Top-Emitting Active-Matrix Quantum Dot Light-Emitting Diode Array with Optical Microcavity for Micro QLED Display

Kuo-Yang Lai; Shuan Yang; Tung-Chang Tsai; I-An Yao; Chiu-Lien Yang; Chih-Ching Chang; Hsueh-Shih Chen

doi:10.3390/nano12152683

Top-Emitting Active-Matrix Quantum Dot Light-Emitting Diode Array with Optical Microcavity for Micro QLED Display

Nanomaterials (Basel). 2022 Aug 4;12(15):2683. doi: 10.3390/nano12152683.

Authors

Kuo-Yang Lai¹, Shuan Yang², Tung-Chang Tsai³, I-An Yao³, Chiu-Lien Yang³, Chih-Ching Chang⁴, Hsueh-Shih Chen¹

Affiliations

¹ Ph.D. Program in Prospective Functional Materials Industry, College of Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
² Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
³ Technology Development Division, Innolux Corporation, Miaoli 35053, Taiwan.
⁴ Hsinlight Inc., South Campus, National Tsing Hua University, Hsinchu 30013, Taiwan.

Abstract

An electroluminescent quantum-dot light-emitting diode (QLED) device and a micro QLED device array with a top-emitting structure were demonstrated in this study. The QLED device was fabricated in the normal structure of [ITO/Ag/ITO anode]/PEDOT:PSS/PVK/QDs/[ZnO nanoparticles]/Ag/MoO₃, in which the semi-transparent MoO₃-capped Ag cathode and the reflective ITO/metal/ITO (IMI) anode were designed to form an optical microcavity. Compared with conventional bottom-emitting QLED, the microcavity-based top-emitting QLED possessed enhanced optical properties, e.g., ~500% luminance, ~300% current efficiency, and a narrower bandwidth. A 1.49 inch micro QLED panel with 86,400 top-emitting QLED devices in two different sizes (17 × 78 μm² and 74 × 40.5 μm²) on a low-temperature polysilicon (LTPS) backplane was also fabricated, demonstrating the top-emitting QLED with microcavity as a promising structure in future micro display applications.

Keywords: AMQLED; ITO/Ag/ITO; QD; active matrix; microcavity; top emission.

Grants and funding

This research was funded by Innolux Cooperation (Contract No. 108A0228J4), and University Spin-offs TsingYang Technology Inc. (Contract No. 107A0006J4) and HsinLight Inc. (Contract No. 108A0008J4).