Flexible and Transparent Gas Molecule Sensor Integrated with Sensing and Heating Graphene Layers

Abstract

Graphene leading to high surface-to-volume ratio and outstanding conductivity is applied for gas molecule sensing with fully utilizing its unique transparent and flexible functionalities which cannot be expected from solid-state gas sensors. In order to attain a fast response and rapid recovering time, the flexible sensors also require integrated flexible and transparent heaters. Here, large-scale flexible and transparent gas molecule sensor devices, integrated with a graphene sensing channel and a graphene transparent heater for fast recovering operation, are demonstrated. This combined all-graphene device structure enables an overall device optical transmittance that exceeds 90% and reliable sensing performance with a bending strain of less than 1.4%. In particular, it is possible to classify the fast (≈14 s) and slow (≈95 s) response due to sp(2) -carbon bonding and disorders on graphene and the self-integrated graphene heater leads to the rapid recovery (≈11 s) of a 2 cm × 2 cm sized sensor with reproducible sensing cycles, including full recovery steps without significant signal degradation under exposure to NO2 gas.

Transparent and Flexible Cellulose Nanocrystal/Reduced Graphene Oxide Film for Proximity Sensing

“…The durability, consistency, refl ection by ambient light, etc. were also checked to explore the full potential of these touch-screen sensors [ 28,29 ] and the developed CNC/GO overrules the large, power-consuming, costly, and visible IR proximity detectors used nowadays. The current proximity sensor leaps ahead of the currently used capacitive proximity sensors with their limited sensing distance and provides users with a direct, quick, and easy way to interact based on electromechanical principles.…”

Human‐Like Sensing and Reflexes of Graphene‐Based Films

“…Furthermore, heating was also an effective method to recover sufficiently. By integrating with graphene sensor and graphene heater ( Figure 13 ), the faster recovering of the graphene sensor has been proved (Figure 13e) 107. And attributing to the flexibility of graphene, the sensitivity of the sensor was secured with ΔR/R 0 of 12% for 1 ppm NO 2 when applied bending strain of 1.4% (Figure 13f).…”

“…Similar as the binding between odor and olfaction receptor neuron ( Figure 11 ),105 gas molecules would adsorb on the graphene sheets and induce conductance changes of graphene, which can be detected by measuring the changes of the electrical signal of graphene. Here, there are three modes of the interaction between gas molecules with graphene: a) influencing the conductance of graphene by redistributing electrons, such as H 2 O;106 b) contributing electrons or holes to graphene to change its electron concentration, such as NO 2 ;107 c) forming covalent bonds 108. Because of the adsorption of water molecules in air, the graphene often exhibits p‐type.…”

Observation of convection phenomenon by high-performance transparent heater based on Pt-decorated Ni micromesh

“…The development of transparent and flexible heaters with high performances is necessary for fabricating high-quality transparent flexible sensors for gases and particulate matters (PM). 1,2 In general, the heaters in such sensors are the main technical factors for enhancing the selectivity, sensitivity, and response and recovery speeds of the sensors, or the adsorption and desorption the target materials (gas or PM). 1,2,[16][17][18][19] In this study, a high-performance transparent heater based on Pt-decorated Ni micromesh was fabricated by a combination of transfer printing process and Pt sputtering.…”

“…1,2 In general, the heaters in such sensors are the main technical factors for enhancing the selectivity, sensitivity, and response and recovery speeds of the sensors, or the adsorption and desorption the target materials (gas or PM). 1,2,[16][17][18][19] In this study, a high-performance transparent heater based on Pt-decorated Ni micromesh was fabricated by a combination of transfer printing process and Pt sputtering. 11,20 The resulting Ni micromesh-based heater with Pt decoration exhibited excellent mechanical durability, such as adhesion to substrates and flexibility, and heat-generating performance.…”