Graphene has been intensively studied due to its outstanding electrical and thermal properties. Recently, it was found that the heat generation by Joule heating of graphene is limited by the conductivity of graphene. Here we suggest an alternative method to generate heat on a large-area graphene film more efficiently by utilizing the unique electromagnetic (EM) wave absorption property of graphene. The EM wave induces an oscillating magnetic moment generated by the orbital motion of moving electrons, which efficiently absorbs the EM energy and dissipate it as a thermal energy. In this case, the mobility of electron is more important than the conductivity, because the EMinduced diamagnetic moment is directly proportional to the speed of electron in an orbital motion. To control the charge carrier mobility of graphene we functionalized substrates with self-assembled monolayers (SAM). As the result, we find that the graphene showing the Dirac voltage close to zero can be more efficiently heated by EM waves. In addition, the temperature gradient also depends on the number of graphene. We expect that the efficient and fast heating of graphene films by EM waves can be utilized for smart heating windows and defogging windshields.

The decolorization of paintings, photographs, and artworks is a common phenomenon related to the oxidative degradation of color dyes reacting with oxygen or water molecules, which also causes a critical problem in organic light-emitting diodes (OLEDs). It is expected that the gas-impermeable property of graphene and h-BN can be utilized to protect the color dyes from degradation. However, the transfer method has been limited to a polymer with high glass transition temperature (T g) or a glass substrate due to hot or wet transfer conditions. Here, we report the dry transfer coating of the graphene barrier films on flexible substrates at room temperature using a roll-to-roll process to prevent the bleaching of color dyes, which can be widely used to protect various colorization and light-emitting materials for sustainable printing and display technologies in the future.

Purpose The purpose of this paper is to evaluate the effects of intermittent and continuous heating protocols using graphene-heated clothing and identify more effective body region for heating in a cold environment. Design/methodology/approach Eight males participated in five experimental conditions at an air temperature of 0.6°C with 40 percent relative humidity: no heating, continuous heating the chest, continuous heating the back, intermittent heating the chest, and intermittent heating the back. Findings The results showed that the electric power consumption of the intermittent heating protocol (2.49 W) was conserved by 71 percent compared to the continuous protocol (8.58 W). Rectal temperature, cardiovascular and respiratory responses showed no significant differences among the four heating conditions, while heating the back showed more beneficial effects on skin temperatures than heating the chest. Originality/value First of all, this study was the first report to evaluate cold protective clothing with graphene heaters. Second, the authors provided effective intermittent heating protocols in terms of reducing power consumption, which was able to be evaluated with the characteristics of fast-responsive graphene heaters. Third, an intermittent heating protocol on the back was recommended to keep a balance between saving electric power and minimizing thermal discomfort in cold environments.