# Colloidal synthesis of large near-bulk InAs quantum dots through seeded and seedless growth using cluster precursors

## TL;DR

Researchers developed a new method to make large, environmentally friendly InAs quantum dots suitable for infrared technologies.

## Contribution

A colloidal synthesis method for large, RoHS-compliant InAs quantum dots using cluster precursors is introduced.

## Key findings

- Large InAs quantum dots with diameters up to 40 nm were synthesized using cluster precursors.
- The method uses 'green' commercial precursors compliant with EU RoHS directives.
- This approach enables infrared-active quantum dots suitable for telecommunications and bioimaging.

## Abstract

Quantum dots are high-potential materials for a wide range of applications, particularly in the infrared spectral range, including telecommunications, security, sensing, photovoltaics, and bioimaging. The size and chemical composition of semiconductor quantum dots determine their optoelectronic properties. While II-VI and IV-VI quantum dots are well-studied, the colloidal synthesis of infrared-active III-V quantum dots such as InAs, which are compliant with the European Union directive for restriction of hazardous substances, remains underdeveloped. In particular, the synthesis of larger InAs quantum dots is challenging due to the strong covalent character of In–As bonding, limited control over precursor reactivity, and complex growth pathways. Here we show the synthesis of large, near-bulk InAs quantum dots using atomic clusters as precursors. All nanostructures are synthesized from ‘green’ commercially available precursors. These results extend the accessible size regime of colloidal InAs nanoparticles to diameters approaching 40 nm and establish a platform for their use in infrared technologies.

Colloidal quantum dots are promising, low-cost materials for infrared technologies, but rarely comply with the EU directive on the restriction of the use of certain hazardous substances (RoHS). Here, the authors present the synthesis of large, near-bulk RoHS-compliant quantum dots, operating deep in the infrared.