Eco-designed recycled newspaper for energy harvesting and pressure sensor applications

Abstract

This study focuses on developing multifunctional electronic paper (e-paper) using a low-cost recycling method to minimize the usage of critical raw materials. The e-paper is designed for various smart applications, such as mechano-responsive energy harvesters and pressure sensors. The emphasis is on adopting an eco-friendly approach by utilizing cellulose extracted from used newspapers, which would otherwise have been discarded. The formulated e-paper contains 100 % recycled cellulose fibers, unlike the more commonly used recycled paper, which contains around 70 % of recycled cellulose and 30 % of new pulp. The recycled paper (RP) was functionalized using polyaniline (PANi), resulting in a conductive e-paper, capable of generating electric current through a charge transfer mechanism at the PANi-Cellulose/electrode interface layer. The resulting devices demonstrate satisfactory energy production, with output voltage ranging from 16.8 to 20.25 V, output current ranging from 0.9 µA to 1.75 µA, and power density ranging from 0.18 to 0.35 Wm−2. The mechanical impulses generated by the device can successfully light up several LEDs in series. Additionally, the e-paper was investigated as a flexible, paper-based pressure sensor. The fabricated device exhibited excellent sensitivity, fast response time, and a wide detection range from 25 Pa to 12.25 kPa. The sensitivity of the pressure sensors achieved 4.21 kPa−1 within a low range of 0–1 kPa and approximately 0.008 kPa-1for a broader pressure range (2 – 12.25 kPa). Additionally, the durability of the pressure sensing devices has undergone rigorous testing, surpassing 2000 cyclic tests.