| Title |
Coating Properties of a TPD Organic Hole-transporting Layer Deposited using a Continuous slot-die Coating Method |
| Authors |
정국채(Kook Chae Chung); 김영국(Young Kuk Kim); 최철진(Chul Jin Choi) |
| DOI |
https://doi.org/10.3365/KJMM.2010.48.04.363 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
optoelectronic materials; coating; surface; AFM; roughness |
| Abstract |
N,N`-diphenyl-N,N`-bis(3-methylphenyl)1-1` biphenyl-4,4`-diamine (TPD) hole-transporting layers were deposited using a continuous slot-die coating method on ITO/PET flexible substrates. It is crucial that the substrates have a very smooth surface with a RMS roughness of less than 2 nm for the deposition of semiconductor nanocrystals or Quantum Dots. The parameters of the slot-die coating, including the solution concentration of the TPD, the gap between the slot-die and the substrates, and the coating speed were controlled in these experiments. To obtain full coverage of the TPD films on the ITO/PET substrates (40 mm wide and several meters long), the injection rates of the TPD solution were increased proportional to the coating speed of the flexible substrates. Additionally, the injection rates must be increased as the gap distance changes from 400 to 600 μm at the same coating speed. A RMS surface roughness of less than 2 nm was obtained, in contrast to bare ITO/PET substrates, at 13 nm, as the coating speed and gap distance increased. (Received October 17, 2009) |