199297-08-0Relevant articles and documents
Dendron engineering in self-host blue iridium dendrimers towards low-voltage-driving and power-efficient nondoped electrophosphorescent devices
Wang, Yang,Wang, Shumeng,Ding, Junqiao,Wang, Lixiang,Jing, Xiabin,Wang, Fosong
, p. 180 - 183 (2016/12/27)
Dendron engineering in self-host blue Ir dendrimers is reported to develop power-efficient nondoped electrophosphorescent devices for the first time, which can be operated at low voltage close to the theoretical limit (Eg/e: corresponding to the optical bandgap divided by the electron charge). With increasing dendron's HOMO energy levels from B-POCz to B-CzCz and B-CzTA, effective hole injection is favored to promote exciton formation, resulting in a significant reduction of driving voltage and improvement of power efficiency. Consequently, the nondoped device of B-CzTA achieves extremely low driving voltages of 2.7/3.4/4.4 V and record high power efficiencies of 30.3/24.4/16.3 lm W?1 at 1, 100 and 1000 cd m?2, respectively. We believe that this work will pave the way to the design of novel power-efficient self-host blue phosphorescent dendrimers used for energy-saving displays and solid-state lightings.
Novel functional materials based on triarylamines-synthesis and application in electroluminescent devices and photorefractive systems
Thelakkat, Mukundan,Schmitz, Christoph,Hohle, Christoph,Strohriegl, Peter,Schmidt, Hans-Werner,Hofmann, Uwe,Schloter, Stefan,Haarer, Dietrich
, p. 1693 - 1698 (2007/10/03)
A variety of new functional materials based on triarylamines, such as low molecular weight glasses which possess hole conducting/photoconductive properties as well as amorphous bifunctional materials which combine photoconductive and non-linear optical (NLO) properties in one compound, have been synthesized. The new hole transporting glasses belong to the class of 1,3,5-tris(triaryldiamino)benzenes (TTADB). The hyperbranched structure and the large aryl groups attached as substituents lead to high glass transition temperatures (T(g)) of up to 141 °C in these compounds. The TTADBs do not recrystallize upon cooling from the melt, but form stable glasses. Cyclic voltammetry studies reveal multi-oxidation stages for these compounds of which the first oxidation is reversible. The HOMO energy values determined from CV for TTADB-1 and TTADB-2 are -4.82 and -4.94 eV, respectively. Light emitting diodes with the structure ITO/TTADB-2/Alq3/Al (where ITO = indium tin oxide) show high efficiency and large current carrying capacity. Further, bifunctional compounds have been synthesized in which a photoconductive moiety such as bis(carbazolyl)triphenylamine or bis(diphenylamino)triphenylamine is covalently bound to different NLO chromophores. Some of these compounds are thermally and morphologically stable amorphous materials, possessing T(g) in the range from 85 to 122 °C. Cyclic voltammetry measurements reveal that the HOMO energy values are between -4.81 and -5.45 eV. In photorefractive measurements using 40 μm thick samples, a diffraction efficiency of 27%, which corresponds to a refractive index modulation (Δn) of 3.5 x 10-3, a maximum two beam coupling gain coefficient (Γ) of 90 cm-1 and a response time of 40 ms were obtained.
