1610503-97-3Relevant academic research and scientific papers
2-Substituted vs 4-substituted-9,9'-spirobifluorene host materials for green and blue phosphorescent OLEDs: A structure-property relationship study
Thiery, Sébastien,Declairieux, Céline,Tondelier, Denis,Seo, Gijun,Geffroy, Bernard,Jeannin, Olivier,Métivier, Rémi,Rault-Berthelot, Jo?lle,Poriel, Cyril
, p. 6337 - 6351 (2015)
Abstract 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: CE58 cd/A, PE35 lm/W, EQE14%). More importantly, the two 4-substituted SBFs have been used as host materials in blue PhOLEDs, displaying high performance and a decrease of VnfTH/inf for 4-5Pm-SBF due to the incorporation of the electron-withdrawing pyrimidine.
9,9′-Spirobifluorene and 4-phenyl-9,9′-spirobifluorene: Pure hydrocarbon small molecules as hosts for efficient green and blue PhOLEDs
Thiery, Sebastien,Tondelier, Denis,Declairieux, Celine,Seo, Gijun,Geffroy, Bernard,Jeannin, Olivier,Rault-Berthelot, Joelle,Metivier, Remi,Poriel, Cyril
, p. 4156 - 4166 (2014/06/09)
We report herein a new pure hydrocarbon material, 4-phenyl-9,9′- spirobifluorene (4-Ph-SBF), with a high triplet energy level (ET: 2.77 eV) as a host for blue phosphorescent organic light-emitting diodes (PhOLEDs). Structural, thermal, electrochemical and photophysical properties have been investigated in detail and compared to its constituting building block 9,9′-spirobifluorene (SBF) in order to precisely study the influence of the incorporation of a phenyl unit in C4. A surprising out of plane deformation of the fluorene ring and a highly twisted structure have been notably found for 4-Ph-SBF due to the substitution in C4. As both 4-Ph-SBF and SBF possess a high triplet energy level (2.77/2.87 eV resp.), they have been successfully used as host materials for green and blue PhOLEDs. The performance of blue PhOLEDs, ca. 20 cd A-1, appears to be among the highest reported for pure hydrocarbon derivatives.
