Stacked Encapsulation Structure for Discretely Distributed Quantum Dot Array

• Main Authors: Jing Cai, Jianyao Lin, Yu Chen, Sheng Xu, Yun Ye, Enguo Chen, Tailiang Guo
• Format: Article
• Language: English
• Published: IEEE 2020-01-01
• Series: IEEE Photonics Journal
• Subjects: Quantum-dot array; moisture; oxygen; encapsulation; stacked structure.
• Online Access: https://ieeexplore.ieee.org/document/9018060/

The performances of quantum-dot (QD) based photoluminescent devices are highly restricted by the application environment, especially the moisture and oxygen. However, current external encapsulation structures are not applicable to the devices with discrete QD distribution, especially for some rough profiles. To address this issue, an encapsulation method for discretely distributed quantum-dot arrays (DQDA) is proposed for liquid crystal display (LCD) backlight applications, in which the DQDA can be well fabricated by printing the QD slurry onto a light guiding substrate (LGS), and then covered with a thin UV glue layer and a barrier film. By specially optimizing the UV glue and barrier film, this ultra-thin encapsulation structure cannot only improve the surface defects of the QD morphology without affecting the original light path and the output optical performance, but also significantly suppress the fluorescence decay and isolate moisture and oxygen by almost 100 times compared with unencapsulated one. The water vapor transmission rate (WVTR) was measured to be 1.29 × 10^-4 g/m²/day after fabricated the stacked encapsulation structure. After a long period of aging test, the encapsulated sample kept its luminance for 1000 hours. This method also has potential to widely used for discrete structures in other device applications due to its easy fabrication process, high reliability, and low manufacturing costs.