Micron-Scale Patterning of High Quantum Yield Quantum Dot LEDs

Micron-scale resolution patterning of colloidal quantum dots (QDs) is demonstrated by adopting inkjet printing as a technique that is solvent and room temperature compatible, maintains optical and electronic properties of printed QD films, and results in minimal materials waste during the deposition process. With a combination of solvent engineering and substrate patterning single prints of PbS-CdS core-shell QDs (with peak photoluminescence emission at lambda = 1270 nm wavelength) are deployed to form QD films of nanoscale-thickness, with regular micron-scale patterns. Inkjet printing of infrared QD films is chosen as a case study for manufacture of QD-light emitting diodes (QD-LEDs), and demonstrates devices with a record peak external quantum efficiency in excess of 2% that is finally comparable with state-of-the-art spin-coated prototypes.