Direct In Situ Cascade Photolithography of Perovskite Quantum Dot Patterns with High Light Conversion Efficiency and Enhanced Stability

Quantum dots (QDs) characterized by high absorption coefficients and elevated photoluminescence quantum yields have facilitated the development of micro-light-emitting diodes (Micro-LEDs) employing QD-based color conversion techniques. This methodology has shown considerable potential for the realization of full-color near-eye microdisplay devices. However, significant challenges persist, notably the pronounced leakage of blue light and the limited operational stability of these systems. In this study, we present the fabrication of perovskite quantum dot (PQD) patterns exhibiting high light conversion efficiency (LCE) and enhanced photostability by the incorporation of cascade curing within the direct in situ photolithography process. The pattern was generated through a thiol-ene click reaction initiated by UV exposure, followed by the formation of PQDs during the development stage, subsequent thermal cross-linking of the epoxy-amine system during postbaking further enhanced the stability of the PQDs. Using direct in situ cascade photolithography, colorful PQD patterns with a resolution of 10 μm, excellent fluorescence uniformity, and robust stability are successfully demonstrated. Furthermore, our findings suggest that the in situ cascade photolithography technique facilitates the generation of an increased number of nuclei from the perovskite precursor, thereby yielding a higher concentration of PQDs. This enhancement results in an impressive 99% absorption of blue light and an exceptionally high LCE of 38% within a 3.9 μm-thick film. Additionally, the PQDs maintain over 80% of their initial LCE after prolonged exposure of 100 h to continuous blue light irradiation at an intensity of 11 mW/cm². This approach represents a significant advancement in the domain of direct photolithography and holds considerable promise for its integration into diverse optoelectronic devices.