A toxicology-informed, safer by design approach for the fabrication of transparent electrodes based on silver nanowires

TL;DR

This study demonstrates a controlled fabrication process for silver nanowires with specific dimensions, evaluates their optoelectronic performance as transparent electrodes, and assesses their toxicity, promoting safer design choices.

Contribution

It introduces a method for precise control of silver nanowire dimensions and evaluates their performance and toxicity, supporting safer application in electronics.

Findings

Silver nanowires with controlled size were successfully fabricated.

Transparent electrodes with high performance were developed.

Shorter nanowires showed slightly higher toxicity but less prolonged inflammatory response.

Abstract

Fabrication of silver nanowires (AgNWs) with fine and independent control of both the diameter (from 30 to 120 nm) and length (from 5 to 120 $\mu$m) by concomitant addition of co-nucleants and temperature control is demonstrated, and used for the preparation of size standards. Percolating random networks were fabricated using these standards and their optoelectronic properties were measured and compared with regard to the nanowire dimensions. The transparent electrodes appear suitable for various applications and exhibit excellent performances (e.g. 16 ohm sq --1 at 93% transparency), with haze values varying from 1.6 to 26.2%. Besides, in vitro toxicological studies carried out on murine macrophages with the same size standards revealed that AgNWs are weakly toxic (no toxicity observed below 50 $\mu$g mL --1 Ag), in particular compared to other silver nanoparticles. Short AgNWs (4 $\mu$m) appeared to be slightly more toxic than longer AgNWs (10 and 20 $\mu$m). Conversely, long AgNWs (20 $\mu$m) induced a more prolonged pro-inflammatory response in murine macrophages. These results contribute, in a safer by design approach, to promoting the use of short AgNWs. The global knowledge dealing with the combination of nanowire dimensions associated with optoelectronic performances and related toxicity should encourage the rational use of AgNWs, and guide the choice of the most adequate AgNW dimensions in an integrated approach.