Highly efficient printed quantum dot light-emitting diodes through ultrahigh-definition double-layer transfer printing

Abstract

Highly efficient and high-definition displays with deformable form factors are highly desirable for next-generation electronic devices. Despite the unique advantages of quantum dots (QDs), including high photoluminescence quantum yield, wide colour range and high colour purity, developing a QD patterning process for high-definition pixels and efficient QD light-emitting diodes (QLEDs) is in its early stages. Here we present highly efficient QLEDs through ultrahigh-definition double-layer transfer printing of a QD/ZnO film. Surface engineering of viscoelastic stamps enables double-layer transfer printing that can create RGB pixelated patterns with 2,565 pixels per inch and monochromic QD patterns with similar to 20,526 pixels per inch. The close packing of both QDs and ZnO nanoparticles by double-layer transfer printing substantially minimizes the leakage current, enhancing the external quantum efficiency of our devices to 23.3%. Furthermore, we demonstrate highly efficient wearable QLEDs fabricated by our technique. This study paves the way for the development of highly efficient, full-colour QD displays via the transfer printing technique, demonstrating great promise for next-generation display technologies.