Towards Low-Toxic Colloidal Quantum Dots

Colloidal quantum dots (CQDs) are of enormous interest in the scientific and engineering fields. During the past few decades, significant efforts have been conducted in investigating Cd- and Pb-based CQDs, resulting in excellent photoluminescence (PL) properties and impressive performance in various applications. But the high toxicity of Cd and Pb elements pushed the scientific community to explore low-toxic CQDs excluding poisonous heavy metals. Several semiconductor materials with lower toxicity than Cd and Pb species have been proposed. This article presents a short overview of recent efforts involving low-toxic CQDs, focusing especially on IV-VI and III-V semiconductors which are active in the near- and short-wave-infrared (IR) regimes. Recent achievements pertinent to Sn- and In-based CQDs are highlighted as representative examples. Finally, limitations and future challenges are discussed in the review.