2-Substituted vs 4-substituted-9,9′-spirobifluorene host materials for green and blue phosphorescent OLEDs: a structure-property relationship study

Sebastien Thiery (1) , Céline Declairieux (2) , Denis Tondelier (2) , Gijun Seo (2) , Bernard Geffroy (2, 3) , Olivier Jeannin (1) , Rémi Métivier (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 PPSM - Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires

We report a structure-property relationship study of four 9,9′-spirobifluorene (SBF) derivatives (4-5Pm-SBF, 2-5Pm-SBF, 4-Ph-SBF and 2-Ph-SBF), substituted with either phenyl or pyrimidine at the \C2\ or \C4\ position of the \SBF\ core. Structural, thermal, electrochemical and photophysical properties have been examined and correlated to theoretical calculations in order to study the influence of the nature and the position of the substituent. The emission properties of 4- versus 2-substituted \SBFs\ are noticeably different highlighting, in the excited state, the remarkable effect of substitution in ortho position of SBF. All compounds have been used as host material for green dopant in PhOLEDs with very high performances (2-5Pm-SBF: CE>58 cd/A, PE>35 lm/W, EQE>14%). More importantly, the two 4-substituted \SBFs\ have been used as host materials in blue PhOLEDs, displaying high performance and a decrease of \VTH\ for 4-5Pm-SBF due to the incorporation of the electron-withdrawing pyrimidine.

Keywords: Pyrimidine; Conjugation disruption; Organic electronics; Host material; Blue phosphorescent organic light emitting diodes; Organic semiconductors; 4-Substituted spirobifluorenes

Domains: Chemical Sciences; Organic chemistry

Sebastien Thiery, Céline Declairieux, Denis Tondelier, Gijun Seo, Bernard Geffroy, et al.. 2-Substituted vs 4-substituted-9,9′-spirobifluorene host materials for green and blue phosphorescent OLEDs: a structure-property relationship study. Tetrahedron, 2014, 70 (36), pp.6337 - 6351. ⟨10.1016/j.tet.2014.05.081⟩. ⟨hal-01072178⟩