Nature Degradable, Flexible, and Transparent Conductive Substrates from Green and Earth-Abundant Materials

The rapid development of wearable and disposable electronic devices and the rising awareness of environmental sustainability impose growing new demands on the nature degradability of current electronic and energy systems. Here we report a new type of flexible transparent conductive paper completely made from green and earth abundant materials which are also fully degradable and recyclable. Aluminum-doped zinc oxide (AZO) was deposited by low-temperature atomic layer deposition (ALD) as the transparent conductive oxide (TCO) layer on transparent cellulose nanofibril (CNF) papers. The mesoporous structure of the CNF paper rendered strong adhesion of the AZO layer and exhibited excellent mechanical integrity and electrical conductivity within a wide range of tensile and compressive strains. The AZO-CNF paper could be completely dissolved in warm city water after one-hour stirring, demonstrating an excellent nature degradability. A flexible and transparent triboelectric nanogenerator (TENG) was further fabricated using such AZO-CNF papers with a performance that was comparable to other synthetic polymer-based systems. This work illustrated a new and promising strategy of utilizing 100% green and degradable materials in novel electronic and energy harvesting devices.