Reduction of Graphene Oxide by Laser Scribing in Different Atmospheres and Application in Humidity Sensing

Abstract

Laser scribing, by far proposed as a method for efficiently transforming graphene oxide into reduced graphene, has been employed, using a CW laser beam, to study the modifications of graphene oxide scribed under different controlled atmospheres, including air, N2, Ar, and a 95 : 5 (v/v) Ar/H2 mixture. We have found that laser scribing effects, including chemical composition, order degree, and electrical properties, strongly depend upon the atmosphere during the irradiation. The electrical properties of the various materials, obtained in different atmospheres, have been evaluated with respect to the sensing properties towards humidity, the materials produced in pure Argon yielding the highest sensitivity and the fastest response, while related Raman microspectroscopy measurements showed that both Ar and Ar-H2 mixture produce the highest order among the various samples. The results stress the importance and the potentialities of controlling the irradiation atmosphere in order to tune the composition and electrical properties of the laser-scribed graphene oxide materials.

Raman Spectroscopy Investigation of Graphene Oxide Reduction by Laser Scribing

“…In our previous work [17], we demonstrated that the scribing environment is a key factor in achieving high-quality RGO and that Argon-based atmospheres yield the best outcome in terms of similarity of RGO to pristine graphene. In this paper, we determine the best materials and processing conditions to achieve the best possible RGO quality by investigating parameters such as scribing speed, amount of material, and number of scribing passes.…”

Laser Synthesized Graphene and Its Applications

“…It was found that the highest ΔR/R (~10%) was given by rGO obtained in argon, with the lowest hysteresis. The system showed a response and recovery as fast as that of a commercial RH sensor, but it was only responsive between 0% and ~15% RH [52].…”

“…The system showed a detection limit around 6% RH and very fast response (2 s) and recovery (4 s) time [55]. RH response from rGO obtained under different controlled atmospheres (air, N2, Ar, Ar/H2) was also investigated [52]. It was found that the highest ΔR/R (~10%) was given by rGO obtained in argon, with the lowest hysteresis.…”

“…Sokolov et al irradiated GO films with 355 nm and 532 nm continuous laser in air and N 2 , and noted by Raman spectroscopy that irradiation in N 2 atmosphere yielded rGO with less disorder [51]. Further studies were expanded to other atmospheres such as Ar and argon/H 2 (95:5) using a 405 nm continuous laser source [52]. Here, it was found by Raman spectroscopy that while Ar atmosphere produces better rGO than N 2 , the results obtained in Ar/H 2 are the most promising due to the presence of 5% H 2 that makes the atmosphere slightly reducing and thus more suitable for GO reduction (Figure 4) [52].…”

“…Further studies were expanded to other atmospheres such as Ar and argon/H 2 (95:5) using a 405 nm continuous laser source [52]. Here, it was found by Raman spectroscopy that while Ar atmosphere produces better rGO than N 2 , the results obtained in Ar/H 2 are the most promising due to the presence of 5% H 2 that makes the atmosphere slightly reducing and thus more suitable for GO reduction (Figure 4) [52]. The Ar-based environments were subject to further investigation relative to the LS conditions.…”