Efficient larger size white quantum dots light emitting diodes using blade coating at ambient conditions

Abstract

Here, we propose a facile strategy to realize all-solution-processed highly efficient full-color-enabling white emitting quantum dot light-emitting diodes (QLEDs) at ambient conditions by using low-cost blade coating technique, which was also compatible with the roll to roll fabrication process for large size production. Firstly, by using red quantum dots (QDs) as the representative to optimize the QDs films by blade coating, the QDs films exhibit excellent morphology and well-ordered self-assembly structure. Then, the trichromatic white QLEDs based on mixed red, green and blue quantum dots were obtained with Commission Internationale De I'Eclairage (CIE) coordinates ranging from (0.42, 0.41) to (0.31, 0.33) within the white region of CIE 1931 when driving voltage vary from 5 v to 8 v. The device enjoys excellent optoelectronic performance including a maximum luminance of 11,465 cd/m 2 , a maximum current efficiency ( η A ) of 9.2 cd/A and an external quantum efficiency (EQE) of 3.7%. In addition, 3 × 8 cm 2 white QLEDs with bright and homogenous light emission fabricated by blade coating are demonstrated. Our strategy for fabricating large-area white QLEDs indicate promising applications in the low-cost solid-state lighting and flat-panel displays. • The QDs films exhibit excellent morphology and well-ordered self-assembly structure by blade coating. • The trichromatic white QLEDs were obtained with a maximum luminance of 11,465 cd/m 2 , η A of 9.2 cd/A and EQE of 3.7%. • 3×8 cm 2 white QLEDs with bright and homogenous light emission fabricated are demonstrated.