Advances and Challenges in Heavy-Metal-Free InP Quantum Dot Light-Emitting Diodes

Light-emitting diodes based on colloidal quantum dots (QLEDs) show a good prospect in commercial application due to their narrow spectral linewidths, wide color range, excellent luminance efficiency, and long operating lifetime. However, the toxicity of heavy-metal elements, such as Cd-based QLEDs or Pb-based perovskite QLEDs, with excellent performance, will inevitably pose a serious threat to people's health and the environment. Among heavy-metal-free materials, InP quantum dots (QDs) have been paid special attention, because of their wide emission, which can, in principle, be tuned throughout the whole visible and near-infrared range by changing their size, and InP QDs are generally regarded as one of the most promising materials for heavy-metal-free QLEDs for the next generation displays and solid-state lighting. In this review, the great progress of QLEDs, based on the fundamental structure and photophysical properties of InP QDs, is illustrated systematically. In addition, the remarkable achievements of QLEDs, based on their modification of materials, such as ligands exchange of InP QDs, and the optimization of the charge transport layer, are summarized. Finally, an outlook is shown about the challenge faced by QLED, as well as possible pathway to enhancing the device performance. This review provides an overview of the recent developments of InP QLED applications and outlines the challenges for achieving the high-performance devices.

Automated summary

Light-emitting diodes based on colloidal quantum dots (QLEDs) have good prospects in commercial applications, but the toxicity of heavy-metal elements in QLEDs poses a serious threat to health and the environment. InP quantum dots (QDs), as heavy-metal-free materials, are widely regarded as one of the most promising materials for next-generation displays and solid-state lighting. This review systematically illustrates the progress of QLEDs based on InP QDs, including their fundamental structure and photophysical properties. It also summarizes the achievements of QLEDs through materials modification and charge transport layer optimization. The review provides an overview of recent developments and outlines the challenges for achieving high-performance InP QLED devices.