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A universal method of micro-patterning thin quantum dot films is highly desired by industry to enable integration of quantum dot materials with optoelectronic devices. Many of the methods reported so far, including specially engineered photoresist or ink-jet printing, are either of poor yield, resolution limited, difficult to scale for mass production, overly expensive or sacrifice some optical quality of the quantum dots. In our previous work, we presented a dry photolithographic lift-off method for pixelization of solution-processed materials and demonstrated its application in patterning perovskite quantum dot pixels, 10 µm in diameter, to construct a static micro-display. In this report, we present further development of this method, and demonstrate high-resolution patterning (~1 µm diameter), full-scale processing on 100 mm wafer, and multi-color integration of two different varieties of quantum dots. Perovskite and cadmium-selenide quantum dots were adopted for the experimentation, but the method can be applied to other types of solution-processed materials. We also show the viability of this method for constructing high-resolution micro-arrays of quantum dot color-convertors by fabricating patterned films directly on top of a blue gallium-nitride LED substrate. The green perovskite quantum dots used for fabrication are synthesized and prepared by our research group via room temperature ligand-assisted reprecipitation method, and these synthesized quantum dots have a photoluminescent quantum yield of 93.6% and full-width half-maximum emission linewidth less than 20 nm. Our results demonstrate the viability of this method for use in scalable manufacturing of high-resolution micro-displays.
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Early defect identification for micro light‐emitting diode displays via photoluminescent and cathodoluminescent imaging
Abstract Ultrahigh‐resolution micro light‐emitting diode (LED) displays are emerging as a viable technology for self‐emissive displays. Several of the critical issues facing micro LED displays with millions of pixels are fidelity, process control, and defect analysis during LED fabrication and transfer. Here, we investigate two non‐destructive test methods, photoluminescent and cathodoluminescent imaging, and compare them with electroluminescent images to verify LED fidelity and evaluate these methods as potential tools for defect analysis. We show that utilizing cathodoluminescent imaging as an analysis tool provides a rich data set that can identify and categorize common defects during micro LED display fabrication that correspond to electroluminescence. Photoluminescent imaging, however, is not an effective method for fidelity analysis but does provide information on dry‐etching uniformity.
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- Award ID(s):
- 1926747
- PAR ID:
- 10258860
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of the Society for Information Display
- Volume:
- 29
- Issue:
- 4
- ISSN:
- 1071-0922
- Format(s):
- Medium: X Size: p. 264-274
- Size(s):
- p. 264-274
- Sponsoring Org:
- National Science Foundation
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