Laser Printing of Functional Materials E-Book
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- Herausgeber: Wiley-VCH Verlag GmbH & Co. KGaA
- Kategorie: Fachliteratur
- Sprache: Englisch
The first book on this hot topic includes such major research areas as printed electronics, sensors, biomaterials and 3D cell printing.
Well-structured and with a strong focus on applications, the text is divided in three sections with the first describing the fundamentals of laser transfer. The second provides an overview of the wide variety of materials that can be used for laser transfer processing, while the final section comprehensively discusses a number of practical uses, including printing of electronic materials, printing of 3D structures as well as large-area, high-throughput applications. The book is rounded off by a look at the future for laser printed materials.
Invaluable reading for a broad audience ranging from material developers to mechanical engineers, from academic researchers to industrial developers and for those interested in the development of micro-scale additive manufacturing techniques.
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Veröffentlichungsjahr: 2017
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Table of Contents
Cover
Title Page
Copyright
Preface
Part I: Fundamentals
Chapter 1: Introduction to Laser-Induced Transfer and Other Associated Processes
1.1 LIFT and Its Derivatives
1.2 The Laser Transfer Universe
1.3 Book Organization and Chapter Overview
1.4 Looking Ahead
Acknowledgments
References
Chapter 2: Origins of Laser-Induced Transfer Processes
2.1 Introduction
2.2 Early Work in Laser-Induced Transfer
2.3 Overview of Laser-Induced Forward Transfer
2.4 Other Laser-Based Transfer Techniques Inspired by LIFT
2.5 Other Studies on LIFT
2.6 Conclusions
References
Chapter 3: LIFT Using a Dynamic Release Layer
3.1 Introduction
3.2 Absorbing Release Layer – Triazene Polymer
3.3 Front- and Backside Ablation of the Triazene Polymer
3.4 Examples of Materials Transferred by TP-LIFT
3.5 First Demonstration of Devices: OLEDs and Sensors
3.6 Variation of the DRL Approach: Reactive LIFT
3.7 Conclusions and Perspectives
3.8 Acknowledgments
Conflict of Interest
References
Chapter 4: Laser-Induced Forward Transfer of Fluids
4.1 Introduction to the LIFT of Fluids
4.2 Mechanisms of Fluid Ejection and Deposition
4.3 Printing Droplets through LIFT
4.4 Printing Lines and Patterns with LIFT
4.5 Summary
Acknowledgments
References
Chapter 5: Advances in Blister-Actuated Laser-Induced Forward Transfer (BA-LIFT)
5.1 Introduction
5.2 BA-LIFT Basics
5.3 Why BA-LIFT?
5.4 Blister Formation
5.5 Jet Formation and Expansion
5.6 Application to the Transfer of Delicate Materials
5.7 Conclusions
References
Chapter 6: Film-Free LIFT (FF-LIFT)
6.1 Introduction
6.2 Rheological Considerations in Traditional LIFT of Liquids
6.3 Fundamentals of Film-Free LIFT
6.4 Implementation and Optical Considerations
6.5 Applications
6.6 Conclusions and Future Outlook
References
Part II: The Role of the Laser–Material Interaction in LIFT
Chapter 7: Laser-Induced Forward Transfer of Metals
7.1 Introduction, Background, and Overview
7.2 Modeling, Simulation, and Experimental Studies of the Transfer Process
7.3 Advanced Modeling of LIFT
7.4 Research Needs and Future Directions
7.5 Conclusions
References
Chapter 8: LIFT of Solid Films (Ceramics and Polymers)
8.1 Introduction
8.2 Assisted Release Processes
8.3 Shadowgraphy Studies and Assisted Capture
8.4 Applications in Energy Harvesting
8.5 Laser-Induced Backward Transfer (LIBT) of Nanoimprinted Polymer
8.6 Conclusions
Acknowledgments
References
Chapter 9: Laser-Induced Forward Transfer of Soft Materials
9.1 Introduction
9.2 Background
9.3 Jetting Dynamics during Laser Printing of Soft Materials
9.4 Laser Printing Applications Using Optimized Printing Conditions
9.5 Conclusions and Future Work
Acknowledgments
References
Chapter 10: Congruent LIFT with High-Viscosity Nanopastes
10.1 Introduction
10.2 Congruent LIFT (or LDT)
10.3 Applications
10.4 Achieving Congruent Laser Transfers
10.5 Issues and Challenges
10.6 Summary
Acknowledgment
References
Chapter 11: Laser Printing of Nanoparticles
11.1 Introduction, Setup, and Motivation
11.2 Laser-Induced Transfer
11.3 Materials for Laser Printing of Nanoparticles
11.4 Laser Printing from Bulk-Silicon and Silicon Films
11.5 Magnetic Resonances of Silicon Particles
11.6 Laser Printing from Prestructured Films
11.7 Applications: Sensing, Metasurfaces, and Additive Manufacturing
11.8 Outlook
References
Part III: Applications
Chapter 12: Laser Printing of Electronic Materials
12.1 Introduction and Context
12.2 Organic Thin-Film Transistor
12.3 Organic Light-Emitting Diode
12.4 Passive Components
12.5 Interconnection and Heterogeneous Integration
12.6 Conclusion
References
Chapter 13: Laser Printing of Chemical and Biological Sensors
13.1 Introduction
13.2 Conventional Printing Methods for the Fabrication of Chemical and Biological Sensors
13.3 Laser-Based Printing Techniques: Introduction
13.4 Applications of Direct Laser Printing
13.5 Conclusions
References
Chapter 14: Laser Printing of Proteins and Biomaterials
14.1 Introduction
14.2 LIFT of DNA in Solid and Liquid Phase
14.3 LIFT of Biomolecules
14.4 Conclusions and Perspectives
Acknowledgments
Conflict of Interest
References
Chapter 15: Laser-Assisted Bioprinting of Cells for Tissue Engineering
15.1 Laser-Assisted Bioprinting of Cells
15.2 Laser-Assisted Bioprinting for Cell Biology Studies
15.3 Laser-Assisted Bioprinting for Tissue-Engineering Applications
15.4 Conclusion
References
Chapter 16: Industrial, Large-Area, and High-Throughput LIFT/LIBT Digital Printing
16.1 Introduction
16.2 Potential Markets and their Technical Demands on Lasersonic® LIFT
16.3 Lasersonic® LIFT/LIBT Printing Method
16.4 Optical Concept and Pulse Control of the Lasersonic® Printing Machine
16.5 The Four-Color Lasersonic® Printing Machine
16.6 Print Experiments and Results
16.7 Discussion of Effects
16.8 Future Directions
16.9 Summary
Acknowledgments
References
Chapter 17: LIFT of 3D Metal Structures
17.1 Introduction
17.2 Basic Aspects of LIFT of Metals for 3D Structures
17.3 Properties of LIFT-Printed Freestanding Metal Pillars
17.4 Demonstrators and Potential Applications
17.5 Conclusions and Outlook
References
Chapter 18: Laser Transfer of Entire Structures and Functional Devices
18.1 Introduction
18.2 Early Demonstrations of LIFT of Entire Structures
18.3 Process Dynamics
18.4 Laser Transfer of Intact Structures
18.5 Laser Transfer of Components for Embedded Electronics
18.6 Outlook
18.7 Summary
Acknowledgments
References
Index
End User License Agreement
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Guide
Cover
Table of Contents
Preface
Part I: Fundamentals
Begin Reading
List of Illustrations
Chapter 1: Introduction to Laser-Induced Transfer and Other Associated Processes
Figure 1.1 Principle of operation of the LIFT technique.
Chapter 2: Origins of Laser-Induced Transfer Processes
Figure 2.1 (a) Forward transfer, in contact, (b) forward transfer across a gap, (c) reverse transfer, in contact, (d) reverse transfer across a gap.
Figure 2.2 Conventional laser-induced forward transfer (LIFT) method.
Figure 2.3 Dynamic release layer (DRL)-assisted LIFT method.
Figure 2.4 Scanning electron micrograph of a computer-generated holographic complex pixelated pattern produced by the deposition from a 400 nm thick chromium donor layer of Cr deposit features of about 3 µm × 3 µm.
Figure 2.5 Scanning electron micrograph of a computer-generated multilevel computer-generated holographic structure on glass, comprising three layers of Cr selectively deposited on appropriate areas on a glass plate.
Figure 2.6 Schematic of LP-LIFT. Donor is annealed to the receiver.
Figure 2.7 Schematic of LP-LIFT. Donor and receiver substrates are separated and the annealed regions remain to the receiver.
Chapter 3: LIFT Using a Dynamic Release Layer
Figure 3.1 Chemical structure of the triazene polymer, which was used for most LIFT experiments.
Figure 3.2 UV–vis absorption spectrum of a typical triazene polymer thin film, spin coated from chlorobenzene:cyclohexanone (1 : 1) solution.
Figure 3.3 Schematic drawing of (a) backside ablation of a triazene polymer layer and (b) front-side ablation of a triazene polymer layer.
Figure 3.4 Sequence of photos taken for (a) front-side ablation of a 500 nm triazene polymer film at 110 mJ/cm
2
laser fluence; (b) backside ablation of a 460 nm triazene polymer film at 110 mJ/cm
2
laser fluence.
Figure 3.5 (a) Sequence of pictures taken for backside ablation of a PS-microbead pixel on top of a 100 nm thick triazene polymer layer at 1.5 J/cm
2
laser fluence. (b) SEM image of a PS-microbead pixel transferred at 2.25 J/cm
2
laser fluence. (c) SEM image of the surface morphology of the PS-microbeads transferred at 1.5 J/cm
2
laser fluence.
Figure 3.6 (a) Scheme of the device architecture with two electrodes (ITO anode and Al cathode) and the MEH-PPV light-emitting layer. (b) Al/MEH-PPV transferred onto the ITO substrate. (c) Image of the successful operation of one of the transferred devices.
Figure 3.7 (a) Scheme of the TP-LIFT for fabricating an OLED pixel/device. (b) Electroluminescence from two LIFTed devices with the architecture ITO/PEDOT:PSS/MEH-PPV:PEO/Al. The light-emitting section of the diodes is the lower half, where the aluminum cathode overlaps with the ITO anode.
Figure 3.8 (a) Optical microscopy images of PIB (bottom), PECH (middle), and PEI (top) polymers transferred by LIFT onto two-port SAW devices. Dinca
et al
. 2013 [72]. Reproduced with permission from Romanian Reports in Physics.) (b) Schematic drawing of the SMR (left side) and optical microscopy images of SMR devices coated with PEI polymer deposited at 400 mJ/cm
2
(left) and 300 mJ/cm
2
(right) laser fluence.
Figure 3.9 (a) Time response of the three SAW sensors for two concentrations of EtOAc. (b) Response curve for PECH, PEI, and PIB sensors upon exposure to different concentrations of DMMP. (Di Pietrantonio
et al
. 2012 [54]. Reproduced with permission of Elsevier.) (c) Frequency response of an SMR before and after deposition of 13 nm thick PECH film. (d) Response curves of coated SMR sensors (PEI, PIB, and PECH polymers) for DMMP.
Figure 3.10 UV–vis absorption spectrum of a typical SnCl
2
(acac)
2
thin film with a thickness of 900 nm. Inset: Chemical structure of SnCl
2
(acac)
2
.
Figure 3.11 (a) SnO
2
rLIFTed pixel onto a commercial Microsens semiconductor gas sensor (MSGS) structure. (b) Sensor responses to 5 ppm of ethanol (at 350 °C) and 15 ppm of methane (at 500 °C).
Chapter 4: Laser-Induced Forward Transfer of Fluids
Figure 4.1 Sketch of a LIFT setup for printing fluids from a donor film onto a receiving substrate.
Figure 4.2 Stop-action movie of the dynamics of long and stable jet formation in LIFT at different delay times with respect to the laser pulse. The corresponding delay time is indicated above each image, and the image exposure time is always 100 ns. In all of the frames, the laser impinges from above. The transferred solution corresponds to a mixture of water and glycerol.
Figure 4.3 Stop-action movie of the jetting dynamics corresponding to a LIFT event with insufficient laser pulse energy for transfer to occur. The jet retracts before reaching the receiving substrate. The corresponding delay time after the laser pulse is indicated above each image, and the image exposure time is always 100 ns. In all of the frames, the laser impinges from above. The transferred solution corresponds to a mixture of water and glycerol.
Figure 4.4 Stop-action movie of the transfer dynamics corresponding to a LIFT event with excessive laser pulse energy. The bubble bursts before the jet can develop, which results in undesired splashing on the receiving substrate. The corresponding delay time after the laser pulse is indicated above each image, and the image exposure time is always 100 ns. In all of the frames, the laser impinges from above. The transferred solution corresponds to a commercial silver ink.
Figure 4.5 Stop-action movie of the jetting dynamics corresponding to a LIFT event resulting in the formation of circular sessile droplets. It can be observed that transfer proceeds through the contact of the jet with the receiving substrate. The corresponding delay time after the laser pulse is indicated above each image, and the image exposure time is always 100 ns. In all of the frames, the laser impinges from above. The transferred solution corresponds to a mixture of water and glycerol.
Figure 4.6 Stop-action movie of the dynamics corresponding to a LIFT event resulting in the formation of circular sessile droplets through contact of the expanding bubble with the receiving substrate. The corresponding delay time after the laser pulse is indicated above each image, and the image exposure time is always 100 ns. In all of the frames, the laser impinges from above. The transferred solution corresponds to a commercial silver ink.
Figure 4.7 Optical microscopy image of LIFT-printed droplets of silver nanoparticles ink for different energies from (a) Ag NPs ink/quartz donor substrate, (b) Ag NPs ink/Ti/quartz donor substrate.
Figure 4.8 Plot of the transferred droplet volume versus laser pulse energy for a water and glycerol solution deposited with different laser beam dimensions (ω
x
and ω
y
correspond to the major and minor radii of an elliptical laser beam): (○) ω
x
= ω
y
= 11 µm; (▪) ω
x
= 31 µm, ω
y
= 25 µm; (∇) ω
x
= 51 µm, ω
y
= 36 µm; (•) ω
x
= 73 µm, ω
y
= 47 µm; (□) ω
x
= 95 µm, ω
y
= 64 µm; (
–
) linear fit. The insert corresponds to a magnification of the points corresponding to the smallest beam dimensions.
Figure 4.9 Cross section of the three-dimensional plot of the local fluence function along the
fluence-x
plane for a laser pulse in which the fluence peak is higher than
F
o
. (a) The volume corresponding to the shaded area equals
E
−
E
o
, and the dashed line corresponds to a laser pulse of total energy equal to
E
o
. (b) The volume corresponding to the shaded area equals
E
eff
.
Figure 4.10 Plot of the droplet volume versus
E
eff
for the results in Figure 4.8 corresponding to the LIFT of a water and glycerol solution with the following laser beam radii: (□) ω
x
= 31 µm, ω
y
= 25 µm; (▾) ω
x
= 51 µm, ω
y
= 36 µm; (•) ω
x
= 73 µm, ω
y
= 47 µm; (▪) ω
x
= 95 µm, ω
y
= 64 µm; (
–
) linear fit.
Figure 4.11 Plot of the droplet diameter as a function of glycerol concentration of water–glycerol solutions deposited by LIFT with spot diameter of 150 µm of an ArF excimer laser.
Figure 4.12 Optical microscope image of a microarray of droplets obtained through LIFT at constant laser pulse energy and at different donor–receiver gaps. The separation distance is indicated on the left, in micrometers. The transferred solution corresponds to a mixture of water and glycerol.
Figure 4.13 Optical microscopy image of (a) LIFT-printed droplets of a water–glycerol solution at different separation distance, Δ
x
, and (b) 2 mm uniform line printed at 40 µm droplet separation distance; inset: area of the uniform line printed at 40 µm droplet spacing. Printing direction is (a) from top to bottom, and (b) from left to right. The transferred solution corresponds to a mixture of water and glycerol. Scale bar is 100 µm.
Figure 4.14 (a) Optical microscopy image of LIFT-printed AgNP electrodes on PI with 70 µm width and 2 mm length. (Zacharatos
et al
. 2016 [100]. Reproduced with permission of Elsevier.) (b) Image of sample consisting of 21 pairs of electrodes with spacing between electrode pairs of 50, 100, and 200 µm. (Zacharatos
et al
. 2016 [100]. Reproduced with permission of Elsevier.) (c) SEM image of a pentacene TFT with top-contact geometry (
L
= 10 µm,
W
= 1000 µm). The electrodes were printed with LIFT [97]. The pentacene layer corresponds to the area enclosed by the broken-line square. S represents the source, D represents the drain, and G represents the gate.
Chapter 5: Advances in Blister-Actuated Laser-Induced Forward Transfer (BA-LIFT)
Figure 5.1 (A) Laser-induced forward transfer utilizing a polymer laser-absorbing layer: (a) the laser is absorbed within a thin layer of the polymer film, (b) ablating a confined pocket of gas and forcing the remaining film away from the glass as a rapidly expanding blister. If the impulse provided by the blister is sufficient, a small volume of ink is ejected onto an acceptor substrate [15]. (B) Transfers from a 10 m film of NMP spread on 6 m polyimide film initiated with a 20 m beam at 1.3 J/cm fluence. The vertical field of view is 200 m, and the bars indicate the beam size and location [16].
Figure 5.2 Mechanisms for laser-induced actuation of flow within the ink film. (a) Laser absorption within a Ti film that results in vaporization of the solvents in adjacent ink. (b) Laser absorption within a PI layer produces an expanding, sealed blister. (c) Laser absorption within a PI layer causes its rupture and releases high-pressure gases.
Figure 5.3 Time-resolved images of liquid ejection into the ambient air using a 50 nm titanium-absorbing layer. A 1.6 J laser pulse is focused into the titanium film to a spot size of 2.5 m (indicated by a white marker), initiating liquid ejection from an adjacent 5 m film [12]. Fluid motion is initiated by focusing a 1.6 J laser pulse into the titanium layer to a 2.5 m Gaussian spot. This value is observed to be the threshold value for 5 m liquid donor film using a nm titanium metal absorber layer. The ink used in this study consists of an aqueous solution of glycerol ( v/v) with Triton X-100 surfactant ( v/v), a solution commonly employed in the literature [31, 32].
Figure 5.4 (a) Initial configuration of the problem. (b) Schematic of the re-entrant jet with vapor cavity. Close-up experimental images acquired at 5 s of gas cavities formed during the ejection of liquid from a 5 m film using (c) titanium (11.8 J) and (d) polyimide (7.3 J) absorbing layers with a 2.5 m beam. Internal re-entrant jets (directed upwards) are clearly visible within the gas cavity [36].
Figure 5.5 Time-resolved images of liquid jets expelled into the ambient air using a 7 m expanded polyimide-absorbing layer. A 2.7 J laser pulse is focused into the polyimide film to a spot size of 10 m (indicated by a white marker), producing a rapidly expanding, sealed blister, which initiates liquid ejection from an adjacent 5 m film. The vertical field of view is 200 m. An image (1 s) of the blister, rinsed with residual liquid.
Figure 5.6 (a) Time response of blisters formed on 3.5 m thick polyimide film with a 20 m top hat beam (2.6 J/cm). (b) Time response of blisters formed on 6 m thick polyimide film with a 20 m top hat beam (4.3 J/cm). In these cases, a 10 m -methyl-2-pyrrolidone (NMP) ink is used. (Top) Volume and surface area versus time. Error bars indicate the 1 standard deviation in the values. (Bottom) Sample images of the blisters at several times. The bar indicates the 20 m beam diameter.
Figure 5.7 (a) Evolution of blister height during the initial period of rapid expansion. An overshoot and oscillation are visible in the blisters formed with a 20 m beam. The effect is more pronounced with the thinner film. Steady-state blister heights are shown for reference. (b) Blister height versus laser fluence for different combinations of film thickness and beam size. The vertical dashed lines indicate the blister rupture fluence for each case.
Figure 5.8 (a) Images of blisters formed at several fluences for different combinations of film thickness and beam size. The bars indicate the beam diameter (10 or 20 m). (b) Blisters formed on 6 m polyimide film with a 20 m beam (4.3 J/cm) with and without a 10 m liquid film of NMP. (Top) Blister volume as a function of fluence for blisters formed with and without an ink layer. Both curves overlap significantly indicating the minimal effect of the ink layer on the blister size. (Bottom) No noticeable difference in the shape between blisters formed with and without a liquid layer. The bars indicate the 20 m beam diameter.
Figure 5.9 (a) Optical microscopy images of laser-transferred droplets taken at 5, 7, 11, and 31 J from left to right. (b) Associated microscopy images of polyimide film. (c) SEM images of polyimide film taken at an angle of 70.
Figure 5.10 (a) Parameter map evaluated to find and to evaluate the dynamic flow stress, , by choosing the values that yield the minimum average residual sum of squares (RSS). (b) The blister formation as evaluated via finite element simulations. The parameter is varied to equate the numerically evaluated blister height to the experimental result [43]. Dashed lines denote the experimental profile, whereas solid lines denote the fitted blister profiles.
Figure 5.11 Results from the empirical formula for blister profile. (a) The normalized temporal evolution of blister height initiated with a 14.9 J laser pulse. Each data point represents the average of five measurements, and the vertical bars indicate 1 standard deviation. A fit is also shown on the plot. (b) Experimentally measured blister profiles (solid lines) shown with their associated fits (dashed lines).
Figure 5.12 (a) Experimentally acquired images and (b) rendered computational results of fluid ejections from a 5 m donor film of NMP using a 5.4 J laser pulse. The ejected fluid volume extracted from the last experimental image (1.2 10 m ) compares favorably with that from the simulated ejection (1.0 10 m ). Image frames are 134 m high. (c) Experimentally acquired image of a jet ejected from a 5 m donor film of NMP-acquired 8 s after a 7.7 J laser pulse. The jet impacts with an acceptor substrate (glass slide) located 150 m below the donor substrate. (d) Rendered image of a simulated ejection at 8 s corresponding to the experimental conditions. A 45 contact angle is imposed at the acceptor–substrate boundary to match the experiment.
Figure 5.13 Plot of experimentally measured and simulated volumes of ink transferred as a function of laser energy. Each experimental data point represents the average of volumes measured from 10 transferred droplets, and the vertical error bars indicate the 1 standard deviation. The horizontal error bars indicate the 1 standard deviation in the shot-to-shot variation of laser energy.
Figure 5.14 Simulation results for blister-actuated flows using standard ink properties initiated with laser energy inputs of: (a) J (below threshold), (b) J (transfer threshold), (c) J (below second threshold), (d) J (impact with acceptor).
Figure 5.15 Results of the numerical parametric studies. Transferred volume and threshold energy values with varying parameters are presented.
Figure 5.16 Variations of LIFT. (a) Absorption directly within the ink. (b) Laser absorption within a metal-film absorbing layer results in vaporization of the adjacent ink, producing a high-pressure vapor cavity. (c) Laser absorption within a polymer-film absorbing layer produces a rapidly expanding, sealed blister [36].
Figure 5.17 Photoluminescence spectra of (a) AM showing significant damage when printed via DMA (1 J/cm) but no apparent damage using either metal-film absorber (MFA) (0.375 J/cm) or polymer-film absorber (PFA or BA-LIFT) (0.75 J/cm). An undamaged spectrum of (b) Alq material printed via DMA transferred at higher fluences can be seen for the Alq molecule.
Figure 5.18 NMR spectra of AM for (a) control and printed using (b) BA-LIFT, (c) titanium DRL, and (d) direct-matrix absorption. Arrows indicate the degradation products present in the corresponding techniques. No peaks exist in control or polymer absorptive layer.
Figure 5.19 (a) Image of the LED (12.5 12.5 mm) under room light illumination. (b) Device operation under ambient conditions depicting two 2.5 2.5 mm orange–red pixels. (c) Posttransfer PL and device EL match the pretransfer solution PL.
Chapter 6: Film-Free LIFT (FF-LIFT)
Figure 6.1 Scheme of traditional LIFT of liquids (a) and film-free LIFT (b).
Figure 6.2 Sketch of spontaneous (a) and externally induced (b) instabilities that can affect the spatiotemporal uniformity of a thin liquid donor film.
Figure 6.3 Schematic representation of the main existing technologies for the preparation of thin liquid films: (a) spin coating, (b) dip coating, and (c) blade coating.
Figure 6.4 Investigation of the dynamics of FF-LIFT. Time-resolved images depicting the cavitation formation and jet evolution in a solution of water and glycerol, for (grayscale images) (Patrascioiu
et al
. 2014 [60]. Reproduced with permission of Springer.) and numerical simulations of the same process depicting the pressure map and velocity field.
Figure 6.5 Schematic of two different implementations of FF-LIFT. (a) Inverted or forward configuration and (b) upright or backward configuration.
Figure 6.6 Applications of FF-LIFT (a) Fluorescence image of a fabricated biosensors consisting of a microarray of mouse IgG and rabbit IgG after immunoassay with specific anti-IgG. The inset shows an optical microscopy image of the same array. (Duocastella
et al
. 2010 [39]. Reproduced from Elsevier.) (b) Laser printing applied to the realization of polymeric microlenses. Scanning electronic microscopy (SEM) images of polymer microlenses fabricated on (i) polydimethylsiloxane and (ii) glass. (iii) SEM image of a star-shaped pattern of microlenses. (iv) Optical microscopy image of the surface of a CD (line pitch 1.6 µm) without and with the microlens on top. In the latter, the lines of the CD can be observed, which demonstrates the effective enhancement in the resolution of the system.
Chapter 7: Laser-Induced Forward Transfer of Metals
Figure 7.1 Schematic of LIFT of metals including laser heating, transfer, and deposition on a target substrate. The focused laser spot locally heats the metal film at the interface with a transparent donor substrate. The metal is energized at the laser focal spot, propelled across a gap, and deposited on a target substrate.
Figure 7.2 Absorption of laser energy in the metal donor film showing the confinement of the absorbed laser energy at the interface between the donor substrate and the film. The relative sizes of the film thickness,
t
, thermal diffusion length,
L
th
, and optical absorption depth,
L
opt
, are critical to the behavior of the LIFT process.
Figure 7.3 First LIFT results reported by Bohandy
et al
. [1] showing copper lines deposited on a silicon target using a 193 nm, 15 ns excimer laser. At low pulse energy, the deposited lines were not consistent. As the laser pulse energy increased, the line quality and uniformity improved. However, at the highest energy, the resolution was degraded due to spreading of the deposited material.
Figure 7.4 SEM images showing results of nanosecond LIFT of aluminum. (a) Aluminum microdroplets transferred to a glass target substrate (scale bar is 1 µm) [66]. Each droplet resulted from a single laser pulse. (b) Aluminum donor film after laser irradiation below the transfer threshold, showing droplets which did not leave the donor. (c) Closeup view of one of the droplets from the upper right of image (b) showing a resolidified jet with a droplet on top (scale bar is 100 nm).
Figure 7.5 Images showing transferred droplet (a) and donor film (b) after LIFT. The donor film shows a crater from which the droplet was removed, rather than a jetting mechanism observed in other studies.
Figure 7.6 Transfer regimes of LIFT as a function of timescale and fluence.
Chapter 8: LIFT of Solid Films (Ceramics and Polymers)
Figure 8.1 Schematic showing possible interference effects in the LIFT process.
Figure 8.2 Simulated intensity profiles from a circular aperture of diameter 10 µm, for 800 nm light, for distances of (a) 0 nm, (b) 250 nm, (c) 500 nm, and (d) 1000 nm.
Figure 8.3 BLAST technique for (a) donor thickness 80 nm, single pulse at 90% of fluence threshold, (b) donor thickness 80 nm, 10 pulses at 80% of fluence threshold, and (c) donor thickness 160 nm, 10 pulses at 87% of fluence threshold.
Figure 8.4 (a) Donor film, showing FIB machining of a circle of 80% depth of the donor film, and deposited zinc oxide material (b) not using and (c) using donor premachining.
Figure 8.5 Experimental setup for the DMD-based LIFT of polymer films.
Figure 8.6 SEM images of approximately 1.3 µm thick polymer film deposits of letters (“O,” “B,” and “S”) deposited via DMD-based LIFT using (a–c) 50× objective and (d–f) 20× objective.
Figure 8.7 SEM images of structured deposition (letter “A”), for fluences of (a) 235 mJ/cm
2
, (b) 251 mJ/cm
2
, (c) 268 mJ/cm
2
, (d) 284 mJ/cm
2
, and (e) 300 mJ/cm
2
.
Figure 8.8 Schematic showing shadowgraphy setup.
Figure 8.9 Shadowgraph images for 1 µm thick Yb:YAG donor for DRL thickness of 250 nm and fluence values of (a) 60 mJ/cm
2
and (b) 600 mJ/cm
2
. White scale bars are 500 µm.
Figure 8.10 Shadowgraph images for 1 µm thick Yb:YAG donor for a fluence value of 100 mJ/cm
2
and DRL thicknesses of (a) 50 nm and (b) 350 nm. White scale bars are 500 µm.
Figure 8.11 LIFT of 1 µm bismuth telluride with fluence 80 mJ/cm
2
for (a) uncoated glass, (b) 12 µm PDMS, (c) 100 µm PDMS, and (d) fluence 120 mJ/cm
2
, and 12 µm PDMS. The scale bars are 200 µm.
Figure 8.12 Microscope images of 1 µm thick bismuth telluride deposits for laser fluences of (a) 70 mJ/cm
2
, (b) 100 mJ/cm
2
, (c) 110 mJ/cm
2
, and (d) 200 mJ/cm
2
. Scale bars are 200 µm.
Figure 8.13 SEM images showing surfaces of bismuth telluride films of thicknesses (a) 270 nm, (b) 1 µm, and (c) 1.4 µm, before the LIFT process.
Figure 8.14 SEM images of (b) a side view of the 1 µm thick bismuth telluride deposit, with corresponding (a) bottom and (c) top surfaces. The laser irradiated the bottom surface.
Figure 8.15 Schematic showing deposition steps used for LIFT for device fabrication. Actual device was 20 leg pairs (19 junctions).
Figure 8.16 (a) Device schematic, (b) photo of fabricated device, and (c) image of n-type and p-type leg-pair contact.
Figure 8.17 Schematic of LIBT using an (a) unstructured and (b) structured carrier substrate.
Figure 8.18 SEM images of DMD-based pulse shaping for LIBT using an unstructured carrier, with S1813 donor with 1.4 µm thickness.
Figure 8.19 SEM images of (a) a region on a structured carrier feature, (b) LIBT deposition showing an inverted profile with central feature 140 nm wide and 220 nm high, (c) LIBT deposition showing an imprinted grating structure with fingers 900 nm wide and 220 nm high and (d) associated higher magnification image.
Chapter 9: Laser-Induced Forward Transfer of Soft Materials
Figure 9.1 Schematic of experimental setup.
Figure 9.2 Pluming/splashing regime images obtained using low glycerol concentration solutions: (a) 15%, (b) 25%, and (c) 35%, all of them at a laser fluence of 717 mJ/cm
2
.
Figure 9.3 Different time-resolved images of some jetting regimes (laser fluence of 717 mJ/cm
2
): (a) jetting with a bulgy shape when using 50% glycerol solution, (b) jetting with a bulgy shape when using 65% solution, (c) well-defined jetting when using 75% solution, (d) well-defined jetting when using 85% solution, and (e) no material transfer when using 99% solution.
Figure 9.4 Jetting regimes during LIFT under different laser fluences (65% glycerol solution).
Figure 9.5 Jetting regimes and characteristic timescale variations versus the dimensionless parameter
J
under a laser fluence of 717 mJ/cm
2
.
Figure 9.6 The influence of glycerol concentration and laser fluence on jet morphology and printability (dashed lines are for illustration only).
Figure 9.7 (a) Morphological features of a forming jet at 130 µs during printing 4% sodium alginate solution under a 1300 mJ/cm
2
laser fluence and representative images of the jet regimes: (b) pluming/splashing (6% alginate, 2300 mJ/cm
2
), (c) jetting with a bulgy shape (2% alginate, 1300 mJ/cm
2
), (d) well-defined jetting with an initial bulgy shape (4% alginate, 1500 mJ/cm
2
), (e) well-defined jetting (6% alginate, 1500 mJ/cm
2
), and (f) no material transfer (8% alginate, 1300 mJ/cm
2
).
Figure 9.8 Jet/droplet morphological evolution under a) different laser fluences when printing a 2% alginate solution and b) different alginate concentrations when using a 1300 mJ/cm
2
laser fluence. (The scale bar is 400 µm, and the dashed circle indicates the jet breakup moment as observed.)
Figure 9.9 (a) Jet velocity of different alginate solutions, (b) breakup time and breakup length (2% alginate), and (c) primary droplet size (2% alginate) as a function of laser fluence.
Figure 9.10 (a) Jet velocity as a function of alginate concentration, (b) breakup time and breakup length, and (c) size of the primary droplet size under a 1100 mJ/cm
2
laser fluence.
Figure 9.11 Different pinch-off locations for (a) 2% and (b) 4% alginate solutions.
Figure 9.12 Jetting regime as a function of (a)
We
,
Oh
, and
Ec
numbers, (b)
We
and
Oh
numbers, (c)
We
and
Ec
numbers, and (d)
Oh
and
Ec
numbers.
Figure 9.13 (a) Schematics of bifurcated construct printing (inset: a typical Y-shaped bifurcated structure), (b) representative images of Y-shaped alginate tubes printed using 8% sodium alginate solution (inset: different views of a printed Y-shaped alginate tube), and (c) Y-shaped cellular tubes printed with 2% alginate and 5 × 10
6
cells/ml bioink (left inset: different views of a printed Y-shaped cellular tube, and right inset: printed cells dyed in blue and living cells dyed in green).
Chapter 10: Congruent LIFT with High-Viscosity Nanopastes
Figure 10.1 SEM images of an array of (a) 5 µm and (b) 2 µm square voxels on silicon as transferred by LDT. Representative AFM 3D and height profiles are shown below each respective image. (c) SEM images of uncured silver voxels made by LDT showing wide range in voxel size, thickness, and shape. Each shape is printed from a single laser pulse.
Figure 10.2 Edge acuity of LDT lines and voxels. Panel (a) shows an AFM image of two parallel lines separated by 2 µm. Panel (b) shows SEM images of the change in edge acuity for different voxel thicknesses (white labels) as a function of voxel size (shown below each column).
Figure 10.3 SEM images of LDT arrays of 50 µm square voxels on Si with increasing donor-to-receiving substrate distance (transfer gap) and increasing voxel thickness. Voxels were “soft-cured” at less than 100 °C.
Figure 10.4 SEM images of self-supporting 3D stacks and a freestanding microbridge made by LDT without the use of any sacrificial layers.
Figure 10.5 Transfers produced by DMD-LDT. (a) Optical image of an annulus pattern loaded onto a DMD array and its spatial beam profile (inset). SEM images of silver nanopaste transfers on Si produced by (b) UV (λ = 355 nm) laser and (c–f) green (λ = 532 nm) laser pulses. The dotted square outlines the pattern printed by a single laser pulse. A single laser pulse was used to transfer each letter in (c) and the entire logo in (d). (e) A metamaterial surface printed with nine different laser shots. (f) SEM image of three interconnect patterns, each one printed with a single laser pulse by DMD-LDT using an edge-enhanced beam profile. (g) Optical image of one of the patterns in (f) printed over Au pads on a glass substrate. (h) Measured
IV
plot of one interconnect.
Figure 10.6 3D Ag interconnects fabricated by LDT with a (a–g) single voxel and (j) multiple voxels. (a,c) SEM images of LDT silver interconnects between an embedded LED die in polyimide to Au contact pads shown in the optical image (b). (d) LED Emission after oven curing at 150 °C and (e) after 500 bending cycles of 13 mm radius. (f) SEM image of an oven-cured (180 °C) LDT voxel conforming fully to a 20 µm high SU-8 mesa. (g) Confocal micrograph of a 10 µm × 70 µm voxel connecting two Au electrodes separated by a 20 µm high SU-8 mesa with (h) measured
I–V
plot. (j) SEM image of a 3D freestanding interconnect crossover made by LDT of a microbridge and pillars on a glass substrate. Panel (i) is the EDX spectrum of (j) showing Ag diffusion into the Au pad after oven curing at 250 °C. Panel (k) is the measured
I–V
plot of the interconnect in (j).
Figure 10.7 (a) Optical and SEM (insets) images of SRRs printed by LDT on silicon;
P
= 100 µm,
L
= 48 µm,
g
= 8 µm,
w
= 6 µm, and 0.7 µm thickness. Measured THz transmission spectra of Ag SRRs made by LDT (closed circle) and Au SRRs made by photolithography (open square) for (b) perpendicular (
E
⊥
) and (c) parallel (
E
‖
) electric field polarizations to the SRR gap. The simulated transmission spectra (solid line) are shown for both polarizations. SEM images of (d) double-square SRRs and (e) D-ring meta-antenna designed for an RF to optical modulator.
Figure 10.8 (a) Schematic diagram of an LDT multilayered stack. The FRL is a 2 µm thick Ag nanopaste layer spin-coated with a 1.8 µm thick photoresist layer. SEM image of (b) a cross section of a transferred multilayer stack (cured at 200 °C) on Si, part of which is exposed by focused ion beam (FIB) milling. SEM image (c) of Ag/polymer stacks with various planar areas transferred onto silicon. (d) Capacitance versus area/dielectric thickness for a Ag/photoresist (1818) stack.
Figure 10.9 Comparison of laser transfers of low-viscosity Ag ink and high-viscosity Ag nanopaste on Si. SEM images of laser transfers of (a) nanoink and (d) nanopaste with a square laser beam profile (insets). AFM height profiles of laser transfers of (b) nanoink and (e) nanopaste with a rectangular beam profile. SEM images of a grid, laser printed with multiple voxels of (c) nanoink and with a single (gridded) voxel of (f) nanopaste.
Figure 10.10 (a) Minimum laser transfer fluence versus 1/
D
(voxel diameter) for three different donor layer thicknesses. (b) Minimum laser transfer fluence versus donor layer thickness for three different voxel diameters. Error bars correspond to uncertainties in the measurement of the donor layer thickness and laser fluence. Lines are visual guides only. (c) Still frame images of a Ag nanopaste voxel released from the donor layer during LDT (with no receiving substrate). The red line in the first frame shows the location and size of the laser pulse (∼475 µm diameter). Time delay (
t
D
) is measured from the start of the laser trigger. The laser transfer fluence was 52 mJ/cm
2
, and the velocity of the voxel was calculated to be 0.9 m/s.
Chapter 11: Laser Printing of Nanoparticles
Figure 11.1 Laser printing of gold nanoparticles. (a) Photograph of a milk droplet in a coffee cup. (www.digifo-hka.de.) (b) SEM image of a gold surface subsequent to laser pulse irradiation.
Figure 11.2 Schematic illustration of femtosecond laser printing of nanoparticles in forward direction (LIFT).
Figure 11.3 Schematic illustration of femtosecond laser printing of nanoparticles in backward direction (LIBT).
Figure 11.4 SEM images of the laser printing process of different materials. The four images on the left side show the donor material surface subsequent to single-pulse laser irradiation. From left to right, the laser pulse energy is increased. The fourth image shows the donor substrate after the successful nanoparticle transfer. On the right side, transferred nanoparticles on the receiver substrate are displayed.
Figure 11.5 Laser-printed silicon nanoparticles on a glass substrate. For the printing process, 800 nm (a,b) and 400 nm (c,d) laser wavelengths have been used. The dark-field microscopic images reveal the different light scattering of the printed nanoparticles (a,c). The influence of the laser wavelength on the nanoparticle diameter can be seen in the SEM images (b,d).
Figure 11.6 Size distribution of silicon nanoparticles that have been printed by two different laser wavelengths from a silicon wafer.
Figure 11.7 Schematic illustration of femtosecond laser printing of nanoparticles using Gaussian (a) and ring-shaped (c) intensity distribution on the target surface. Resulting nanoparticles on the receiver substrate are shown on the right side (b,d).
Figure 11.8 SEM images of the donor (a) and the receiver (b) substrate (Germanium) subsequent to laser printing using ring-shaped intensity profile.
Figure 11.9 (a) Schematic illustration of femtosecond laser printing of nanoparticles. A silicon-on-insulator (SOI) wafer was used as a target to transfer spherical Si nanoparticles from 50 nm crystalline Si layer onto the transparent glass receiver substrate. (b) Array of several hundreds of amorphous Si nanoparticles (diameter of 160 nm) fabricated by this method and visualized with dark-field microscopy. The inset shows a SEM image of a single Si nanoparticle in this array.
Figure 11.10 (a) SEM images of nanoparticles fabricated at slightly different laser pulse energies starting from 5 nJ. Each line, from top to bottom, corresponds to the laser pulse energy increase of 0.1 nJ. (b) Changes in the optical response of the generated nanoparticles are visualized by dark-field microscopic images. The given nanoparticle diameters represent an average value with a deviation of ±5 nm.
Figure 11.11 Experimentally measured scattering spectrum of a single silicon nanoparticle.
Figure 11.12 Schematic representation of laser printing from prestructured gold substrate; (a) SEM images of nanoparticle structures before (b) and after (c) laser printing. Due to the surface tension, the shape of the nanoparticles is changing from flat triangular prism type to spherical.
Figure 11.13 SEM images of gold island structures that have been transferred into a silicone polydimethylsiloxane (PDMS). (a) Array of holes within a photoresist covered by a thin layer of gold (50 nm). (b) After a lift-off process, circular material islands with a diameter of 300 nm remain on the substrate. (c) The gold islands have been laser printed into a silicone polydimethylsiloxane (PDMS). The transfer results in spherical nanoparticles partially embedded into the polymer substrate.
Figure 11.14 (a) Schematic illustration of an ultraflat lens based on spherical gold nanoparticles. (b) Boundary conditions for the design calculations.
Figure 11.15 SEM images of the multistage process for the generation of an ultraflat lens based on spherical gold nanoparticles. (a) Array of holes within a photoresist covered by a thin layer of gold (50 nm). (b) After a lift-off process, circular material islands with a diameter of 300 nm remain on the substrate. (c) The gold islands have been laser printed into a silicone polydimethylsiloxane (PDMS). The transfer results in spherical nanoparticles partially embedded into the polymer substrate
Figure 11.16 Focusing effect of an ultraflat lens based on spherical gold nanoparticles. Intensity pattern obtained by calculations based on Mie theory (a) compared to experimentally measured intensity pattern (b).
Figure 11.17 Three-dimensional structure consisting of several thousands of silicon nanoparticles generated by laser printing.
Chapter 12: Laser Printing of Electronic Materials
Figure 12.1 Schematic representation of the four configurations of a thin-film transistor structure.
Figure 12.2 Typical output (a) and transfer (b) characteristics of a top contact OTFT.
Figure 12.3 Optical microscope image of a LIFT-printed OTFT. The substrate is a doped silicon wafer (gate) covered by a thin SiO
2
layer (dielectric) on which are printed (a) CuPc SC pixels (blue–green) and Ag-NP ink lines (white) as S/D electrodes or (b) diPhAc-3T pixels, printed by LIFT, and gold electrodes evaporated with
L
= 80 µm.
Figure 12.4 Schematic representation of the three OTFT configurations used to investigate the effects of laser printing of the dielectric layer on the OFTF characteristics. (a) BG-OTFT1: Si (gate)/SiO
2
(dielectric)/CuPc (SC)/Au (S/D); (b) BG-OTFT2: Si (gate)/SiO
2
+ PMMA (dielectric)/CuPc (SC)/Au (S/D); (c) TG-OTFT3 CuPc (SC)/Au (S/D)/PMMA (dielectric)/Al (gate).
Figure 12.5 Schematic representation of the single-step LIFT process used in the fabrication of multilayer structure for OTFT applications.
Figure 12.6 Structures of the receiver (a) and the donor (b) substrates.
Figure 12.7 A scheme of the red–green–blue PFO pixel transfer. The left image shows the transfer of the third, blue, pixel after the other two colors have already been transferred. The right image shows the receiver substrate alone with a bias across the three pixels creating electroluminescence.
Figure 12.8 Tricolor pixels imaged using a light microscope are shown for an Al/TBA cathode at 20 V (a) and for an Al cathode at 24 V (b). Electroluminescence (EL) spectra of tricolor LIFT pixels with an Al/TBA cathode (c) and with an Al cathode (d). On both graphs, the EL spectra of the “conventionally fabricated devices” are shown with a solid line and a color corresponding to the relevant device, and the printed pixels are represented with dotted lines and circles of corresponding color.
Figure 12.9 LIFT of a continuous line of silver inks in a single step at high velocity. The silver ink (Sun chemical U5714) has a viscosity of 11 mPa s and contains 40% of silver nanoparticle in weight. The UV picosecond laser operates at 1 MHz and scans the donor film at velocity of 17 m/s. (a) Schematic illustration of the setup. (b) Shadowgraphy images showing the formation of a large gas bubble in the donor film and the transfer dynamics of the continuous line toward the receiver substrate. (c) Optical microscopic image of the printed line showing a very uniform width of 25 µm.
Figure 12.10 Interdigitized electrodes LIFT-printed from silver nanoparticle inks with a UV picosecond laser operating at 1MHz and a scanner system to move the laser over the donor substrate. (a) Line width of 25 µm and distance between lines of 100 µm, (b) line width of 100 µm and distance between lines of 80 µm.
Chapter 13: Laser Printing of Chemical and Biological Sensors
Figure 13.1 Scanning electron microscopy (SEM) picture of the printed features of lambda phage DNA on glass substrate by laser-induced forward transfer (LIFT) using 500 fs.
Figure 13.2 Scanning laser confocal fluorescence microscopy of the Alexa 594 labeled lambda phage DNA pattern.
Figure 13.3 Wetting variation in relation to the laser printing energy that leads to the direct immobilization of the biomaterial on the screen-printed electrodes.
Figure 13.4 Optical microscopy image of microarray (IgG solution) at different laser pulse energies.
Figure 13.5 Optical microscope image of the micromembrane array following modification with the biological material.
Figure 13.6 Heavy metal ion detection using the capacitive sensor. (a) Sensors that were first spotted with the catalytic strand and then allowed to hybridize with their complementary substrate strand (red) increase their capacitance upon the insertion of heavy metal, contrary to the sensors with only the catalytic strands immobilized on their surface (blue). (b) After cleavage in the presence of heavy metal, all the sensing elements decrease their capacitance.
Figure 13.7 SEM analysis of the Au working electrode printed with thylakoid droplets, using (a) pipette and (b) laser-induced forward transfer (LIFT).
Figure 13.8 Capacitive sensor arrays. (a) Al contacts on the membranes. (b) Sensitive polymers (PVP-, PHEMA-, PAA-, and PVA-) printed in sensor device using LIFT.
Figure 13.9 TEM images of PVP/f-MWCNT and PAA/f-MWCNT composite layers through LIFT.
Chapter 14: Laser Printing of Proteins and Biomaterials
Figure 14.1 (a) Optical microscopy image of a DNA microarray printed by LIFT on glass. Laser fluence increases from bottom to top of the image: each laser fluence (1, 1.5, 2, 2.5, 3 mJ/cm
2
) is applied to deposit two rows of droplets. (b) Agarose gel electrophoresis (1) 3 mJ/cm
2
, (2) 4 mJ/cm
2
, (3) 5 mJ/cm
2
laser fluence, and (4) DNA control 12 ng/µl [51].
Figure 14.2 Strategy implying the direct and indirect labeling by fluorescence microscopy assays for the functional biotin patterns obtained by LIFT in a perfusion chamber. (a) The perfusion chamber was built from cleaned Corning cover glass and the patterned cover glass separated by a double-side tape spacer (red). (b) The direct labeling was based on one-step antibody–biotin coupling. (c) The indirect labeling was based on the fluorescent marked Atto-565-Streptavidin–biotin coupling. After incubation with the fluorescence labeling solution, all the samples were rinsed with PBS and distilled water. Fluorescence was detected using a Zeiss fluorescence microscope equipped with a Laser Scanning System Radiance 2100 (400–700 nm) and with a Carl Zeiss Axio Camera HR, and the signal intensity was quantified.
Figure 14.3 (a) Pattern diagram for obtaining spots onto different surfaces, that is, hydrophilic/hydrophobic. (b) 10 µm spot spacing on hydrophilic surfaces (glass). (c) 200 µm or more on hydrophobic surfaces (Ormocer). The spots were captured immediately after printing, the spot diameter and their spacing on the substrate were measured.
Figure 14.4 From left to right (a–c) without SDS, (d–f) with SDS. (a) and (d) Fluorescence microscopy images of photobiotin spots immobilized onto an Ormocer slide. (b) and (e) Cross-sectional profiles of the images (a) and (d), respectively. (c) and (f) Profiles of the surfaces shown in (a) and (d).
Figure 14.5 HRP transfer at a laser fluence of 260 mJ/cm
2
.
Figure 14.6 Peptide micropatterns transferred by LIFT and stained using Thioflavin T diagnostic tests. Scale bar is 50 µm.
Figure 14.7 Scanning electron microscopy image of part of (a) a printed peptide array and (b) one peptide droplet transferred by LIFT on a gold surface when the samples is left to dry in air, at room temperature after deposition. The presence of flat and elongated aggregates, 2–6 µm long and 0.2–0.5 µm thick peptide tapes can be noticed.
Figure 14.8 Optical microscopy images of SAW sensors printed by LIFT, by overlapping individual droplets at different center-to-center distances (ratio of overlapped length between two neighboring droplets to the individual droplet diameter (a) 30% overlap, (b) 50% overlap. (c) Comparison between sensitivities to octanol and carvone detection of the wtbOBP-, dmbOBP-, and wtpOBP-based biosensors. (d) Biplot of loadings and scores using the first two components of the principal component analysis.
Figure 14.9 Phase-contrast microscopy image (a) and fluorescence microscopy image (b) of giant liposomes in solution.
Figure 14.10 Fluorescence image of a microarray of liposome solution obtined at different laser fluences.
Figure 14.11 Raman spectra of the liposome solution after transfer at different laser fluences.
Chapter 15: Laser-Assisted Bioprinting of Cells for Tissue Engineering
Figure 15.1 Schematic representation of the different biofabrication approaches.
Figure 15.2 Patterning of different cell types by laser-assisted bioprinting with a range of cell concentrations. Observation of printed patterns of (a) mouse D1 mesenchymal stromal cell line, (b) human umbilical vein endothelial cells, (c) human progenitor endothelial cells, in phase-contrast microscopy, and (d) tdTomato-labeled human endothelial cells in fluorescence microscopy.
Figure 15.3 Coculture of human stem cells from the apical papilla (SCAPs) and tdTomato-labeled human endothelial cells created by laser-assisted Bioprinting. Observation of vascular-like network formation on day 6 (a) in phase-contrast microscopy and (b) in fluorescence microscopy.
Figure 15.4 Fluorescence microscopy images of human endothelial cell printed patterns, for future
in vivo
application in bone calvaria defect in mice. Observation of three relevant patterns of tdTomato-labeled endothelial cells on days 1 and 3 (D1 and D3, respectively) after laser-assisted bioprinting.
Figure 15.5 (a) Schematic representation of laser-assisted bioprinting setup; (b) Observation of TdTomato-positive mouse mesenchymal stromal cells (D1 cell line) patterns printed by LAB, in phase-contrast and fluorescence microscopy.
Figure 15.6
Top
: Schematic representation of the laser printing setup and the layer-by-layer approach. Laser printing technology allows for printing a grid structure (top view) of fibroblasts (green) and keratinocytes (red).
Bottom
: A seven-layer construct of red and green keratinocytes was obtained by laser printing (left; detail right). Scale bars are 500 µm.
Figure 15.7 Vascularization of tissue-engineering scaffolds. Schematic representation of the different strategies used for the formation and maturation of vessels in tissue-engineered constructs.
Figure 15.8 Creation of an organized multilayered construct of vascular-like network by laser-assisted bioprinting. observation of patterns of tdTomato-labeled endothelial cells in fluorescence microscopy (a) postprinting, (b) at D3; (c,d) observation of multilayered construct with patterns of tdTomato-labeled endothelial cells in fluorescence microscopy.
Figure 15.9 (a) Schematic representation of laser bioprinting setup. (b) Observation of printed patterns of human MSC and HUVEC on cardiac patch 24 h after bioprinting, (c) Patch implantation
in vivo
in a rat infarction model.
Figure 15.10 Illustration of the five major approaches used to support perfusion in bone constructs [68].
Figure 15.11 Observation of printed B35 neuronal cells in confocal microscopy, with the presence of axonal extensions between neuronal cells on different deposition planes.
Chapter 16: Industrial, Large-Area, and High-Throughput LIFT/LIBT Digital Printing
Figure 16.1 Scheme of Lasersonic® LIFT printing of black (absorptive) ink.
Figure 16.2 Lasersonic® LIBT printing of transparent inks.
Figure 16.3 Printing unit for continuous R2R printing of color pigmented NIR-transparent inks; the ink roller is precoated with a laser-absorbing material.
Figure 16.4 Optical laser beam path of the printing unit (one-color).
Figure 16.5 (a) Laser power signal of first diffracted order at 20 MHz (AOM input signal is displayed at screen bottom), (b) frequency response of the dynamical range for on/off.
Figure 16.6 Schematic diagram of
direct switching between power levels
. The RF input signal is switched each 20 ns according to the image data. The resulting laser pulses in the first diffracted order after the AOM need a rise time of 20 ns and a fall time of 20 ns (simplified shown as triangles with dashed lines). At the falling edge of these laser pulses, the next data pixel is already set and the next RF field has been started to propagate through the laser beam and already contributes to the effective laser power in the first diffracted order. The power curves of all pulses (dashed lines) are summed up to the effective laser power in the first diffracted order (bold curve).
Figure 16.7 Purpose of anamorphic optics: (a) scan direction with far field at polygon surface, (b) cross-scan direction with near field at polygon surface, insensitive against pyramidal error; if the polygon facet is slightly tilted, the beam follows the dashed line, but the focus point stays stable at the scanline.
Figure 16.8 Two-color double-printing unit for transparent inks. The laser beam alternates between left and right scanline.
Figure 16.9 Four-color Lasersonic® printing machine with unwinder and rewinder unit of the substrate, ink mixing and supply tanks, printing units, and human interfaces. The inking modules on top can be exchanged within a few minutes to vary between different inks or ink sequences.
Figure 16.10 Print unit for absorbing ink, the scanline is covered over the whole length by the donor ribbon, the laser comes from the backside, hits the ribbon under 60°, and is scanned along the scanline.
Figure 16.11 Printing unit for transparent inks lifted up for maintenance; in operation, the ink roller is positioned about 0.5 mm close to the substrate.
Figure 16.12 Roller inking unit for NIR-transparent inks.
Figure 16.13 Ribbon inking unit for NIR-absorptive inks.
