Fig. 1. Photolithographic realization of quantum dot patterning. (a) Schematic of the basic photolithography process^[28]; (b) schematic of the sacrificial layer assisted pattern formation method (SLAP) process^[29]

Fig. 2. Direct lithography realizing quantum dot patterning. (a) Schematic diagram of direct lithography utilizing a photo acidic initiator (PAG) to undergo ligand exchange with ligands on the surface of quantum dots^[31]; (b) schematic of the principle of photo crosslinking^[33]; (c) photo crosslinking patterning process flow^[33]; (d) direct photolithography process of chalcogenide quantum dots with ligand crosslinker^[34]; (e) current efficiency-current density curves and external quantum efficiency-brightness curves of optical crosslink-patterned chalcogenide devices^[34]

Fig. 3. Inkjet printing quantum dots patterning related research. (a) Schematic diagram of the principle of inkjet printing and the formation process of coffee rings^[43]; (b) electroluminescence morphology as well as current density-voltage-brightness curves and current efficiency-current density curves of quantum dot patterned devices prepared by solvent printing with a mixture of decane and cyclohexylbenzene (CHB)^[46]; (c) morphology of quantum dot pixel array prepared using octane and cyclohexylbenzene mixture ink^[47] (scale bar: 50 μm); (d) 500 pixel/inch two-color pattern array prepared using electrohydrodynamic (EHD) printing^[48]; (e) EHD printing process and electroluminescence morphology of a patterned device with a Teflon barrier layer^[49]

Fig. 4. Transfer printing patterning process. (a) Schematic of the process of solvent-free transfer printing^[56]; (b) process flow for the introduction of an eliminable polymer layer to achieve complete transfer of a single polymer layer of quantum dots^[57]; (c) schematic of the gravure transfer printing process^[58]

Fig. 5. Quantum dot/zinc oxide double-layer transfer process^[61]. (a) Process flow diagram; (b) a sample of monochromatic photoluminescence; (c) full-color photoluminescent array; (d) structure and luminescence morphology of the electroluminescent device

Fig. 6. Self-assembly patterning process. (a) Building patterned arrays by asymmetric wettability^[63]; (b) immersion transfer printing process flow^[64]; (c) quantum dot electrophoretic deposition process^[65]

Fig. 7. Self-assembly patterning process. (a) Process flow for high-resolution patterning using Langmuir‒Blodgett technique combined with transfer printing^[66]; (b) schematic of the process of electrostatic-induced deposition quantum dot patterning and luminescence morphology of the device^[67]

Fig. 8. Femtosecond laser direct writing technology patterning process. (a) Femtosecond laser direct writing process^[68]; (b) femtosecond laser construction schematic and morphology of patterned quantum dot arrays^[70]

Fig. 9. Full-color patterning schematic of optical microcavity and the device structure^[77]

Fig. 10. Multi-functional tandem LED^[82]. (a) Multi-functional tandem LED structure and driving method; (b) full-color LED driving mechanism and CIE coordinate range

Fig. 11. Schematic diagram of the anti-staining (avoiding cross-contamination of multicolor quantum dots) strategy^[83]

Fig. 12. High-resolution pixel optical crosstalk suppression strategy^[84]. (a) Simplified schematic of bottom-emitting high-resolution red quantum dot light-emitting diode array model; (b) electroluminescent pictures of a pixel array device without optical crosstalk

Fig. 13. Localized surface plasmon resonance (LSPR) effect to enhance high-resolution device performance^[85]. (a) Schematic of LSPR effect for quantum dot devices; (b) high-resolution array luminescence pattern; (c) external quantum efficiency and lifetime curves of the device

Fig. 14. Structure and luminescence morphology of LE-MOSJ arrays^[86]. (a) Structure of LE-MOSJ array; (b) electroluminescent image of LE-MOSJ array at 50 V and 100 kHz

Fig. 15. Patterned molybdenum trioxide hole transport layer process flow and structure and electrical characteristics of the device^[87]. (a) Molybdenum trioxide direct lithography process; (b) structure and external quantum efficiency-current density curves of the QLED device and electroluminescent array pattern with a pixel size of 5 μm

Fig. 16. Performance of QLED active matrix displays^[89]. (a) Schematic of the driving TFT structure; (b) light-emitting images of active matrix QLED; (c) external quantum efficiency and current efficiency curves

Fig. 17. Quantum dot micro-display prototype^[90]. (a) QLED micro display chip; (b)‒(d) electroluminescent images