Robust and ultralow-energy direct photolithography of quantum dots via dual-ligand passivated thiol-ene click chemistry

Abstract Direct photolithography of colloidal quantum dots (QDs) via photoinitiated thiol-ene click chemistry has emerged as an attractive approach for the fabrication of high-resolution QD-based displays, benefiting from its site-controlled and byproduct-free reaction pathway. Nevertheless, this approach remains constrained by limited colloidal stability and suboptimal optoelectronic performance, stemming from spontaneous ligand exchange and unfavorable reaction kinetics. To address these challenges, we introduce a dual-ligand passivation strategy that replacing native QD ligands with rationally designed alkenyl ligands with strong binding affinity and high reactivity. This strategy confers a 6-fold enhancement in the storage lifetime and a 15-fold improvement in photolithographic efficiency. These advances enable the direct photopatterning of QDs with an ultrahigh resolution exceeding 18,000 PPI (pixel size: 0.77 μm), at an ultralow-energy dose of 1 mJ/cm2. Furthermore, the fabricated light-emitting diode with the crosslinked dual-ligand passivated QD (DLP-QD) and nano-patterned DLP-QD achieved peak external quantum efficiencies of 21.17% and 15.67%, respectively, ranking among the state-of-the-art devices in this field. This work demonstrates the promise of robust and efficient thiol-ene click chemistry enabled by dual-ligand passivation for direct QD photolithography, paving the way for high-performance QD-based displays and advanced optoelectronic devices toward industrial applications.