# Laser-Induced Graphene Film and Its Applications in Flexible Electronics
## 2 Applications of Laser-Induced Graphene in Flexible Electronics  
This Special Issue includes relevant works about the advanced manufacturing of LIG films and their applications in flexible electronics. As one of the most important components in the Internet of Things era, flexible wearable sensors are greatly needed in the near future. Based on its excellent physical and chemical properties, LIG film has been widely used in quite a variety of flexible sensors, such as sound sensors [5, 6], gas sensors [7, 8], humidity sensors [9], biosensors [10, 11], electrochemical sensors [12], strain sensors [13], and pressure sensors [14, 15]. For example, [PERSON] et al. [5] developed an intelligent LIG artificial throat that can generate and detect sounds in a single device. Due to the porous structure, high thermal conductivity and low heat capacity of LIG films, the artificial throat has a completely different working mechanism compared with the conventional acoustic transducers. An intelligent artificial throat can detect simple throat vibrations and convert them into controllable sounds, thus showing great potential to assist people with disabilities affecting their speech. [PERSON] et al. [8] fabricated LIG gas sensor arrays that can be incorporated on a variety of surfaces to detect a broad range of gases. The gas sensors exhibit fast response times owing to the large surface area (\(\sim\)350 m\({}^{2}\) g\({}^{-1}\)) and good thermal conductivity of LIG, wherein its thermal conductivity is similar to thermal conductivity detectors or katharometers. [PERSON] et al. [9] employed porous LIG and graphene oxide as humidity-sensing materials and prepared a flexible capacitive-type interdigital humidity sensor with low hysteresis, high sensitivity, and long-term stability. In addition, LIG was also used in wearable biosensors with high accuracy and low detectable concentrations. However, the long-term chemical and electrochemical stability of LIG does not satisfy practical applications. In view of this, [PERSON] et al. [10] reported a strategy to engineer an LIG surface with Au clusters and chitosan to form C\(-\)Au\(-\)LIG electrodes with superhydrophilic and conductive 3D graphene surfaces, which show good performance and negligible attenuation in long-term storage and utility. Similarly, [PERSON] et al. [12] built a laser-enabled flexible LIG electrochemical sensing system on a finger to electrochemically identify chloramphenicol, denbuterol and ractopamine in meat in situ and in a fast and real-time manner. In the aspect of strain and pressure sensors, LIG films also exhibit some unique advantages due to their good electrical conductivity. [PERSON] et al. [15] developed a flexible high-resolution (8 dpi) triboelectric sensor array based on patterned high-quality LIG electrode (7 \(\Omega\) sq\({}^{-1}\)) for self-powered, real-time tactile sensing. The sensor platform shows outstanding durability and synchronicity, enabling real-time visualization of multipoint touch, sliding, and tracking motion trajectory without power consumption. Based on the triboelectric sensor platform, a smart wirelessly controlled human-machine interaction system was also constructed to wirelessly control personal electronics. In addition to flexible sensors, many of the publications collected in this Special Issue focus specifically on micro-supercapacitors and actuators. In terms of micro-supercapacitors, [PERSON] et al. [1] first reported the processing technique of LIG films and their unique applications in flexible micro-supercapacitors. Due to their high surface area and high electrical conductivity (<15 \(\Omega\) sq\({}^{-1}\)), LIG films are very suitable for energy storage, especially for in-plane micro-supercapacitors [2]. The LIG-based micro- supercapacitors deliver an areal capacitance of >4 mF cm\({}^{-2}\) and a power density of 9 mW cm\({}^{-2}\).