RESUMO
We report herein the incorporation of xanthenyl units into two extended π-conjugated phenylene systems, namely indenofluorene and pentaphenylene. Thus, dispiroxanthene-indenofluorene (DSX-IF) and dispiroxanthene-ladderpentaphenylene (DSX-LPP) have been designed and synthesized through short and efficient synthetic approaches. These two molecules possess a 3π-2-spiro architecture (3π-systems/2-spiro bridges), in which two xanthenyl cores are spirolinked to a π-conjugated backbone either indenofluorene for DSX-IF or pentaphenylene for DSX-LPP. The structural, electrochemical, and photophysical properties of these blue/violet emitters have been studied in detail and compared to those of their 'all carbon' analogues with spirofluorenyl cores instead of spiroxanthenyl cores, namely dispirofluorene-indenofluorene (DSF-IF) and dispirofluorene-ladderpentaphenylene (DSF-LPP), previously reported in the literature. Finally, the application of DSX-IF and DSX-LPP as new light-emitting materials in nondoped organic light emitting diodes is reported. A detailed optical study of the different electroluminescence spectra is notably presented, with an emphasis 1) on the origin of the low-energy emission band observed in the case of DSX-LPP and 2) on the unexpected optical contribution of the well-known hole-transporting-layer NPB (N,N'-di(naphtyl)-N,N'-diphenyl(1,1'-biphenyl)-4,4'-diamine).
RESUMO
Extended hybrid conjugated systems based on a trithienylphenylamine core with 1, 2 and 3 peripheral dithiafulvenyl units have been synthesized and studied by cyclic voltammetry and UV-Vis. absorption spectroscopy. Theoretical calculations have also been undergone. The behaviour of these derivatives which depends on the number of dithiafulvene moieties grafted of the central core is cleared up. One polymer, obtained from derivative 3 presents polyelectrochromic properties.
RESUMO
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).
RESUMO
New routes to ladder-type phenylene materials 1 and 2 are described. The oligomers 1 and 2, which possess a "3pi-2spiro" architecture, have been synthesized by using extended diketone derivatives 3 and 10 as key intermediates. The physicochemical properties of the new blue-light emitter 2 were studied in detail and compared with those of the less-extended 1. Owing to the recent development of fluorenone derivatives and their corresponding more conjugated analogues as potential electron-transport materials in organic light-emitting diodes (OLEDs) and as n-type materials for photovoltaic applications, we also report herein the thermal, optical and electrochemical behavior of the key intermediates, diketones 3 and 10. Finally, the application of dispiro 2 as a new light-emitting material in OLEDs is reported.
RESUMO
A series of new dispiro[fluorene-9',6,9'',12-indeno[1,2b]fluorenes] (DSF-IFs) has been synthesised. These new building blocks for blue-light-emitting devices and electroactive polymers combine indenofluorene (IF) and spirobifluorene (SBF) properties. We report here our synthetic investigations towards these new structures and their thermal, structural, photophysical and electrochemical properties. These properties have been compared to those of IF and SBF. We also report the anodic oxidation of DSF-IFs that leads to the formation of non-soluble transparent three-dimensional polymers. The structural and electrochemical behaviour of these polymers has been studied. The first application of these building blocks as new blue-light-emitting materials in organic light-emitting diodes (OLED) is also reported.
