Multifunctional Dithiol Crosslinking Additive Enables Highly Efficient and Stable Inkjet-Printed Perovskite Quantum Dot Light-Emitting Diodes.

Abstract

Inkjet printing provides a scalable, cost-effective approach for fabricating perovskite quantum dot light-emitting diodes (Pe-QLEDs), particularly suited for high-resolution display applications. However, challenges such as poor ink printability and limited stability of perovskite quantum dots (Pe-QD) inks have impeded its widespread adoption. To overcome these limitations, 1,4-bis(3-mercaptobutyryloxy)butane (BD1), a dithiol-based cross-linkable additive is introduced to enable high-performance inkjet-printed Pe-QLEDs. BD1 serves three critical functions: i) it optimizes the rheological properties of the ink, promoting uniform droplet formation and adaptable inkjet printing process; ii) its thiol groups coordinate with under-coordinated Pb²⁺ sites on the QD surface, mitigating ligand loss during ink formulation and deposition, thus reducing defect density and enhancing optical quality; and iii) it participates in a thiol-ene click reaction with oleic acid ligands, forming robust crosslinked networks that improve film integrity and device stability. By leveraging these synergistic effects, BD1-enabled Pe-QLEDs achieve a record-high external quantum efficiency (EQE) of 21.73%, a peak luminance of 30,637.82 cd m^- ², and an enhanced operational lifetime. This additive engineering strategy also demonstrates versatility across red and blue Pe-QLEDs, highlighting its broad applicability. Collectively, the findings position BD1 as a highly effective multifunctional additive for stabilizing and optimizing Pe-QD inks, paving the way for scalable production of high-resolution, full-color Pe-QLED displays and other printed optoelectronic devices.