Yazar "Lee, Seungjun" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Cold spray-based rapid and scalable production of printed flexible electronics
    (Elsevier, 2022) Akin, Semih; Lee, Seungjun; Jo, Seunghwan; Ruzgar, Duygu Gazioglu; Subramaniam, Karthick; Tsai, Jung -Ting; Jun, Martin Byung-Guk
    Flexible electronics (FE) is attracting great attention from both scientific and industrial communities, and plays a crucial role in smart device applications. Despite great promise, traditional printing approaches (e.g., screen printing, ink-jet printing, etc.) often need a high-temperature post-sintering process to produce FE with desired electrical conductivity and adhesion strength. The post-sintering processes, however, often lead to fast oxidation of the functional coating while limiting the use of low-thermal budget substrates. Exponential advance of FE in a large-scale and energy-efficient manner relies on rationally eliminating the post-sintering processes. To this end, with the aim of uncovering process-structure-properties relationships, we employ the emerging cold spray (CS) technique for rapid and scalable production of FE without a need for high-temperature post-sintering. In this regard, micron-scale Tin (Sn) particles are directly written on a flexible polymer substrate (PET) by cold spraying under ambient conditions. The effect of CS process parameters on the resultant coatings is comprehensively characterized in terms of microstructure, film thickness, electrical conductivity, linewidth, and adhesion strength. The resulting electrodes show excellent electrical conductivity (6.98 x 105 S m-1), adhesion strength, long-term stability, and flexibility without significant conductivity loss after 1000 bending cycles. By leveraging the CS operational settings, a resistive macro-heater (12 x 15 cm2) and an LED circuit (2.5 cm x 18 cm) are fabricated to demonstrate the applicability of the CS in printed FE. Moreover, to address the low-spatial reso-lution of CS writing, a case study on sequential CS and femtosecond laser machining is performed, which further led to ultra-high resolution (i.e., 30 mu m linewidth) custom-designed flexible electrodes. Thus, the present study reveals the immense potential of the CS technique for rapid and scalable production of FE without the need for post-sintering.
  • Küçük Resim Yok
    Öğe
    Highly Flexible, Conductive, and Antibacterial Surfaces Toward Multifunctional Flexible Electronics
    (Korean Soc Precision Eng, 2024) Ruzgar, Duygu Gazioglu; Akin, Semih; Lee, Seungjun; Walsh, Julia; Lee, Hyowon Hugh; Jeong, Young Hun; Jun, Martin Byung-Guk
    Conductive metallization of polymer surfaces, owing to the integration of unique features of dissimilar materials (i.e., polymer + metal), is becoming the central focus in flexible polymer electronics. However, fabrication of multifunctional surfaces on polymers in a high-throughput and robust manner at ambient conditions remains challenging. In this study, we employ the cold spray (CS) particle deposition technique to produce multifunctional hybrid surfaces on a flexible polymeric substrate (PET) toward flexible electronics. In this regard, soft metal particles (Sn), are deposited on the polymer surface as an interlayer followed by the over-coating of hard metal (Cu) film to create hybrid (Sn + Cu) surfaces. Studies on microstructure, adhesion strength, and water contact angle are conducted to characterize the resulting surface structure. By leveraging the optimum CS settings, multifunctional surfaces with promising electrical conductivity (5.96 x 10(5) S.m(-1)), flexibility, adhesive strength, and hydrophobicity (contact angle approximate to 122 degrees) were achieved. Moreover, the antibacterial performance of the surface is confirmed by the in vitro antibacterial tests in a manner that > 99% of the bacteria were inhibited. This work provides a promising strategy for high-throughput manufacturing of multifunctional surfaces (flexible + conductive + antibacterial surfaces) toward multifunctional flexible electronics.