Scalable Synthesis of InAs Quantum Dots Mediated through Indium Redox Chemistry

Abstract

Next-generation optoelectronic applications centered in the near-infrared (NIR) and short-wave infrared (SWIR) wavelength regimes require high-quality materials. Among these materials, colloidal InAs quantum dots (QDs) stand out as an infrared-active candidate material for biological imaging, lighting, and sensing applications. Despite significant development of their optical properties, the synthesis of InAs QDs still routinely relies on hazardous, commercially unavailable precursors. Herein, we describe a straightforward single hot injection procedure revolving around In­(I)Cl as the key precursor. Acting as a simultaneous reducing agent and In source, In­(I)Cl smoothly reacts with a tris­(amino)­arsenic precursor to yield colloidal InAs quantitatively and at gram scale. Tuning the reaction temperature produces InAs cores with a first excitonic absorption feature in the range of 700–1400 nm. A dynamic disproportionation equilibrium between In­(I), In metal, and In­(III) opens up additional flexibility in precursor selection. CdSe shell growth on the produced cores enhances their optical properties, furnishing particles with center emission wavelengths between 1000 and 1500 nm and narrow photoluminescence full-width at half-maximum (FWHM) of about 120 meV throughout. The simplicity, scalability, and tunability of the disclosed precursor platform are anticipated to inspire further research on In-based colloidal QDs.

Acid–Base Mediated Ligand Exchange on Near-Infrared Absorbing, Indium-Based III–V Colloidal Quantum Dots

“…Research on InAs QDs was long hampered by synthetic limitations, with literature providing mostly methods based on the harsh precursor chemistry of alkylated (Si,Ge)-arsines. − More recently, synthetic pathways based on reacting indium chlorides with tris­(dimethylamino)­arsine in coordinating amine solvents and a reducing agent have been described. These approaches yield access to InAs QDs absorbing from 750 to 1450 nm − and hold promise for large scale QD production. Importantly, this new approach to form InAs QDs was inspired by initial studies on InP QD synthesis and has been extended to form InSb and III–V alloys such as In­(As,Sb). − …”

Ag2ZnSnS4–ZnS core–shell colloidal quantum dots: a near-infrared luminescent material based on environmentally friendly elements

“…Consequently, there is an increased effort towards the development of heavy metal-free RoHS compliant low-cost luminescence phosphors as an alternative. 6 As a result indium/gallium based III-V group QDs such as InAs, InSb, GaAs [7][8][9][10] and I-III-VI group QDs such as CuIn(S/Se) 2 , AgIn(Se/ Te) 2 [11][12][13][14] with NIR emission have attracted significant interest.…”

Latest Trends in Lateral Flow Immunoassay (LFIA) Detection Labels and Conjugation Process

“… Ginterseder et al (2020) obtained indium arsenide quantum dots by a synthetic method that does not require pyrophoric precursors. They used a simple hot injection method with the main precursor iodine monochloride (In(I)Cl), which also serves as a reducing agent in the synthesis.…”