Efficient and Pure I-III-VI AIGS Quantum Dot-Based Light-Emitting Diodes via Ligand-Reshaped Surface State

The I-III-VI silver indium gallium sulfide (AIGS) quantum dots (QDs) have gained extensive attention owing to their tunable emission wavelength and ecofriendly composition; however, the performance of AIGS QD-based light-emitting diodes (QLEDs) remains constrained by suboptimal surface state, significantly lagging behind that of other heavy-metal-containing QD counterparts. Herein, we propose a ligand-reshaped strategy aimed at optimizing the surface state of AIGS QDs to enhance the performance of QLEDs. A polyfunctional ligand, dimercaptosuccinic acid (DSA), is introduced to reshape the QD surface through passivation of uncoordinated Ga³⁺ and suppression of S vacancies. After DSA passivation, the QDs exhibit not only exceptional luminescent properties with a photoluminescence quantum yield of 89%, but also pure emission with a narrow full width at half maximum of 31 nm. Concurrently, DSA passivation markedly improves the electrical transport characteristic of QDs, thereby ensuring efficient carrier injection. Resultantly, the reshaped QLED achieves a maximum peak external quantum efficiency of 8.4% along with a narrow FWHM of 31 nm, representing a record performance reported thus far for the AIGS system. The proposed DSA ligand-reshaped strategy endows AIGS QLEDs with both high efficiency and color purity, substantially advancing their potential for the application in QD lightings and display technologies .