Nowadays, the Internet of Things (IOT), electronics, and neural interfaces are becoming an integral part of our life. These technologies place unprecedentedly high demands on materials in terms of their mechanical and electrical properties. There are several strategies for forming conductive layers in such composites, e.g., volume blending to achieve a percolation threshold, inkjet printing, lithography, and laser processing. The latter is a low-cost, environmentally friendly, scalable way to produce composites. In our work, we synthesized AgNW and characterized them using Ultraviolet-visible spectroscopy (UV-vis), Transmission electron microscopy (TEM), and Selective area electron diffraction (SAED). We found that our AgNW absorbed in the UV-vis range of 345 to 410 nm. This is due to the plasmon resonance phenomenon of AgNW. Then, we applied the dispersion of AgNW on the surface of the polymer substrate, dried them and we got the films of AgNW.. We irradiated these films with a 432 nm laser. As a result of the treatment, we observed two processes. The first one was the sintering and partial melting of nanowires under the influence of laser radiation, as a consequence of which, the sheet resistance dropped more than twice. The second was the melting of the polymer at the interface and the subsequent integration of AgNW into the substrate. This allowed us to improve the adhesion from 0–1 B to 5 B, and to obtain a composite capable of bending, with radius of 0.5 mm. We also evaluated the shielding efficiency of the obtained composites. The shielding efficiency for 500–600 nm thick porous film samples were 40 dB, and for 3.1–4.1 µm porous films the shielding efficiency was about 85–90 dB in a frequency range of 0.01–40 GHz. The data obtained by us are the basis for producing flexible electronic components based on AgNW/PET composite for various applications using laser processing methods.
1 January 2020 in Progress In Electromagnetics Research Letters
We propose a new method to match diplexer channels with a common port in which a Π-shaped strip conductor is used as a matching circuit. The applicability of the method is illustrated by simulating and fabricating a microstrip diplexer for GPS/GLONASS applications. The central frequencies of the channels are 1.234 GHz and 1.597 GHz, and their fractional bandwidths are 6.8% and 7.3%, respectively; minimum insertion losses are 1.05 dB and 1.08 dB. The main advantage of the diplexer is its compact size: 16.8 mm × 9.0 mm × 6.4 mm in housing. Using 1D models and a quasi-TEM approach, the frequency-dependent coupling coefficients between the matching circuit and input resonators of the channels are calculated, and the influence of the matching circuit's geometrical parameters on its coupling with diplexer channels is studied.
Transparent conductive electrodes that combine flexibility with effective electromagnetic interference (EMI) shielding are important for next-gen flexible electronics and 5G/6G communication devices. Achieving high optical transparency, low sheet resistance, and broadband shielding performance remains a sophisticated task. This work demonstrates a solution: the synthesis and comprehensive characterization of flexible In2O3/Ag/In2O3 (IAI) structures on polyethylene terephthalate substrates. The optimized structure with a 13.2 ± 1.1 nm silver interlayer achieves an incredible combination of properties: high optical transmittance (82.59% at 500 nm), low sheet resistance (6.4 ± 0.8 Ω/sq), and insignificant optical haze (1.04%). Broadband EMI shielding measurements from 10 MHz to 1 THz reveal a uniform shielding effectiveness of 25–30 dB across band from radiowave to terahertz. The IAI structures also show outstanding mechanical resilience, maintaining their electrical and shielding performance under repeated bending. This unique set of attributes positions IAI thin films as a prospective material for transparent EMI shielding in advanced telecommunications and flexible optoelectronics.
1 March 2018 in Journal of Siberian Federal University. Mathematics & Physics
Сибирский федеральный университет (СФУ) входит в топ-15 вузов России. Ведущие научные школы Красноярска. Лучший в России кампус. Мировые индустриальные партнёры
1 January 2019 in Progress In Electromagnetics Research M
For the first time, an environmentally friendly waste-free closed cycle for the formation of EMI shielding materials that are promising for 5G communications is considered. Based on the proposed closed technological cycle, two types of EMI shielding materials have been obtained; both materials have significant prospects for signal shielding in all ranges that are allocated in different countries for 5G communication. The first type of materials are transparent conductive meshes with a transparency of more than 80% and with a shielding efficiency of more than 40 dB in the S and L bands and about 30 dB in the K and Ka bands. The study of signal reflection characteristics in the S, L, C, K and Ka bands showed the promise of using these materials as transparent 5G signal reflectors. The reflection coefficient in all considered ranges is above 90% (-0.5 dB). The second type of shielding material are continuous silver micro caps films characterized by a shielding efficiency of 90.1 dB at a thickness of 6.2±1.2 µm. We have also shown that silver micro caps can separate into silver flakes and ribbons when sonicated. These materials can also be used to produce EMI shielding coatings and composites. A detailed analysis of the shielding properties showed that each type of materials obtained in a closed technological cycle is comparable with the best literature results and significantly wins in terms of cost.