Flexible Fabrication of Flexible Electronics: A General Laser Ablation Strategy for Robust Large‐Area Copper‐Based Electronics

Abstract

toward flexibility, intelligence, and high integration, and the materials with good photoelectric performance, excellent processibility, low cost, good reliability, and chemical stability are highly desirable.Compared with traditional rigid devices, flexible electronics can adapt to different working environments and meet the requirements of various deformations while maintaining the normal functions of electronic devices. In flexible photoelectric devices, the flexible transparent conducting electrodes (FTCEs) are an indispensable part, and currently the most widely used FTCE is indium tin oxide (ITO)-coated transparent plastic film. However, ITO coated film has the following shortcomings: high cost of indium, large material waste in the production process, the requirement of expensive highvacuum equipment, and the most important one-intrinsic brittleness of ITO, which is incompatible with the future lowcost wearable flexible electronic devices. [13] In order to develop inexpensive and reliable alternatives of ITO, many novel materials and fabrication methods have been put forward. Metal nanowires (NWs) are considered to be the most promising alternatives of ITO for fabricating high-performance FTCEs. [13] Recently, silver nanowires mesh structures have been widely employed as conductive layer on flexible transparent substrate, and superior light transmission and conductivity have been obtained. More importantly the performance degradation of Attributed to high power density and controllable digital program operation, lasers are a powerful tool in the preparation, prototype fabrication, and post-processing of materials. In this paper, a general laser ablation strategy that can be conducted under ambient, room-temperature, and mask-free conditions is employed for the rapid fabrication of robust large-area copperbased flexible electronics. Micrometer-scale thick copper layer cladded on flexible polymer substrate can be removed efficiently in one laser scanning pass based on laser-induced heat evaporation effect. Metal grids with a width less than 10 microns and a thickness close to 2 microns can be produced in a reliable manner. As proof-of-concept demonstrations, flexible transparent conducting electrodes and a variety of flexible circuit boards (FCBs) with different precisions and dimensions are fabricated by this approach in a digitally controlled mode and their photoelectric properties under normal and deformation states are investigated. The results indicate that the method is robust and asprepared flexible electrodes and circuits are reliable and endurable, indicative of the potential of this method in scalable fabrication of sub-millimeter flexible electronics through a straightforward and flexible fashion.

A new strategy for the fabrication of a flexible and highly sensitive capacitive pressure sensor

“…The structure of the traditional capacitive sensor is different from ours, with the top layer being PET single-sided adhesive tape as the packaging layer, the middle layer being an MXene/PVP filter paper membrane as the sensitive layer and the bottom layer being a copper interdigital electrode on a flat polyethyleneterephthalate (PET) substrate as the output signal layer. The PET-Cu interdigital electrode layer was prepared by the previously reported laser ablation process 32 . Figure S1 (Supplementary Information) shows a photograph of the PET-Cu interdigital electrode prepared by the laser ablation strategy.…”

“…Fabrication of a flexible electrode circuit board by the laser ablation strategy can be found in previous reports 32 . The PET-Cu interdigital electrode and sensor array electrode were fabricated by laser irradiation of the copper-clad PET film with a 3 W diode-pumped Nd: YAG laser.…”

Laser‐Induced Graphene on Paper toward Efficient Fabrication of Flexible, Planar Electrodes for Electrochemical Sensing

“…Moreover, the applicability that has been proven in laser-enabled techniques for LIG production in flexible substrates such as PI and paper, has given the possibility to apply these approaches in flexible electronics. Besides the direct synthesis of materials in which LIG is included, other laser-based approaches for substrate microprocessing [29] and surface treatment are achievable, in an abundant list of materials, including polymers, [30] graphene [31] or metallic surfaces and nanoparticles, [32] for patterning and fabrication of active electronic elements and to potentiate the electric and conductive properties of many materials. Powered by these laser processing techniques, LIG has shown promising properties to complement such approaches, as well as conventional printing techniques, including screenprinting [33] and inkjet printing, [34] to develop active elements in flexible electronics for application in bioelectronic systems, such as conductive films, [35] supercapacitors [36] and biofuel cells [37] that can be integrated with biosensors for comprehensive, multifunctional, self-sustainable applications.…”

Optically Transparent and Highly Conductive Electrodes for Acousto-Optical Devices

“…Based on the literature data [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 ], Figure 2 plots of the technological limitations of various approaches to forming grooves in transparent materials or directly forming conductors on the substrate surface. The markers show the values of the width and depth of the groove’s or line’s height, obtained from the literature sources, and the lines show the t...…”