Heterogeneous stacking of nanodot monolayers by dry pick-and-place transfer and its applications in quantum dot light-emitting diodes

Abstract

Layered assembly structures composed of nanomaterials, such as nanocrystals, have attracted considerable attention as promising candidates for new functional devices whose optical, electromagnetic and electronic behaviours are determined by the spatial arrangement of component elements. However, difficulties in handling each constituent layer in a materialspecific manner limit the 3D integration of disparate nanomaterials into the appropriate heterogeneous electronics. Here we report a pick-and-place transfer method that enables the transfer of large-area nanodot assemblies. This solvent-free transfer utilizes a lifting layer and allows for the reliable transfer of a quantum dot (QD) monolayer, enabling layer-by-layer design. With the controlled multistacking of different bandgap QD layers, we are able to probe the interlayer energy transfer among different QD monolayers. By controlling the emission spectrum through such designed monolayer stacking, we have achieved white emission with stable optoelectronic properties, the closest to pure white among the QD lightemitting diodes reported so far.

Flexible quantum dot light-emitting diodes for next-generation displays

“…5d). 111 By adjusting the stacked order of the RGB QD monolayers, the nonradiative energy transfer (e.g., G → R) was prevented, and true white EL could be achieved (Fig. 5e, f).…”

Inkjet-Printed CdTe Quantum Dots-Polyurethane Acrylate Thin Films

“…Therefore, QDs are also called "nanocrystals" and "artificial atoms." Recently, QDs have drawn extensive attention in various fields due to their unique opticalelectrical properties [4][5][6][7][8][9]. For example, the size-dependant emission spectra of QDs can be freely tuned in the visible range during the synthesis process and excited by the certain wavelength [4].…”

“…QDs-polymer composite materials with unique mechanical, electrical, optical, and thermal properties have been widely studied around the world [13,14]. These unique properties are related to a number of aspects such as the present status of QDs, the dispersion of QDs in the matrix, and the interaction between QDs and polymers [9,10,14]. Recently, UV curing resins are extensively used in the synthesis process of polymer nanocomposites which have the advantages of low-cost and energy efficient [15].…”

“…For example, the size-dependant emission spectra of QDs can be freely tuned in the visible range during the synthesis process and excited by the certain wavelength [4]. Because of the high quantum efficiency and excellent color purity, QDs are recognized as one of the most promising photoelectric display materials [9][10][11].…”

“…The new types of QDs displays possess high color purity and saturation which can remarkably improve the color quality of current display technology, especially for the flexible devices [9][10][11][12][13][14]. QDs-polymer composite materials with unique mechanical, electrical, optical, and thermal properties have been widely studied around the world [13,14].…”