Synthesis and characterization of thermally cross-linkable trimer based on triphenylamine

• Published in: Macromolecular research Vol. 21; no. 3; pp. 321 - 326
• Main Authors: Hong, Heeseob, Jo, Mi Young, Ha, Ye Eun, Kim, Joo Hyun
• Format: Journal Article
• Language: English
• Published: Heidelberg The Polymer Society of Korea 01-03-2013; 한국고분자학회
• Subjects: Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Nanochemistry; Nanotechnology; Physical Chemistry; Polymer Sciences; Soft and Granular Matter; 고분자공학; hole injection/transporting material; thermal curing; oligotriphenylamine; buffer layer
• ISSN: 1598-5032; 2092-7673
• DOI: 10.1007/s13233-013-1116-4

A trimer with thermally crosslinkable vinyl groups, (4-butyl-phenyl)-bis-[4-((4-vinyl-phenyl)-(4-butyl-phenyl)-phenyl-amine)-phenyl]-amine (
3-TPA
), was synthesized successfully. Differential scanning calorimetry (DSC) thermogram of
3-TPA
showed two endothermic processes at 122 and 218 °C at the first heating scan. The endothermic peak at 122 °C corresponds to the melting behavior of
3-TPA
and the other at 218 °C seems to be from thermal crosslinking. Thermally cured
3-TPA
film at 180 °C for 1 h showed very good solvent resistance and was electrochemically stable. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of cured
3-TPA
film was −5.09 and −2.10 eV, respectively. The turn on electric field of PLEDs with cured
3-TPA
was 1.37–1.80 MV/cm, which was smaller than that of the device without
3-TPA
(2.51 MV/cm). The luminance efficiency and brightness of polymer light-emitting diodes (PLEDs) based on
3-TPA
were much higher than that of the PLED without
3-TPA
. This is due to that cured
3-TPA
has hole injection and transporting property. Among the PLEDs, the device with a 20 nm-thick cured
3-TPA
showed the best performance with a maximum efficiency of 1.29 cd/A and a maximum brightnes of 2,500 cd/m
2
.