Controlling of thickness profile in micro-scale pixels via an inkjet printing process remains a challenge and strict control of surface energy is required. Herein, the surface energy of each substrate is controlled by using CF4 plasma treatment (CPT) to control thickness profile and improve color conversion efficiency (CCE) of the inkjet printed quantum dots (QDs) color conversion layer (CCL). The bank surface becomes hydrophobic due to the fluorination, while the glass becomes hydrophilic due to the cleaning effect by the CPT. Through a systemic investigation of the polar and non-polar components of the surface energy, it is found that the ink behavior of inkjet-printed QDs in the pixels is closely related to the non-polar component of the surface energy. In addition, it is found that more rigorous control of the surface is required for array printing and a wide range of thickness profile control is possible by CPT. The thickness increases by up to 10 µm, the blue leakage is reduced by 26.38%, and the CCE increases by a maximum of 5.71% depending on the CPT. As a result, the relationship between the thickness profile of the CCL and CCE is confirmed through the fabrication of QD-organic light emitting diodes.
Bibliographical noteFunding Information:
This study was conducted with the support of the Ministry of Trade, Industry and Energy (MOTIE, Grant No. 20016350).
© 2022 The Authors. Advanced Materials Interfaces published by Wiley-VCH GmbH.
- CF plasma treatment
- color conversion
- inkjet printing
- quantum dots
- surface energy
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering