Uniformity and Stability of Quantum Dot Pixels Evaluated by Microscale Fluorescence Spectroscopy. Issue 8 (9th June 2022)

• Record Type: Journal Article
• Authors: Shi, Shuchen; Bai, Wenhao; Lin, Cunjian; Xuan, Tongtong; Dong, Guoyan; Huang, Fan; Xie, Rong‐Jun
• Is Part Of: Laser & photonics reviews. Volume 16:Issue 8(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-09
• Subjects: color conversion films -- emissive displays -- micro‐LED -- optical spectroscopy -- quantum dots; Lasers -- Periodicals; Photonics -- Periodicals; Lasers -- Périodiques; Photonique -- Périodiques; 621.36
• DOI: 10.1002/lpor.202100699
• Languages: English
• ISSNs: 1863-8880

Abstract

Abstract: Quantum dot color conversion films (QD‐CCFs) are proposed for use in full‐color micron‐sized light‐emitting diode (micro‐LED) displays, but quickly and precisely evaluating their optical quality and identifying the bad pixels among them remain challenging. In this work, microscale fluorescence spectroscopy (MFS) is demonstrated to investigate the photoluminescence uniformity and stability of red‐emitting CdSe/CdS/ZnS QD‐CCF pixels prepared by high‐resolution inkjet printing. The photoluminescence (PL) intensity imaging, together with the PL spectrum, lifetime imaging, and time‐dependent PL intensity curve, enables accurate analysis of the luminescence uniformity and thermal and light stability of QD‐CCFs. The coffee rings in QD‐CCF pixels can be clearly identified by MFS, which are missed by a conventional fluorescence microscope. It thus provides feedback for tailoring the composition and properties of ink to eliminate coffee rings or other defects. The combination of MFS with machine learning will likely realize the "massive detection" of QD‐CCFs for micro‐LEDs. Abstract : A new microscale fluorescence spectroscopy system is demonstrated to accurately analyze the uniformity and stability of quantum dot color conversion films for micro‐LED displays. The photoluminescence (PL) uniformity and stability of each red CdSe/CdS/ZnS QD‐CCF pixel are investigated, including imaging of the PL intensity and lifetime, time‐dependent PL intensity curve, and PL spectra of the micro area at different temperatures.