Projection lithography patterned high-resolution quantum dots/thiol-ene photo-polymer pixels for color down conversion

Abstract

Pixelated color converters are envisioned to achieve full-color high-resolution display through down conversion of blue/ultraviolet(UV) micro-LEDs. Quantum dots (QDs) are promising narrow-band converters of high quantum efficiency and brightness enabling saturated colors with wide color gamut in displays. Here we demonstrate high-resolution pixelated red and green QDs/thiol-ene photo-polymer converters (single pixel down to 6 µm; converters array of 21 µm pixel, 30 µm pitch and sub 10 µm thickness) patterned through projection lithography. QDs capped with amine surface group are uniformly dispersed in thiol-ene photo-polymer matrix at high concentrations (up to 100 mg/mL), which reduces aggregation and improves conversion efficiency by 0.5-1 times compared to drop-cast QDs. Color cross-talk is also reduced through patterning light blocking walls between converter pixels.