High-performance quantum dots enabled by supplementary passivation using ethoxydiphenylphosphine

Abstract Colloidal quantum dots (QDs) are pivotal to next-generation optoelectronics due to their exceptional quantum confinement effects and solution-processability. However, the high density of surface dangling bonds and vacancy defects inherent in QDs remains a primary bottleneck, inducing non-radiative recombination and limiting device performance. While conventional X-, L-, and Z-type ligand passivation strategies have been developed, achieving a “defect-free” surface for high-performance applications remains challenging. In this work, we introduce ethoxydiphenylphosphine (EDPP) as a universal complementary passivation strategy. For atomic ligand-capped PbS QD systems, EDPP treatment significantly improves QD film quality, enabling solar cells to reach a state-of-the-art infrared power conversion efficiency of 1.50% (under 1100 nm filtering). Furthermore, EDPP-passivated PbS QD photodetectors exhibit a 71.3% reduction in dark current and a peak specific detectivity (D*) of 6.34 × 1012 Jones at 1300 nm. The versatility of EDPP is further validated across various long-chain QD architectures, including InP/ZnSe/ZnS, CdSe/ZnS, PbSe/PbS, and so on, where it boosts photoluminescence quantum yield (PLQY) by up to 55.3%. These findings demonstrate that EDPP is a robust tool for precise surface state modulation, paving the way for high-performance, industrial-grade QD optoelectronic applications.