## 3 Thin-Film Materials and Their Applications
### Organic Thin-Films
#### 3.2.2 Inorganic-Organic Hybrid Thin-Films  
Inorganic-organic composite systems are another significant research filed of the microelectronics. Such as nanostructure materials (e.g., metal and/or oxide nanoparticles) embedded in organic thin-films, perovskite thin-films with organic functional groups (e.g., CH\({}_{3}\)CH\({}_{3}\)BrI\({}_{3}\)), and so on. In the industry, nanostructured thin films are manufactured in various ways. Solution-processed [174; 183], green electrospinning technique [184], embedded with nanoparticles, shaped with nanostructuring techniques, or hybridized with other systems or functionalized with bio nanotechnological methods are used. Different ways can result in different properties [178]. These properties include photocatalytic, antibacterial, antifouling, and abrasion-resistant. With the development of nanotechnology, the production of various forms of nanostructured materials is added to organic materials, such as nano-layers, nanoparticles, and nanowires. It is reported that the environmental-friendly N-doped TiO\({}_{2}\) (N-TiO\({}_{2}\)) nanorods in regenerated cellulose composite thin films were designed as a green portable photocatalyst by utilizing recycled newspaper as a sustainable cellulose resource [185]. The fabrication process is environmental-friendly and shows great potential in the field of water and wastewater treatment applications. Catalytic thin-films offer great potential for green technology applications in order to save energy, combat pollution, and reduce global warming [185; 186]. In 2016, an article reported a biodegradable triboelectric nanogenerator (BD-TENG) capable of using in vivo biomechanical energy harvesting [187]. This BD-TENG is posed of the biodegradable polymer as the frictional layer and resorbable metals (Mg film) as the electrode layers, which can be degraded and resorbed in an animal body. The output performance in vivo, biocompatibility, and tunable degradation property of the BD-TENG were systematically analyzed. Excellent experimental results demonstrate the potential as a power for transient medical devices, which can be used to supply in the field of biomedical science, especially in vivo sensors and therapeutic devices. Biomedical science has developed rapidly and achieved great results in recent years. The prepared nanofiber films, owing to the green electrospinning technique and the appropriate content, get higher points in the biocompatibility and biodegradation test [184]. In addition, the results of the cytotoxicity reveal the possibility of coexistence with human dermal fibroblast cells. In conclusion, the nanofiber films show the potential to be applied in skin tissue engineering scaffold applications. Such degradable, resorbable and/or compatible hybrid inorganic-organic thin films are able to implement transient electronic devices. In 2017, [PERSON] et al. fabricated the dissolvable and recyclable random laser (DRRL) based on the mixture of semiconductor NPs with a water-soluble polymer [188]. ZnO NPs (gain media) and TiO\({}_{2}\) NPs (scattering media) are embedded into PVA. The dissolvable behaviors of the DRRL were studied in water, and the recycling capability was also demonstrated. The NPs-embedded in polymer-based lasers can be dissolved completely in DI water and can be reused for several times. [PERSON] et al. proposed a degradable poly (vinyl alcohol)-based (PVA-based) composite thin-films doped with TiO\({}_{2}\) NPs (PVA/TiO\({}_{2}\)) [189]. Through controlling the TiO\({}_{2}\) nanoparticle addition, the dielectric properties and dissolution rate of the composite film can be tuned. The PVA/TiO\({}_{2}\) water-solubility composite was also used to further design and fabricate patch antennas, which could be physically degraded in pure water. In 2019, foldable and biodegradable energy-storage devices based on copy papers were developed by [PERSON] et al. [190].