Ultrahigh Temperature Graphene Molecular Heater

Abstract

for metal films, [10] which are the basic building blocks of traditional heaters, after reducing the thickness strongly inhibits the realization of molecular heaters. Therefore, it is of great importance to find a satisfactory molecular building block with thicknesses controlled at the atomic level and unique electrical properties to achieve the construction of molecular heater.Graphene, which can be considered as a polycyclic aromatic hydrocarbon molecule with strictly atomic thickness, has been known as an excellent conductor of both heat and electricity. [11] Regarding that the electrothermal conversion of the heater is driven by the collision of charged particles in the electric field, also known as Joule heating, the heat performance is determined by the current flow and the intrinsic resistance of it. The extremely high current density [12] (≈2 × 10 9 A cm −2 ) and thermal conductivity [13] (≈5300 W m −1 K −1 ), as well as relatively low thermal loss, [14] where the convective heat-transfer coefficient is 12.4 W cm −2 °C −1 , of graphene could provide an anticipated heating performance, thus making the graphene molecule a promising building block of the molecular heater. However, the catalytic-growth characteristic of graphene makes it hard for direct growth on insulated substrate, thus the as-fabricated films suffer from the significant drawback of low crystallinity and nonuniformity. [15][16][17] Meanwhile, the transferred graphene is also criticized because of its cracks and residues, which leads to decayed electrical and thermal properties. Therefore, the heat temperature was limited to ≈200 °C in previous graphene-based heaters. [18] Here, graphene molecules with thicknesses controlled at the atomic level were directly grown on ceramic substrates, where the achievement of high-quality and uniform distribution characteristics had been demonstrated successfully. Graphene molecular heater (GMH), which exhibited extremely high heating temperature up to ≈400 °C only at a very low input voltage of 4.3 V, based on 1-nm-thick graphene molecule was first achieved and its heating characteristics were systematically explored, including the Joule heating efficiency, temperature distribution, and heating rate, where all the heating performances exhibit promising characteristics. What's more, the heating temperature of the GMH could be further improved to 600 °C, which was far beyond the oxidation temperature of graphene molecule in the atmosphere, after being encapsulated by hexagon boron nitride (h-BN) molecule. Thus, we believe the as-constructed GMH could further enrich the Although a number of molecular devices have been fabricated successfully, molecular heater still keeps blank. It is of great importance to find a satisfactory molecular building block with thicknesses controlled at the atomic level and outstanding electrical properties to achieve the construction of molecular heater. Graphene, a polycyclic aromatic hydrocarbon molecule with strictly atomic thickness, is known as a superior heat and electricit...

Multi‐Level Electro‐Thermal Switching of Optical Phase‐Change Materials Using Graphene

“…To minimize the contact resistance between electrodes and graphene, a 1D edge coupling approach [ 86 ] or patterning the electrodes [ 87 ] could reduce the total voltage required to dissipate P Am on the heater. Morever, to avoid the current saturation and reach high temperatures, multi‐layer graphene could be used, [ 88 ] and hexagonal boron nitride encapsulated graphene devices can be used as they sustain high lattice temperature up to ≈1600 K. [ 66 ] Finally, to reduce the sheet resistance and also avoid the current saturation, a gate terminal could be added to control the charge doping of graphene. [ 60 ]…”

Tunable absorber embedded with GST mediums and trilayer graphene strip microheaters

“…Investigators have reported various techniques to exploit graphene as the microheater for GST mediums [40][41][42][43] . In this stream, Rios et al 37 demonstrated the optoelectronic framework incorporating undoped monolayer graphene heater to perform reversible and controllable switching between four different levels of crystallinity for a large area of GST medium.…”

“…41 discusses the techniques to enhance the Joule performance of graphene heater, and reports on decreasing the sheet resistance and minimizing the contact resistance between graphene layer and electrodes. Within the context, the sheet resistance of graphene is inversely related to its bidimensional conductivity-the factor that can be defined by the electron relaxation time and the numbers of layers 33,42 . Hung et al 42 showed that increasing the number of graphene layers up to 4, thereby contributing to nearly 1 nm total thickness, would increase the Joule performance; a high temperature up to 600 °C can be achieved at a low voltage of 4.3 V. However, they showed that the use of graphene layer thickness > 1 nm slightly increases the sheet resistance (of heater) since the increased edge structure would reduce the heating efficiency.…”

A Nanofibrillated Cellulose-Based Electrothermal Aerogel Constructed with Carbon Nanotubes and Graphene

“…Due to their excellent electrical conductivity and thermal conductivity [ 5 , 6 , 7 , 8 ], they were involved in many researches on functional materials. Of which, electrothermal functional composite can convert electrical energy into thermal energy on the basis of Joule heating principle principally due to the inelastic collision of charged particles under the electric field [ 9 ]. Recently, related studies reported various electrothermal composites made of CNTs or GP, which can be used for medical infusion apparatus [ 10 ], deicing [ 11 , 12 ], defrosting and defogging [ 13 , 14 , 15 ], repairing and self-curing resin [ 16 ], and other fields [ 17 , 18 , 19 , 20 ].…”