DiSpiroXanthene-IndenoFluorene: A New Blue Emitter for Nondoped Organic Light Emitting Diode Applications

Abstract

Through an expedient synthesis, a novel blue emitter, DiSpiroXanthene-IndenoFluorene (DSX-IF) has been designed and synthesized. DSX-IF possesses good morphological and color stability upon heating, has a high quantum yield, and may be easily polymerized through anodic oxidation. Small molecule organic light emitting diodes (SMOLEDs), using this promising new dixanthene derivative as a blue emissive layer, exhibit a maximum luminance of ca. 3800 Cd.m(-2) with a luminous efficiency of 1 Cd.A(-1).

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

“…In addition, the small Stokes-Shift of 5 nm, calculated from the difference between the lowest energy absorption band (340 nm) and the highest energy emission band (345 nm), is perfectly explained by the similar geometries of S0 and S1 (figure 7-middle). This is a significant difference with 4-Ph(OMe) 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 its solution spectrum. This may indicate strong interactions in the solid state, which can be attributed to the phenyl-carbazole fragment in accordance with the short C/C distances observed in the crystal packing...…”

“…We want to provide herein the beginning of an answer. We indeed believe that this large Stokes shift can be explained by the significant differences between the geometries of the ground (S0) and first singlet excited (S1) states observed for both 4-Ph(OMe) 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 that the geometry difference between S0 and S1 is more pronounced for 4-Ph(OMe) 3 -SBF than for 4-Ph-SBF, clearly explaining the difference observed in term of Stokes shift. Furthermore, this low rigidity (allowing an important rearrangement at the excited state) could be the reason of the large and unresolved fluorescence spectra of these two molecules.…”

“…consists 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 For all functionals, this band experimentally found at 309 nm is due to two transitions (λ 1 and λ 2 , 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 The main absorption band of 4-Ph(OMe) 3 …”

“…Finally, one can note that, contrary to SBF and 4-Ph-SBF which both present a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 short C/H intermolecular distances are also detected (dC/H = 2.84-2.89 Å, see SI), being slightly shorter than the sum of the van der Waals radii. 46 However, in the case of 4-Ph(OMe) 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 First, in reduction (figures in SI), no wave was detected in dichloromethane and the LUMO energy levels of the two compounds were determined from the ...…”

“…In addition, both dyes display very different fluorescence properties and we provide herein the first rationalization of the peculiar fluorescence of 4-substituted SBFs. Finally, both 4-PhCz-SBF and 4-Ph(OMe) 3 -SBF have been successfully incorporated as host in green and blue PhOLEDs displaying a high efficiency. Thus, the green and blue PhOLEDs using 4-Ph(OMe) 3 -SBF as host display a high EQE of 20.2% and 9.6% respectively.…”