Functional Metallic Microcomponents via Liquid-Phase Multiphoton Direct Laser Writing: A Review

We present an overview of functional metallic microstructures fabricated via direct laser writing out of the liquid phase. Metallic microstructures often are key components in diverse applications such as, e.g., microelectromechanical systems (MEMS). Since the metallic component’s functionality mostly depends on other components, a technology that enables on-chip fabrication of these metal structures is highly desirable. Direct laser writing via multiphoton absorption is such a fabrication method. In the past, it has mostly been used to fabricate multidimensional polymeric structures. However, during the last few years different groups have put effort into the development of novel photosensitive materials that enable fabrication of metallic—especially gold and silver—microstructures. The results of these efforts are summarized in this review and show that direct laser fabrication of metallic microstructures has reached the level of applicability.

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On-chip replication of high-sag micro-optical components fabricated by direct laser writing

10.1117/12.591719 ◽

2005 ◽

Cited By ~ 1

Author(s):

Daniel Asselin ◽

Patrice Topart ◽

Lieyi Sheng ◽

Felix Cayer ◽

Sebastien Leclair ◽

...

Keyword(s):

Direct Laser Writing ◽

Laser Writing ◽

Optical Components ◽

Direct Laser ◽

On Chip

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Direct laser writing of liquid crystal elastomers oriented by a horizontal electric field

Open Research Europe ◽

10.12688/openreseurope.14135.2 ◽

2021 ◽

Vol 1 ◽

pp. 129

Author(s):

Marco Carlotti ◽

Omar Tricinci ◽

Frank den Hoed ◽

Stefano Palagi ◽

Virgilio Mattoli

Keyword(s):

Liquid Crystal ◽

Electric Field ◽

Microelectromechanical Systems ◽

Functional Materials ◽

Direct Laser Writing ◽

Static Electric Field ◽

Laser Writing ◽

Printing Process ◽

Direct Laser ◽

Liquid Crystal Elastomers

Background: The ability to fabricate components capable of performing actuation in a reliable and controlled manner is one of the main research topics in the field of microelectromechanical systems (MEMS). However, the development of these technologies can be limited in many cases by 2D lithographic techniques employed in the fabrication process. Direct Laser Writing (DLW), a 3D microprinting technique based on two-photon polymerization, can offer novel solutions to prepare, both rapidly and reliably, 3D nano- and microstructures of arbitrary complexity. In addition, the use of functional materials in the printing process can result in the fabrication of smart and responsive devices. Methods: In this study, we present a novel methodology for the printing of 3D actuating microelements comprising Liquid Crystal Elastomers (LCEs) obtained by DLW. The alignment of the mesogens was performed using a static electric field (1.7 V/µm) generated by indium-tin oxide (ITO) electrodes patterned directly on the printing substrates. Results: When exposed to a temperature higher than 50°C, the printed microstructures actuated rapidly and reversibly of about 8% in the direction perpendicular to the director. Conclusions: A novel methodology was developed that allows the printing of directional actuators comprising LCEs via DLW. To impart the necessary alignment of the mesogens, a static electric field was applied before the printing process by making use of flat ITO electrodes present on the printing substrates. The resulting microelements showed a reversible change in shape when heated higher than 50 °C.

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Lotus-on-chip: computer-aided design and 3D direct laser writing of bioinspired surfaces for controlling the wettability of materials and devices

Bioinspiration & Biomimetics ◽

10.1088/1748-3190/aa82e0 ◽

2017 ◽

Vol 12 (6) ◽

pp. 066004 ◽

Cited By ~ 12

Author(s):

Andrés Díaz Lantada ◽

Stefan Hengsbach ◽

Klaus Bade

Keyword(s):

Computer Aided Design ◽

Direct Laser Writing ◽

Laser Writing ◽

Direct Laser ◽

Computer Aided ◽

On Chip ◽

Aided Design

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Hierarchically Porous, Laser-Pyrolyzed Carbon Electrode from Black Photoresist for On-Chip Microsupercapacitors

Nanomaterials ◽

10.3390/nano11112828 ◽

2021 ◽

Vol 11 (11) ◽

pp. 2828

Author(s):

Soongeun Kwon ◽

Hak-Jong Choi ◽

Hyung Cheoul Shim ◽

Yeoheung Yoon ◽

Junhyoung Ahn ◽

...

Keyword(s):

High Performance ◽

Thermal Reaction ◽

Graphitic Carbon ◽

Direct Laser Writing ◽

Laser Writing ◽

Experimental Conditions ◽

Laser Pyrolysis ◽

Direct Laser ◽

On Chip ◽

Carbon Dioxide Co2

We report a laser-pyrolyzed carbon (LPC) electrode prepared from a black photoresist for an on-chip microsupercapacitor (MSC). An interdigitated LPC electrode was fabricated by direct laser writing using a high-power carbon dioxide (CO2) laser to simultaneously carbonize and pattern a spin-coated black SU-8 film. Due to the high absorption of carbon blacks in black SU-8, the laser-irradiated SU-8 surface was directly exfoliated and carbonized by a fast photo-thermal reaction. Facile laser pyrolysis of black SU-8 provides a hierarchically macroporous, graphitic carbon structure with fewer defects (ID/IG = 0.19). The experimental conditions of CO2 direct laser writing were optimized to fabricate high-quality LPCs for MSC electrodes with low sheet resistance and good porosity. A typical MSC based on an LPC electrode showed a large areal capacitance of 1.26 mF cm−2 at a scan rate of 5 mV/s, outperforming most MSCs based on thermally pyrolyzed carbon. In addition, the results revealed that the high-resolution electrode pattern in the same footprint as that of the LPC-MSCs significantly affected the rate performance of the MSCs. Consequently, the proposed laser pyrolysis technique using black SU-8 provided simple and facile fabrication of porous, graphitic carbon electrodes for high-performance on-chip MSCs without high-temperature thermal pyrolysis.

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On-chip Direct Laser Writing of PAN-based Carbon Supercapacitor Electrodes

10.33774/chemrxiv-2021-z4811 ◽

2021 ◽

Author(s):

Andreas Hoffmann ◽

Pablo Jiménez-Calvo ◽

Volker Strauss ◽

Alexander Kühne

Keyword(s):

Laser Power ◽

Printed Circuit Board ◽

Circuit Board ◽

Carbon Electrodes ◽

Direct Laser Writing ◽

Laser Writing ◽

Printed Circuit ◽

Direct Laser ◽

On Chip

We report carbonization of polyacrylonitrile by direct laser writing to produce microsupercapacitors directly on-chip. We demonstrate the process by producing interdigitated carbon finger electrodes directly on a printed circuit board, which we then employ to characterize our supercapacitor electrodes. By varying the laser power, we are able to tune the process from carbonization to material ablation. This allows to not only convert pristine polyacrylonitrile films into carbon electrodes, but also to pattern and cut away non-carbonized material to produce completely freestanding carbon electrodes. While the carbon electrodes adhere well to the printed circuit board, non-carbonized polyacrylonitrile is peeled off the substrate. We achieve specific capacities as high as 260 µF/cm2 in a supercapacitor with 16 fingers.

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Exploiting Direct Laser Writing for Hydrogel Integration into Fragile Microelectromechanical Systems

Sensors ◽

10.3390/s19112494 ◽

2019 ◽

Vol 19 (11) ◽

pp. 2494

Author(s):

Julian Menges ◽

Steffen Klingel ◽

Egbert Oesterschulze ◽

Hans-Jörg Bart

Keyword(s):

High Precision ◽

Microelectromechanical Systems ◽

Polymer Composition ◽

Linear Polymers ◽

Lateral Size ◽

Proof Of Concept ◽

Direct Laser Writing ◽

Laser Writing ◽

Direct Laser ◽

Responsive Hydrogels

The integration of chemo-responsive hydrogels into fragile microelectromechanical systems (MEMS) with reflective surfaces in the micron to submicron range is presented. Direct laser writing (DLW) for 3D microstructuring of chemoresponsive “smart” hydrogels on sensitive microstructures is demonstrated and discussed in detail, by production of thin hydrogel layers and discs with a controllable lateral size of 2 to 5 µm and a thickness of some hundred nm. Screening results of polymerizing laser settings for precision microstructuring were determined by controlling crosslinking and limiting active chain diffusion during polymerization with macromers. Macromers are linear polymers with a tunable amount of multifunctional crosslinker moieties, giving access to a broad range of different responsive hydrogels. To demonstrate integration into fragile MEMS, the gel was deposited by DLW onto a resonator with a 200 nm thick sensing plate with high precision. To demonstrate the applicability for sensors, proof of concept measurements were performed. The polymer composition was optimized to produce thin reproducible layers and the feasibility of 3D structures with the same approach is demonstrated.

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