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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]

Although post‐synthetic anion exchange allows halide perovskite quantum dots to easily change the optical bandgap of materials, additional exchange of shorter ligands is required to use them as active materials in optoelectronic devices. In this study, a novel all‐in‐one process exchanging ligands and halide anions in film‐state for facile color tuning and patterning of cesium lead halide perovskite colloidal quantum dot (PeQD) light‐emitting diodes (LEDs) is proposed. The proposed all‐in‐one process significantly enhances the performances of PeQD LEDs by passivating the PeQD with shorter ligands. In addition, the all‐in‐one process is repeated more stably in the film state. Red, green, and blue LEDs with extremely narrow emission spectra using cesium lead bromide PeQDs and appropriate butylammonium halide solutions are fabricated. Furthermore, the proposed all‐in‐one process in film‐state facilitated rapid color change in localized areas, thereby aiding in realizing fine patterns of narrow widths (300 µm) using simple contact masks. Consequently, various paint‐over red/green/blue patterns in PeQD LEDs by applying halide solutions additively are fabricated. [ABSTRACT FROM AUTHOR]

Emerging semiconducting materials including colloidal quantum dots (CQDs) and organic molecules have unique photovoltaic properties, and their hybridization can result in synergistic effects for high performance. For realizing the full potential of CQD/organic hybrid devices, controlling interfacial properties between the CQD and organic matter is crucial. Here, the electronic band between the CQD and the polymer layers is carefully modulated by inserting an interfacial layer treated with several types of ligands. The interfacial layer provides a cascading conduction band offset (ΔEC), and reduces local charge accumulation at CQD/polymer interfaces, thereby suppressing bimolecular recombination; a thin thiol‐treated interfacial layer (≈6 nm) decreases shallow traps, resulting in higher short‐circuit current (JSC) and fill factor of hybrid solar cells. Based on these results, a high performance CQD/polymer hybrid solar cell is introduced that demonstrates a power conversion efficiency of 13.74% under AM 1.5 solar illumination. The hybrid device retains more than 90% of its initial performance after 402 days under ambient conditions. [ABSTRACT FROM AUTHOR]

Surface-tailored ZnO nanoparticles were successfully prepared by a modified synthetic route and enables CQD:ZnO hybrid ink. Ink-process without any post-deposition process resulted in favorable heterogeneous morphology and achieved broadband photon energy conversion across visible to near-infrared. [Display omitted] • A new synthetic route successfully tailors the surface properties of ZnO NPs. • Phosphonic acid-terminated NPs successfully enable to control the surface polarity. • The stable mixed heterogenous nanocrystal ink, comprising CQD and ZnO NPs, is demonstrated. • Simple ink-process without any post-deposition process results in favorable heterogeneous morphology and shows broadband photon energy conversion across 350–1100 nm. Blending multiple functional nanoparticles (NPs) into one solvent and forming a stable hetero-ink is a promising technology to realize efficient solution-processed heterogeneous structures for next-generation energy conversion. However, differences in the surface nature of NPs hinder the formation of stable hybrid ink, causing unfavorable morphologies in film formation. In this work, we demonstrate a stable hybrid ink using colloidal quantum dots (CQDs) and metal-oxide NPs. The modified synthesis route of ZnO NPs enables modulation of their surfaces, resulting in ink that is fully miscible in alkyl amine solvents with CQDs. This hybrid ink allows the formation of conformal heterogeneous thin-films via a single step spin-casting. Based on this result, we devise an efficient planar-mixed heterojunction solar cell, which exhibits a 12.8% power conversion efficiency (PCE), one of the highest performances among prior CQD:metal-oxide hetero-structured hybrid solar cells. [ABSTRACT FROM AUTHOR]