Fig. 1. PQD-based Micro-LEDs full-color technology and stability solution^[23]. (a) Ligand exchange^[24]; (b) Ion doping^[25]; (c) Surface coating^[26]; (d) Chemical cross-linking^[27]

Fig. 2. (a) Schematic of a typical ABX₃ crystal structure of halide perovskite^[33] ; (b) Possible pathways for phase transitions of CsPbI₃^[39] ; (c) Photo-oxidation mechanism of CsPbI₃^[43]; (d) Schematic of the interaction between water and PNCs^[47]; (e) Schematic of photo-induced agglomeration of CsPbBr₃^[45]

Fig. 3. (a) Structure of CsPbI₃-DDAB and CsPbI₃-OA/OLA^[52]; (b) PLQY stability of CsPbI₃-DDAB and CsPbI₃-OA/OLA^[52]; (c) TEM image of CsPbI₃-DDAB after 60 days of storage in a dark environment^[52]; (d) Strategy of HI-induced in situ exchange strategy of 5AVA ligand with OA/OLA ligand^[54]; (e) Schematic of the passivation of amphipathic ionic ligands (sulfobetaine, phosphocholine and γ-aminoacids)^[58]; (f) DDAB and DLPS dual ligand passivation strategies^[59]; (g) PL stability of three QDs in natural environments^[59]

Fig. 4. (a) Schematic diagram of in-situ synthesized Ni²⁺ doped CsPbI₃ PQD^[75]; (b) Variation of PLQY with storage time for undoped and Ni-doped CsPbI₃ PQD^[75]; (c) Stabilization mechanism of Zn²⁺ doped CsMnCl₃ PQD^[77]; (d) PLQY at different Zn/Mn mass ratios^[77]; (e) Process flowchart for the preparation of CsPbBr₃ PQDs doped with NdCl₃^[79]; (f) PLQY stability of CsPbBr₃ PQDs with different dopants in a natural environment^[79]

Fig. 5. (a) Schematic structure of CsPbBr₃/LLPDE^[83]; (b) Degradation of CsPbBr₃ and CsPbBr₃/LLPDE in natural environment^[83]; (c) Degradation of CsPbBr₃ and CsPbBr₃/LLPDE under 365 nm light irradiation^[83]; (d) Flowchart for preparation of polymerisable CsPbX₃ PQD ink^[87]; (e) Ligand exchange and ALD-Al₂O₃ encapsulation flowchart^[97]; (f) CsPbBr₃/CdS and CsPbBr₃/Cs₄PbBr₆ encapsulation methods and energy maps^[103]; (g) Degradation of various QD materials in aqueous environment (left) and 365 nm light environment (right)^[103]

Fig. 6. (a) Schematic diagram of the preparation of CsPbBr₃ perovskite PQD in LHD nanosheets^[107]; (b) PL stability of CsPbBr₃ and LDH-CP-CsPbBr₃ at high temperatures^[107]; (c) Schematic diagram of in-situ growth of CsPbBr₃ QDs on hydrophobic silica aerogel^[108]; (d) PL stability of PQDs after heating at high temperatures for 1 hour^[108]; (e) Design schematic of CsPbBr₃ PQD composite materials^[109]; (f) Fluorescence characteristics of CsPbBr₃ PQD composite materials during heating-cooling cycles^[109]; (g) PL stability of PQDs with the addition of ethyl cellulose in a natural environment^[110]

Fig. 7. (a) Schematic diagram of PQD thin film preparation using photolithographic masking method^[113]; (b) PQD array with feature sizes as small as 3 µm^[113]; (c) Schematic diagram of PQD thin film preparation using photolithographic peeling method^[114]; (d) PQD dot array with a radius size of 5 µm^[114]; (e) Schematic diagram of in-situ fabrication of PQD patterns using lead bromide complex^[115]; (f) PQD fluorescence array with a resolution of up to 2450 PPI ^[115]; (g) Photopatterning mechanism of PZ ligands^[116]; (h) High-resolution PQD pattern with a line spacing of 4 µm^[116]

Fig. 8. (a) Reaction mechanism between PTMP and PQD (top) and schematic diagram of direct photolithographic fabrication of PQD patterns (bottom)^[119]; (b) PQD fluorescence array with a resolution of 12700 PPI^[119]; (c) Schematic diagram of PQD fluorescence array prepared by microsphere filling method^[120]; (d) High-resolution PQD fluorescence array with pixel size of 2 µm^[120]; (e) High-resolution dual-color PQD pattern^[120].

Fig. 9. (a) Schematic diagram of PQD color conversion layer prepared by aerosol inkjet printing technique^[125]; (b) PQD pattern with a line width of 13 µm ^[125]; (c) Schematic diagram of EHD inkjet printing^[126]; (d) PQD pattern with a resolution of 10 µm ^[126]; (e) Red PQD fluorescence array with a resolution of 2540 DPI ^[127]; (f) Full-color PQD color conversion layer with subpixel diameter of 10 µm ^[127]; (g) Schematic diagram of red PQD fluorescence array prepared by ligand exchange and EHD inkjet printing process^[127]

Fig. 10. (a) Schematic diagram of ink preparation and printing^[129]; (b) PQD fluorescence array with a resolution of up to 22718 DPI^[129]; (c) Fabrication process of mixed QD nanoring Micro-LED with line width less than 2 µm^[130]; (d) QD pattern with a line width of 1.65 µm^[130]; (e) Patterns of perovskite dot arrays with diameters of 1 µm, 2 µm, and 3 µm^[131]