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Enhanced Performance of Pixelated Quantum Dot Light‐Emitting Diodes by Inkjet Printing of Quantum Dot–Polymer Composites
Author(s) -
Roh Heebum,
Ko Donghyun,
Shin Dong Yeol,
Chang Jun Hyuk,
Hahm Donghyo,
Bae Wan Ki,
Lee Changhee,
Kim Jun Young,
Kwak Jeonghun
Publication year - 2021
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.202002129
Subject(s) - quantum dot , materials science , optoelectronics , inkjet printing , composite number , fabrication , light emitting diode , diode , composite material , nanotechnology , inkwell , medicine , alternative medicine , pathology
Inkjet printing of colloidal quantum dots (QDs) is considered a promising technology for application in full‐color quantum dot light‐emitting diode (QLED) displays. However, QLEDs that are inkjet printed in a pixel‐defining bank structure generally exhibit a low performance, mainly due to the nonuniformity in its QD morphology. In this study, an enhanced performance of inkjet‐printing‐based pixelated QLEDs is achieved by introducing small amounts of poly(methyl methacrylate) (PMMA) of different molecular weights into QD inks. When this QD–PMMA composite ink is adopted, uniform droplets are formed, originating from contact line depinning during drying. Inside the bank structure, the inkjet‐printed QD–PMMA composite film shows a smooth surface and little pileup at the bank edges. A pixelated QLED with PMMA with a molecular weight of 8 kDa exhibits the highest luminance of 73 360 cd m −2 and an external quantum efficiency of 2.8%, which are remarkably higher than that of the inkjet‐printed QLED subpixels without PMMA. The result is verified through the observation of the drying process and the QLED subpixel shapes under operation. Thus, inkjet‐printed QD–PMMA composite inks can be a promising strategy for future research on pixelated QLEDs for the fabrication process of full‐color QLED displays.