High Performance Three‐Dimensional Chemical Sensor Platform Using Reduced Graphene Oxide Formed on High Aspect‐Ratio Micro‐Pillars

Abstract

The sensing performance of chemical sensors can be achieved not only by modification or hybridization of sensing materials but also through new design in device geometry. The performance of a chemical sensing device can be enhenced from a simple three‐dimensional (3D) chemiresistor‐based gas sensor platform with an increased surface area by forming networked, self‐assembled reduced graphene oxide (R‐GO) nanosheets on 3D SU8 micro‐pillar arrays. The 3D R‐GO sensor is highly responsive to low concentration of ammonia (NH3) and nitrogen dioxide (NO2) diluted in dry air at room temperature. Compared to the two‐dimensional planar R‐GO sensor structure, as the result of the increase in sensing area and interaction cross‐section of R‐GO on the same device area, the 3D R‐GO gas sensors show improved sensing performance with faster response (about 2%/s exposure), higher sensitivity, and even a possibly lower limit of detection towards NH3 at room temperature.

Flexible Transparent Reduced Graphene Oxide Sensor Coupled with Organic Dye Molecules for Rapid Dual‐Mode Ammonia Gas Detection

“…By using the method described in our previous work, [14] the sensitivity (i.e., the slope in the ΔR/R vs gas concentration) was determined to be 0.031% ± 0.005% ppm −1 for NH 3 gas in dry air. To understand the response behavior of the BPB/R-GO sensing materials toward NH 3 gas, measurements of the transfer characteristics of the gated BPB/R-GO sensor (for a schematic of the gated sensor see Figure S2a of the Supporting Information) were also performed.…”

“…Additionally, our data from R-GO and BPB/R-GO devices indicate that both the device design and the selected sensing materials can significantly impact the device performance, as reported in our previous work. [14] To study the workability of our flexible chemiresistor under strain, cyclic bending tests (50 cycles at each strain) were performed in an ambient environment (as shown in Figure S3a of the Supporting Information) to observe the relationship between device resistance change and strain by using the method described in our previous work. [42] The device resistance increased with increasing bending radius (i.e., strain).…”

“…[12,13] Therefore, in addition to device miniaturization methods to reduce power consumption, developing better sensing materials to enhance the sensing performance is also necessary for wearable electronics. [13,14] Currently, the materials selected to construct superior chemical sensing devices are low-dimensional nanoscale materials; this preference is mainly due to the special surface properties of these materials. [15][16][17][18] Among the variety of existing nanomaterials, reduced graphene oxide (R-GO), which possesses many of the properties necessary for high performance chemical sensors (e.g., a large surface-to-volume ratio, good conductivity, flexibility, low-temperature workability, easily tunable chemical properties, etc.…”

MoS2 graphene fiber based gas sensing devices

“…A C C E P T E D ACCEPTED MANUSCRIPT 2 As a typical graphene-liked 2D layered n-type semiconductor, MoS 2 is composed of three atom layers (S-Mo-S) and stacked through van der Waals force (vdW). What is more, when the numbers of MoS 2 layers is reduced, the indirect band gap becomes direct and wide high luminescence efficiency [14,15] .…”

“…Nanomaterials have attracted much attention in gas sensing devices owing to their improvement in surface-to-volume ratio characteristics [1][2][3] . In particular, graphene-based gas sensors have recently attracted intensive attention, mainly due to the atomically thin-layered 2D structure and excellent electrical properties of graphene sheets [4][5][6][7] .…”