Plant‐Based Substrate Materials for Flexible Green Electronics

Abstract

With the increasing use of soft and flexible electronics, there is a growing need to develop substrate materials that mitigate potential environmental risks associated with non‐degradable electronics waste from synthetic substrate materials. To address this issue, the authors develop a novel, 2D plant‐based substrate termed “sporosubstrate”, which is made of non‐allergenic natural pollen. The pollen particle has a double‐layered architecture with an ultra‐tough sporopollenin exine, and a soft cellulose intine is engineered through an eco‐friendly process. In this manner, a readily available, economical, biodegradable, and biocompatible microgel can be prepared. This microgel can be used to create a variety of flexible shapes with customized mechanical, geometrical, electronic, and functional properties and performance characteristics such as thermal, chemical, and mechanical stability and optical transparency. Moreover, the authors demonstrate here different applications of the flexible natural substrate made of pollen microgel for use in electronic devices for health monitoring and wearable wireless heating. The results of this work point to opportunities for the development of a new class of flexible green electronics based on plant‐based materials in applications such as wearable sensors, implantable devices, and soft robotics.

Extraordinary microcarriers derived from spores and pollens

“…Huang et al used pollen microgel as substrates, in which they attached electrodes and heat patches by laser cutting, ink writing and transfer printing. 114 Resultantly, they successfully constructed skin-mountable and stretchable biosensors and heating devices and demonstrated the feasibility of pollen substrates for flexible electronics (Fig. 12a).…”

“…However, the inherent mechanical properties and non-biocompatibility greatly restricted these materials' promotion. 114,115 In contrast, pollen has a special elastic structure and is non-toxic, low cost, and low weight, allowing for a variety of curved dynamic interfaces and mass manufacturing. Moreover, its biocompatible characteristics can reduce the discomfort of long-term use on the human body.…”

“…118 Compared to conventional photovoltaic substrates, the pollen material can achieve versatile and tunable functional properties without complex processing, which makes it an excellent candidate for new environmentally friendly photovoltaic device components. 114 Copyright 2022, Advanced Materials Technologies. (b) Scheme of the process for testing the gate effect for biodetectors.…”

“…(a) Schematic diagram of the biosensors built on the matrix, and photograph of the Joule heating device on the pollen substrate. Reproduced with permission 114. Copyright 2022, Advanced Materials Technologies.…”

Green Flexible Electronics: Natural Materials, Fabrication, and Applications

“…Natural materials and their derivatives, including fibroin and silk, [25][26][27] wood and paper, [28][29][30] plants, [31][32][33][34] and biomass, [35][36][37][38] have attracted widespread attention owing to their advantages of no toxicity, low cost, abundance, and excellent biocompatibility. Owing to their abundant functional groups and hierarchical structures, natural materials can be functionalized using diverse manufacturing techniques to satisfy different requirements of mechanical, electrical, optical, and thermal properties in specialized applications (Scheme 1).…”