Chemical route enables scalable III-V infrared quantum dot synthesis

May 18, 2026

Scientists esearchers mapped the metal-amide chemistry that controls heavy-pnictogen reduction, enabling reproducible and scalable III-V infrared quantum dots.

(Nanowerk News) Researchers at Sungkyunkwan University have identified the chemical route that governs how heavy-pnictogen precursors are reduced during the synthesis of III–V infrared semiconductor quantum dots. The work was led by Professor Sohee Jeong in collaboration with Professor Maksym V. Kovalenko’s group at ETH Zurich. The findings appear in the Journal of the American Chemical Society (“Metal–Amide Chemistry Enables Controlled Heavy-Pnictogen Reduction for Colloidal III–V Nanocrystal Synthesis”).

Key Findings

Infrared sensing now underpins everyday systems, from nighttime object recognition in autonomous vehicles to smart home devices. That has steadily increased demand for high-performance infrared semiconductor materials. III–V quantum dots such as indium arsenide and indium antimonide are attractive because they deliver strong infrared optical performance while avoiding lead and mercury. Until now, the absence of practical precursor systems for arsenic and antimony limited synthetic design and scale-up. Heavy pnictogens are the heavier elements in the nitrogen group of the periodic table, a group that includes arsenic and antimony. The Jeong team separated the activation of these heavy-pnictogen(III) precursors from the moment quantum dots form. By decoupling the two steps, the researchers could observe how the precursors are reduced and gain reactivity before any nanocrystals appear. Schematic illustration of the heavy-pnictogen reduction mechanism identified by the research team (top) and optical/electron microscopy characterization of synthesized III–V semiconductor nanocrystals, including InAs and InSb (bottom). (Image: Sungkyunkwan University) (click on image to enlarge) The central discovery concerns metal–amide species generated when metal–alkyl reagents react with primary amines. These complexes undergo a temperature-driven amide-to-imine oxidation, and through it they drive the reduction of the heavy-pnictogen precursors. By adjusting the reduction temperature and the metal-cation environment, the team could reach partially reduced precursor states well suited to building III–V nanocrystals. This shifts nanocrystal synthesis away from trial-and-error optimization toward a design strategy grounded in chemistry. Instead of combining all reactants at once and tuning conditions empirically, researchers can prepare precursors with controlled reactivity in advance and then use them for nanocrystal growth. The change gives much greater control over the process from its earliest stage. Applying the approach, the team synthesized indium arsenide and indium antimonide nanocrystals without adding separate reducing agents during the growth step. Because the pre-reduced precursors are compatible with multiple techniques, the synthesis works with heat-up, hot-injection, and continuous-injection methods. That flexibility matters for producing infrared semiconductor materials at the volumes industrial applications require. The press release contains no direct quotes, so none are reproduced here. The study systematically exposes a chemical mechanism that had remained hidden inside a complex semiconductor synthesis process, and it demonstrates how fundamental chemical principles can be used to guide the design of advanced materials rather than discovering working recipes by chance. By converting an empirical procedure into a defined precursor design principle, the research changes how heavy-pnictogen III–V materials can be approached. The result is a route to infrared semiconductors that are safer to make, more reproducible between batches, and practical to produce at scale for smart sensors, imaging systems, and optoelectronic devices.