Thermodynamic-driven polychromatic quantum dot patterning for light-emitting diodes beyond eye-limiting resolution

Abstract

The next-generation wearable near-eye displays inevitably require extremely high pixel density due to significant decrease in the viewing distance. For such denser and smaller pixel arrays, the emissive material must exhibit wider colour gamut so that each of the vast pixels maintains the colour accuracy. Electroluminescent quantum dot light-emitting diodes are promising candidates for such application owing to their highly saturated colour gamuts and other excellent optoelectronic properties. However, previously reported quantum dot patterning technologies have limitations in demonstrating full-colour pixel arrays with sub-micron feature size, high fidelity, and high post-patterning device performance. Here, we show thermodynamic-driven immersion transfer-printing, which enables patterning and printing of quantum dot arrays in omni-resolution scale; quantum dot arrays from single-particle resolution to the entire film can be fabricated on diverse surfaces. Red-green-blue quantum dot arrays with unprecedented resolutions up to 368 pixels per degree is demonstrated.

High-Resolution Colloidal Quantum Dot Film Photolithography via Atomic Layer Deposition of ZnO

“…QDs can be patterned via inkjet printing, but nozzles can get clogged after many cycles of operation which limits the high resolution due to fluid aggregation resulting from surface energy. − Electrohydrodynamic (EHD) printing can provide precise patterns with the aid of a high electric field between the substrate and nozzle, , but the EHD method for QD display is still limited in terms of throughput and tact time for industrial applications. The transfer printing method has been extensively studied; however, the transfer process significantly depends on kinetic parameters such as stamp–substrate adhesion energy and applied pressure. − …”

Template Dissolution Interfacial Patterning of Single Colloids for Nanoelectrochemistry and Nanosensing

“…21 To print the assembled NPs we used immersion transfer printing. 35 This printing technique is based on an adhesion switching mechanism that considers the interaction energies at the interface between each individual component involved in the assembly and transfer of NPs. First, the PI tape is manually pressed onto a receiver substrate to bring the NPs in direct contact with the substrate surface.…”

“…The formation of AZ hinders Brownian motion and diffusivity of the NPs in solution, thereby ensuring that particles remain trapped at the desired site for deposition . To print the assembled NPs we used immersion transfer printing . This printing technique is based on an adhesion switching mechanism that considers the interaction energies at the interface between each individual component involved in the assembly and transfer of NPs.…”

“…TDIP can be a versatile tool for patterning a large assortment of colloids in terms of size and shape. Provided the previous demonstration in printing 3–6 nm diameter quantum dots (albeit a different assembly approach), we expect the technique to be feasible for sub-10 nm particles if assembly templates can be designed accordingly. In terms of particle geometry, TDIP can be extended to any non-spherical NPs obtainable through wet chemical synthesis and also potentially to non-metallic, micrometer-scale colloids. − As an example for non-spherical NPs, Figure S3 shows an array of printed nanocubes.…”

How Will Quantum Dots Enable Next‐Gen Display Technologies?

“…Multiple variations of this principle successfully have been applied to demonstrate monochrome and full-color QD patterning with a resolution that's always improving. [16][17][18][19] However, there appears to be a limitation in the display size as a result of this technique, because of the stamps' size.…”