Efficiency Enhancement of Organic Solar Cells by Fabricating Periodic Surface Textures using Direct Laser Interference Patterning

2012 ◽  
Vol 24 (7) ◽  
pp. 906-910 ◽  
Author(s):  
Lars Müller-Meskamp ◽  
Yong Hyun Kim ◽  
Teja Roch ◽  
Simone Hofmann ◽  
Reinhard Scholz ◽  
...  
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Efficiency Enhancement ◽  
Laser Interference ◽  
Periodic Surface ◽  
Surface Textures ◽  
Direct Laser ◽  
Direct Laser Interference Patterning

scholarly journals Picosecond Laser Interference Patterning of Periodical Micro-Architectures on Metallic Molds for Hot Embossing

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3409 ◽  
Author(s):  
Yangxi Fu ◽  
Marcos Soldera ◽  
Wei Wang ◽  
Bogdan Voisiat ◽  
Andrés Fabián Lasagni
Keyword(s):  
Picosecond Laser ◽  
Processing Parameters ◽  
Hot Embossing ◽  
Surface Structures ◽  
Laser Source ◽  
Laser Interference ◽  
Periodic Surface ◽  
Direct Laser ◽  
Direct Laser Interference Patterning ◽  
532 Nm

In this work, it is demonstrated that direct laser interference patterning (DLIP) is a method capable of producing microtextured metallic molds for hot embossing processes. Three different metals (Cr, Ni, and Cu), relevant for the mold production used in nanoimprinting systems, are patterned by DLIP using a picosecond laser source emitting at a 532 nm wavelength. The results show that the quality and surface topography of the produced hole-like micropatterns are determined by the laser processing parameters, such as irradiated energy density and the number of pulses. Laser-induced periodic surface structures (LIPSS) are also observed on the treated surfaces, whose shapes, periodicities, and orientations are strongly dependent on the accumulated fluence. Finally, the three structured metals are used as embossing molds to imprint microlenses on polymethyl methacrylate (PMMA) foils using an electrohydraulic press. Topographical profiles demonstrate that the obtained structures are comparable to the masters showing a satisfactory reproduction of the texture. The polymeric microlens arrays that showed the best surface homogeneity and overall quality were those embossed with the Cr molds.

scholarly journals Avoiding Starvation in Tribocontact Through Active Lubricant Transport in Laser Textured Surfaces

Lubricants ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 54 ◽  
Author(s):  
Tobias Stark ◽  
Thomas Kiedrowski ◽  
Holger Marschall ◽  
Andrés Fabián Lasagni
Keyword(s):  
Fluid Transport ◽  
Dynamical Behavior ◽  
Second Step ◽  
Textured Surfaces ◽  
Laser Interference ◽  
Narrow Channels ◽  
Surface Textures ◽  
Direct Laser ◽  
Direct Laser Interference Patterning ◽  
Limited Depth

Laser texturing is a viable tool to enhance the tribological performance of surfaces. Especially textures created with Direct Laser Interference Patterning (DLIP) show outstanding improvement in terms of reduction of coefficient of friction (COF) as well as the extension of oil film lifetime. However, since DLIP textures have a limited depth, they can be quickly damaged, especially within the tribocontact area, where wear occurs. This study aims at elucidating the fluid dynamical behavior of the lubricant in the surroundings of the tribocontact where channel-like surface textures are left after the abrasion wear inside the tribocontact area. In a first step, numerical investigations of lubricant wetting phenomena are performed applying OpenFOAM®. The results show that narrow channels (width of 10 μ m ) allow higher spreading than wide channels (width of 30 μ m ). In a second step, fluid transport inside DLIP textures is investigated experimentally. The results show an anisotropic spreading with the spreading velocity dependent on the period and depth of the laser textures. A mechanism is introduced for how lubricant can be transported out of the channels into the tribocontact. The main conclusion of this study is that active lubricant transport in laser textured surfaces can avoid starvation in the tribocontact.

scholarly journals Laser Fabrication of Anti-Icing Surfaces: A Review

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5692
Author(s):  
Annalisa Volpe ◽  
Caterina Gaudiuso ◽  
Antonio Ancona
Keyword(s):  
Review Article ◽  
Ice Formation ◽  
Direct Laser Writing ◽  
Laser Interference ◽  
Comprehensive Overview ◽  
Periodic Surface ◽  
Starting Point ◽  
Direct Laser ◽  
Polymeric Substrates ◽  
Direct Laser Interference Patterning

In numerous fields such as aerospace, the environment, and energy supply, ice generation and accretion represent a severe issue. For this reason, numerous methods have been developed for ice formation to be delayed and/or to inhibit ice adhesion to the substrates. Among them, laser micro/nanostructuring of surfaces aiming to obtain superhydrophobic behavior has been taken as a starting point for engineering substrates with anti-icing properties. In this review article, the key concept of surface wettability and its relationship with anti-icing is discussed. Furthermore, a comprehensive overview of the laser strategies to obtain superhydrophobic surfaces with anti-icing behavior is provided, from direct laser writing (DLW) to laser-induced periodic surface structuring (LIPSS), and direct laser interference patterning (DLIP). Micro-/nano-texturing of several materials is reviewed, from aluminum alloys to polymeric substrates.

Fabrication of hierarchical surface textures using multi-pulse direct laser interference patterning with nanosecond pulses

2020 ◽  
Vol 258 ◽  
pp. 126743 ◽  
Author(s):  
Mikhael El-Khoury ◽  
Sabri Alamri ◽  
Bogdan Voisiat ◽  
Tim Kunze ◽  
Andrés Fabián Lasagni
Keyword(s):  
Laser Interference ◽  
Surface Textures ◽  
Nanosecond Pulses ◽  
Direct Laser ◽  
Direct Laser Interference Patterning
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