# Hot‐Injection‐Free Silicon Nanocrystals Realize Record‐Breaking Sustainable QD LEDs

## TL;DR

This paper introduces a sustainable method to produce high-performance silicon quantum dots for use in efficient and eco-friendly LED devices.

## Contribution

A hot-injection-free method for producing silicon quantum dots with record-breaking performance in LEDs is presented.

## Key findings

- SiQDs synthesized via the HSQ polymer route achieve photoluminescence quantum yields near 80%.
- SiQD LEDs show external quantum efficiencies over 16% and lifetimes over 700-fold increased.
- Rice husk-derived SiQDs demonstrate potential for low-waste circular material cycles.

## Abstract

Silicon quantum dots (SiQDs) are an emerging class of high‐performing, sustainable, environmentally safe luminescent nanomaterial. They offer opportunities for next‐generation displays, solid‐state lighting, medical applications, and quantum technologies. Here, we highlight recent breakthroughs in colloidal SiQD synthesis and photophysics, comparing eight synthetic strategies. Among these, we focus on the hydrogen silsesquioxane (HSQ) polymer route, a simple and cost‐effective hot‐injection‐free method that yields highly crystalline, ultrabright, and stable SiQDs with photoluminescence quantum yields approaching 80%. We also describe how solvent engineering realizes SiQD light‐emitting diodes (LEDs) with record external quantum efficiencies (EQEs, >16%), >700‐fold‐increased lifetimes, and far‐red emissions to rival state‐of‐the‐art perovskite QD LEDs. Moreover, rice husk‐derived SiQD LEDs illustrate the potential for low‐waste circular material cycles. Thus, SiQDs are a sustainable platform for plant growth technologies, photodynamic therapy, and beyond.

Silicon quantum dots are a safe and sustainable nanocrystal material that can be used in applications ranging from solar windows, upconversion, photodynamic therapy, and plant growth technologies. In our laboratory and others, recent advances have meant that the optical performance of these materials and the devices made from them has increased such that they are a viable alternative to toxic heavy‐metal‐containing quantum dot materials. Moreover, a materials cycle based on rice husk processing, producing efficient light‐emitting diode (LED) devices, has been demonstrated.© 2025 WILEY‐VCH GmbH