Enhancing the reliability of InP-based QD color conversion layer through a uniform organic encapsulation layer via inkjet printing

Abstract

Quantum dot (QD) as a color conversion layer (CCL) is gaining increasing attention for use in next generation displays. However, QD CCL, especially those based on indium phosphide (InP) materials, are vulnerable to oxygen and moisture. Accordingly, even in CCL technology, encapsulation is essential to mitigate performance reduction due to the degradation of color conversion efficiency (CCE). Herein, we employed only acrylic-based resin to produce a uniform encapsulation layer on a CCL, enhancing the CCE reliability of the QD CCL under ambient conditions. To print a uniform encapsulation layer, we confirmed the significance of the minimized surface energy differences on glass, bank, and QD film through O₂ plasma treatment. We also investigated coating characteristics through adjustment of the drop spacing to analyze the reliability of the CCL. Compared to the CCL without an encapsulation layer, the CCE only showed a decrease of 1.96 % at green and 3.6 % at red light, after 168 h. The T95 (time to 95 % of the initial luminance) was improved from 5.25 h to 75.02 h by applying the encapsulation layer. As a result, we enhanced the stability of the InP-based QD CCL by printing only an organic encapsulation layer using the inkjet printing process.