With the extensive industrial growth driven by the Fourth Industrial Revolution and the excessive use of fossil fuels, greenhouse gas emissions have accelerated global warming. Energy harvesting technologies have garnered significant attention as a potential solution to this issue. Among them, triboelectric nanogenerators (TENGs) have emerged as promising candidates for energy collection and conversion. However, TENGs typically face limitations in providing an efficient energy supply due to their high output voltage and low output current. To overcome these challenges, numerous studies have explored various methods to enhance the output performance by increasing the surface area of the triboelectric materials. Herein, we report a high-output TENG fabricated through a simple scratch process. By utilizing sandpaper, typically used for abrasion or polishing, the surface roughness of the triboelectric material PFA was increased through surface scratching. The surface-engineered TENG, prepared through this simple and rapid process, demonstrated enhanced output characteristics with a voltage of 276 V and a current of 72 μA, showing a 21% increase in voltage and a 41% increase in current compared to the non-engineered counterpart, providing sufficient energy to power an LED. These results indicate that the scratch-based surface modification process using sandpaper offers an effective solution for improving triboelectric output performance, establishing TENGs as a key contributor to sustainable energy supply.

Next-generation display technologies, including rollable and foldable displays, are advancing rapidly, enabling innovative and versatile form factors. Flexible displays predominantly utilize materials such as Polyimide (PI), Colorless Polyimide (CPI), and Thermoplastic PolyUrethane (TPU) due to their exceptional flexibility and durability. However, a significant challenge lies in the lack of standardized criteria for evaluating the durability of these flexible substrates. In this study, the durability of these materials under rolling conditions was investigated. This study establishes a standardized methodology for evaluating flexible materials used in rollable displays. Experiments were performed on PI, including rolling and scratch tests with varying indenter sizes. Friction data from the scratch tests, combined with cross-sectional analyses, were examined using optical microscopy and Scanning Electron Microscopy (SEM). The scratch test results revealed that PI films with lower elastic recovery exhibited distinct damage patterns during rolling cycles, especially when smaller indenter radius were used. As the number of rolling cycles increased, the critical force decreased rapidly. This behavior was attributed to the weakening or breaking of atomic bonds within the film. This was further confirmed by SEM images, which revealed delamination of the film from the surface after rolling.