Biodegradation of bio-sourced and synthetic organic electronic materials towards green organic electronics

Eduardo Di Mauro,Denis Rho,Clara Santato

doi:10.1038/s41467-021-23227-4

Eduardo Di Mauro, Denis Rho + Show 1 more

Open Access

https://doi.org/10.1038/s41467-021-23227-4

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Abstract

Ubiquitous use of electronic devices has led to an unprecedented increase in related waste as well as the worldwide depletion of reserves of key chemical elements required in their manufacturing. The use of biodegradable and abundant organic (carbon-based) electronic materials can contribute to alleviate the environmental impact of the electronic industry. The pigment eumelanin is a bio-sourced candidate for environmentally benign (green) organic electronics. The biodegradation of eumelanin extracted from cuttlefish ink is studied both at 25 °C (mesophilic conditions) and 58 °C (thermophilic conditions) following ASTM D5338 and comparatively evaluated with the biodegradation of two synthetic organic electronic materials, namely copper (II) phthalocyanine (Cu–Pc) and polyphenylene sulfide (PPS). Eumelanin biodegradation reaches 4.1% (25 °C) in 97 days and 37% (58 °C) in 98 days, and residual material is found to be without phytotoxic effects. The two synthetic materials, Cu–Pc and PPS, do not biodegrade; Cu–Pc brings about the inhibition of microbial respiration in the compost. PPS appears to be potentially phytotoxic. Finally, some considerations regarding the biodegradation test as well as the disambiguation of “biodegradability” and “bioresorbability” are highlighted.

Highlights

Ubiquitous use of electronic devices has led to an unprecedented increase in related waste as well as the worldwide depletion of reserves of key chemical elements required in their manufacturing
The scientific problem we address is the compostability of one bio-sourced and two conventional synthetic electronic ingredients, using the ASTM D533845 protocol under operating conditions typical of an industrial composting facility, i.e., thermophilic (58 °C) and aerobic conditions
Throughout the incubation period, the respiration activity of the compost microbiota was monitored by electrolytic respirometers, measuring the amount of O2 consumed

Summary

Introduction

Ubiquitous use of electronic devices has led to an unprecedented increase in related waste as well as the worldwide depletion of reserves of key chemical elements required in their manufacturing. The use of biodegradable and abundant organic (carbon-based) electronic materials can contribute to alleviate the environmental impact of the electronic industry. A promising route towards achieving sustainable (green) electronics is based on the use of abundant materials (including biomolecules extracted from biomass feedstock), novel production schemes involving non-toxic solvents, and eco-design of devices that includes biodegradation at end of life[2]. Organic electronics is based on molecules and polymers that feature electronic conjugation by means of alternating single and double carbon–carbon bonds[6] Organic electronic devices such as organic light-emitting diodes, photovoltaic cells, field-effect transistors, and sensors have been demonstrated[7,8]. Our vision is to develop eco-friendly organic electronic materials and devices with reduced environmental impact, designed and certified to be compostable at their end of life. The particle size of the material to be composted is another important parameter

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