# Photoluminescence of 2D and 3D quantum dots synthesized by laser-ultrasonic treatment on van der Waals materials

## TL;DR

A new method for making quantum dots from van der Waals materials is shown to control their light emission across a wide range of colors.

## Contribution

A two-stage synthesis method for van der Waals quantum dots with controllable photoluminescence is introduced.

## Key findings

- Quantum dots made from MoS2, WS2, MoSe2, and WSe2 show pump-dependent visible-range photoluminescence.
- Laser-ultrasonic treatment produces both 2D and 3D quantum dots with broad size distributions.
- Photoluminescence can be tuned by adjusting the pump laser wavelength.

## Abstract

A two-stage method for synthesis of van der Waals quantum dots in a liquid by laser ablation of the initial material followed by ultrasonic treatment of the samples is proposed and implemented. The use of various initial samples in the form of pressed powder targets or transition metal dichalcogenide crystals allows the fabrication of both three-dimensional and flat few-layer quantum dots that are capable of exhibiting a photoluminescent response in a wide spectral range. The possibility of straightforward control of photoluminescence spectra in ensembles of MoS2, WS2, MoSe2, and WSe2 quantum dots with wide-size dispersions by tuning the pump laser wavelength is shown.

Ensembles of van der Waals quantum dots with a wide-size dispersion, fabricated by two-stage laser and ultrasonic treatment, exhibit the pump-dependent photoluminescence in the visible spectral range.