Synthesis of Polymers Having a Hole Transporting Ability by Condensation Polymerization of N,N‘-Diphenyl-N,N‘-bis(4-methylphenyl)-(1,1‘-biphenyl)-4,4‘-diamine and Aldehydes

Abstract

Novel polymers having a hole transport ability were prepared by condensation polymerization of N,N‘-diphenyl-N,N‘-bis(4-methylphenyl)-(1,1‘-biphenyl)-4,4‘-diamine (TPD) and paraformaldehyde (FA) or benzaldehyde (BzA). From NMR spectra, it is revealed that addition condensation reactions occurred exclusively at the para positions of TPD. TPD−FA polymer was linked not only by a methylene linkage but also by a methylene ether linkage, while TPD−BzA polymer was only linked by a methine linkage. The glass transition temperatures of TPD−FA and TPD−BzA were 183 and 239 °C, respectively. The drift mobility of TPD−BzA measured by a standard time-of-flight (TOF) method was found to be on the order of 10-5 and 10-6 cm2/(V s). The multilayer EL devices were fabricated using TPD−FA and TPD−BzA polymers as a hole transport layer and Alq as an electron transport emitting layer. In both devices, the initial driving voltage is about 4 V, and the maximum luminance is above 10 000 cd/m2 at 14 V. It is expected that these polymers can be used as a hole transport material in the EL device.

Novel trends of electrochemical oxidation of amino-substituted triphenylamine derivatives

“…When the electrolysis potentials were set at the second-electron oxidation potentials, only 2b 2+ could be recovered to 2b +Å by 80%. The other two derivatives (2) and (2a) became dark black and some small black particles floating in the solution were observed. Apparently, the dications are not stable and may undergo decomposition or complicated oxidation reactions.…”

“…The stability of the cation radical varies markedly with para-substitution. Because of the low ionization potentials, reversible redox behavior and good film-forming properties [2,3], TPA-containing monomers [1,4] and polymers [3] have been synthesized and their charge injection and electroluminescent efficiency have been studied [4][5][6][7]. Today, the highly electron-rich TPA derivatives have been chosen as important candidates for electrical and optical applications such as organic photoconductors, electroluminescence and electrochromic devices [8][9][10].…”

Synthesis and Characterization of Hyperbranched Polymer Having Hole Transporting Ability

“…It is reported that the signal at 3.8 ppm can be assigned to a methylene proton linked with para position and the signal at 3.6 ppm to a methylene proton linked with meta positions. 29 Optical Properties Measured by UV-Vis and PL Measurements Figure 3 shows UV absorption spectra of LP and HBP in toluene solution. The UV spectra are similar, with an absorption maximum at 319 nm.…”

Novel aromatic polymers from benzaldehyde and triphenylamine derivatives: Synthesis, electrochromic, and photochemical properties

“…Our strategy in this article is to synthesize high‐yield TPA‐containing monomers by easier procedure, and then react with the commercially available commodity benzaldehyde through an acid catalyzed polymerization. Sato and coworkers32, 33 and Shikatani et al34 reported that reaction of TPA derivatives with various aldehydes provided hole transporting materials, but the electrochromic properties of the obtained polymers were not investigated. Nishikitani et al35 also reported the similar result; however, they introduced alkyl group in N ‐position that might cause not only less conjugation cation radical form but also lower their glass transition temperatures ( T g s) and thermal stability.…”