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Solution‐processed ternary‐compound semiconductor AgBiS2 colloidal quantum dots (CQDs) are promising light‐absorbing materials owing to their nontoxicity and high absorption coefficient (>106 cm−1). However, rational strategies to passivate multi‐facet of ternary‐compound CQDs and manufacture stable CQD inks have not yet been proposed. In this paper, a ligand passivation strategy is proposed using a solution‐phase ligand exchange method. A quadruple‐ligand ensemble is employed to demonstrate multifaceted passivation on AgBiS2 CQDs and a highly stable CQD ink. Density functional theory studies reveal the secondary cation adsorption of silver halide passivation, indicating the synergistic passivation of the ligand ensemble. This yields a low trap density in CQD solids, improving the power conversion efficiency to 8.1% by 53% in CQD solar cells. Furthermore, the proposed device exhibits the fastest response time of 400 ns among all reported AgBiS2 devices, demonstrating its potential for efficient lead‐free optoelectronics. [ABSTRACT FROM AUTHOR]

The fabrication of heterostructures via solution process is one of the essential technologies for realizing efficient advanced-generation optoelectronics. Hybrid structures comprising colloidal quantum dots (CQD) and organic semiconducting molecules are garnering considerable research interest because of their complementing optical and electrical properties. However, blending both the materials and forming a stable electronic ink are a challenge owing to the solubility mismatch. Herein, a CQD:organic ternary-blended hybrid solar ink is devised, and efficient hybrid solar cells are demonstrated via single-step spin coating under ambient conditions. Specifically, the passivation of the benzoic acid ligand on the CQD surface enables the dissolution in low-polar solvent such as chlorobenzene, which yields a stable CQD:organic hybrid ink. The hybrid ink facilitates the formation of favorable thin-film morphologies and, consequently, improves the charge extraction efficiency of the solar cells. The resulting hybrid solar cells exhibit a power conversion efficiency of 15.24% that is the highest performance among all existing air-processed CQD:organic hybrid solar cells. [ABSTRACT FROM AUTHOR]