A new article from Ning Yan’s lab has been published in Chemical Engineering Journal written by Nicolas R. Tanguy, Maryam Moradpour, Mandeep C. Jain, Ning Yan, and Mohammad H. Zarifi.

The article can be accessed for free until June 13, 2023 by clicking here.

Abstract

The rapid development of electronics has caused the accumulation of electronic waste that is threatening the environment and human health. The deployment of the Internet of Things (IoT), enabled by 5G microwave communication technology, will involve an increasing number of electronic devices. Microwave communication devices consist of petroleum/ceramic-based substrates and metallic traces that are non-biodegradable. Here, we report a smart, flexible, and transient organic microwave resonator (TOMR) using cellulose nanofibrils (CNF) nanopaper as substrate and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as conducting trace. The device produced a resonant profile with the maximum transmission coefficient (S₂₁) amplitude of −14.95 dB at a resonant frequency of 2.75 GHz under ambient conditions (20 °C, 30% relative humidity (RH)). The TOMR demonstrated sensing capabilities, wherein increasing the %RH modulated the device’s resonant amplitude (-29 mdB/%RH from 0% to 50% RH and −90 mdB/%RH from 50% to 90% RH) and resonant frequency (3600 kHz/%RH). Moreover, the PEDOT:PSS trace could be reclaimed, recycled, and redeposited on a CNF nanopaper, which enabled the fabrication of a TOMR that displayed a similar resonant profile. Hence, this study demonstrates the first transient organic microwave resonator embedded with sensing capabilities and introduces a framework to minimize the environmental impact of 5G microwave communication devices for the IoT.