut des Sciences Chimiques de Rennes
2 LPICM - Laboratoire de physique des interfaces et des couches minces [Palaiseau]
3 LICSEN - Laboratoire Innovation en Chimie des Surfaces et NanoSciences
4 IETR - Institut d'Électronique et des Technologies du numéRique

We report herein a detailed structure-properties relationship study of the first examples of electron-rich 4-substituted spirobifluorenes for organic electronic applications, namely, 4-phenyl-N-carbazole-spirobifluorene (4-PhCz-SBF) and 4-(3,4,5-trimethoxyphenyl)-spirobifluorene (4-Ph(OMe)-SBF). The incorporation of the electron-rich moieties in the ortho position of the biphenyl linkage (position C4) induces unique properties, very different from those previously described in the literature for this family of semiconductors. Both dyes can be readily synthesized, possess high triplet energies and excellent thermal stability, and their HOMO energy levels are highly increased compared to those of other 4-substituted SBFs. We also provide in this work the first rationalization of the peculiar fluorescence of 4-substituted SBFs. Finally, the present dyes have been successfully incorporated as host in green and blue phosphorescent organic light-emitting diodes with high performance either for the green (EQE of 20.2%) or the blue color (EQE of 9.6%). These performances are, to the best of our knowledge, among the highest reported to date for 4-substituted SBF derivatives.

Keywords: organic electronics; host materials; 4-substituted spirobifluorene; blue phosphorescent organic light-emitting diode; conjugation disruption; organic semiconductors

Domains: Chemical Sciences; Material chemistry; Chemical Sciences; Organic chemistry

Cassandre Quinton, Sébastien Thiery, Olivier Jeannin, Denis Tondelier, Bernard Geffroy, et al.. Electron-Rich 4-Substituted Spirobifluorenes: Toward a New Family of High Triplet Energy Host Materials for High-Efficiency Green and Sky Blue Phosphorescent OLEDs. ACS Applied Materials & Interfaces, 2017, 9 (7), pp.6194-6206. ⟨10.1021/acsami.6b14285⟩. ⟨hal-01475815⟩