Author(s):
Pinheiro, Tomás ; Rosa, André ; Ornelas, Cristina ; Coelho, João ; Fortunato, Elvira ; Marques, Ana C. ; Martins, Rodrigo
Date: 2023
Persistent ID: http://hdl.handle.net/10362/154943
Origin: Repositório Institucional da UNL
Project/scholarship:
info:eu-repo/grantAgreement/FCT/3599-PPCDT/2022.08597.PTDC/PT;
Subject(s): CO laser; Electrochemical sensors; Laser-induced graphene; Paper electronics; pH; Sustainable production; Chemistry (miscellaneous); Materials Science (miscellaneous); Materials Chemistry; SDG 12 - Responsible Consumption and Production
Description
Funding Information: This work is funded by National Funds through FCT I.P. , under the scope of projects UIDB/50025/2020–2023. Authors also acknowledge funding from project BEST , grant Nos. ALT20–03–0247-FEDER-113469 and LISBOA-01–0247-FEDER-113469 . J. C. acknowledges the Santander/NOVA2021 Collaborative Research Award—Graphene Smart Bandages for Diabetic Foot Ulcer Monitoring, Reference GSBDFULM. T. Pinheiro acknowledges funding from FCT I.P. through the PhD Grant DFA /BD/8606/2020 Publisher Copyright: © 2023
Laser-induced graphene (LIG) allows for the fabrication of cost-effective, flexible electrodes on a multitude of recyclable and sustainable substrates, for implementation within electrochemical biosensors. This work expands on current LIG research, by experimentally modeling the effects of several CO2 laser irradiation variables towards resulting conductive and electrochemical properties of paper-derived LIG. Instead of relying on the established paradigm of manipulating power and scan speed of the laser irradiation process for optimized outcomes, modeling of underlying laser operation principles for pulse modulation, regarding pulse repetition frequencies, pulse duration and defocus are presented as the key aspects dominating graphitization processes of materials. This approach shows that graphitization is dominated by appropriate pulse durations, dictating the time the substrate is exposed to each laser pulse, with laser fluence and irradiation defocus influencing the resulting conductive properties, with sheet resistances as low as 14 Ω sq−1. Similarly, fabrication settings controlled by these parameters have a direct influence on the properties of LIG-based electrochemical three-electrode cells, with optimized fabrication settings reaching electrochemically active surface area as high as 35 mm2 and heterogeneous electron transfer rates of 3.4 × 10−3 cm.s−1. As a proof-of-concept, the production of environmentally friendly, accessible, and biocompatible pH sensors is demonstrated, using two modification approaches, employing riboflavin and polyaniline as pH-sensitive elements.
