How To Design Conductive Inks For Printed Electronics
XTPL is a leading innovator in the field of microtechnology and conductive inks.
They specialize in developing advanced materials that play a crucial role in modern electronics. Conductive inks are essential in creating flexible and efficient electronic circuits. These inks are used in various applications, including printed electronics, sensors, and displays. Their importance lies in their ability to conduct electricity while being applied in thin, flexible layers, enabling the creation of advanced electronic devices.
Conductive inks are the cutting edge in electronics production and XTPL has developed a range of them, each tailored to the specific applications and requirements of their customers.
These inks, which can be extruded in multiple ways, including three-dimensional layering – a layer of ink extruded onto another – and laterally to create a slightly more substantial trace. Each ink has special properties useful in certain applications.
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Different Types of Conductive Inks Developed by XTPL
Silver Conductive Ink
Silver conductive ink is known for its excellent conductivity and reliability. This ink is widely used in printed electronics, photovoltaic cells, and RFID tags. Its properties include low resistance and high stability, making it ideal for applications requiring precise and efficient electrical performance.
Flexible Conductive Ink
We designed flexible conductive ink to maintain conductivity even when applied to bendable or stretchable surfaces. This ink is crucial for the development of flexible electronics, including wearable devices, flexible displays, and soft robotics. Its ability to adhere to various surfaces without losing conductivity makes it a versatile solution for advanced electronic applications.
The Role of Conductive Inks in 3D Printing
XTPL has integrated conductive inks into the realm of 3D printing, enabling the creation of complex, three-dimensional electronic circuits. These inks allow for the precise dispensing of conductive materials onto various substrates, facilitating the production of customized electronic components. The use of 3D printer conductive ink by XTPL is the key to producing lightweight and compact electronic devices with intricate designs that traditional manufacturing methods cannot achieve.
Conductive inks have significantly advanced the capabilities of 3D printing. With XTPL’s innovations, it is now possible to print conductive traces directly onto 3D-printed objects, streamlining the production process and reducing the need for assembly. This advancement opens up new possibilities for creating smart objects and embedded electronics, enhancing the functionality and integration of electronic components in various devices. The combination of 3D printing and conductive inks paves the way for rapid prototyping and the development of next-generation electronics.
Further, these traces can wind throughout a printed object, essentially embedding the electronics inside a monobloc product. This innovation allows for the creation of uniquely rugged products unimaginable even a few years ago.
Applications of XTPL’s Customizable Conductive Inks
XTPL’s conductive inks are extensively used in printed electronics, where they enable the fabrication of flexible and lightweight electronic circuits. These inks are used in producing thin-film transistors, sensors, and other electronic components that require precise and reliable conductivity. The ability to print electronics on various substrates expands the potential applications and improves the efficiency of electronic device production.
Printed Circuit Boards (PCBs) are fundamental components in most electronic devices. XTPL’s conductive inks are used to create the intricate pathways that connect different components on a PCB. These inks ensure high conductivity and durability, essential for the reliable performance of electronic devices. The customization offered by XTPL allows for the creation of PCBs with specific properties tailored to various applications, enhancing the functionality and performance of the end products.
Conductive inks from XTPL also have potential applications in electroplating. They can be used to create conductive patterns that serve as the base for electroplating processes, enabling the dispensing of metal layers onto non-metallic surfaces. This capability is valuable in various industries, including automotive, aerospace, and consumer electronics, where electroplating is used to enhance the properties of components such as durability, corrosion resistance, and aesthetic appeal.
XTPL’s customizable conductive inks offer versatile solutions for a wide range of applications, driving innovation and efficiency in the electronics industry.
Silver printed microdots
The Science Behind the Silver Ink’s High Conductivity
XTPL’s silver ink is especially valuable to product engineers simply because it works so well. We chose silver as a base material for conductive inks primarily due to its excellent electrical conductivity. Among all metals, silver has the highest electrical and thermal conductivity, which makes it an ideal candidate for applications requiring efficient current flow. Its ability to maintain conductivity even when reduced to nanoscale particles ensures that silver-based inks can be used in a variety of high-performance electronic applications.
Silver’s atomic structure allows electrons to move freely, reducing resistance and facilitating the smooth transmission of electrical signals. This property is crucial for applications that demand precise and reliable conductivity. Additionally, silver nanoparticles can be dispersed in a solution to create ink that can be applied to various substrates, forming highly conductive paths. This enhances the overall performance of electronic devices by ensuring minimal energy loss and efficient signal transmission.
The Innovation Behind XTPL’s Conductive Ink Distribution System
XTPL’s conductive ink distribution system represents a significant innovation in the field of printed microelectronics. The concept began with the idea of making conductive ink application as simple as drawing with a pen. The design process involved creating an extruder that could dispense a precise amount of conductive ink, ensuring consistent and reliable conductivity. This required developing a special formulation of conductive ink that would flow smoothly and adhere well to different surfaces while ensuring that the extruder head did not smear the ink while being applied.
The system allows for precise and highly controlled extrusion of XTPL’s various inks and ensures nearly perfect nanotraces on nearly any surface. By engineering the extruder to be completely compatible with the inks themselves, we have ensured that producers can manage every part of the manufacturing chain.
Conclusion
We explored XTPL’s advancements in conductive ink technology. We discussed the various types of conductive inks developed by XTPL, including silver, carbon, clear, and flexible conductive inks. Each type offers unique properties and applications, contributing to the versatility and efficiency of modern electronics. We also examined the role of conductive inks in 3D printing, highlighting how they enhance the capabilities of this technology. Furthermore, we looked at the applications of XTPL’s customizable conductive inks in printed electronics, PCBs, and electroplating. The science behind the high conductivity of silver ink was explained, along with the innovative design and potential uses of XTPL’s conductive ink pen.
Looking ahead, XTPL’s customizable conductive inks hold great promise for the future of electronics. Continued innovation and development in this field could lead to even more efficient and versatile conductive inks, further expanding their applications. As technology evolves, the demand for flexible, lightweight, and high-performance electronic components will continue to grow, positioning XTPL’s conductive inks as key enablers of future advancements in electronics.
Printing books and newspapers can be seen as much easier to be manufactured than microelectronic components, but the difference becomes much narrower with time. Thanks to technological developments, it’s possible to produce advanced microelectronic devices with relatively similar scale, simplicity, and speed as when printing a New York Times bestseller or a popular newspaper.
The inks used in printed electronics are to some extent similar to the ones used for graphics printing, but they have a much greater impact on the final product. After all, normal ink only has to look good and withstand the test of time without fading away. Ink for printed electronics has to conduct electricity and be durable in a way that enables devices and systems to work properly and efficiently on end.
How do you go from printing newspapers to printing electronics? Let’s find out!
Step 1: To make conductive ink, you need special components
To become conductive, ink needs to be enriched with conductive components. For this purpose, in addition to the basic ink constituents such as solvents and additives, a variety of organic and inorganic materials must also be applied, such as:
- Metal nanoparticles,
- Carbon nanomaterials,
- Conductive polymers,
- Quantum dots.
These components, readily or later on, introduce electric charges which can move freely within the material. This ease of electron flow conducts electricity through the printed structures. Different “recipes” of employing these components can result in various additional properties of the final product and impact its end-use performance.
Choosing conductive materials and other ingredients is the first step of designing a conductive ink. Once we understand what type of ink will be best for our specific use case, next we need to take into account other vital aspects to successfully deposit high quality conductive paths that our electronics demand.
Step 2: Understanding the relationship between ink and printed technology
Choosing materials is one thing, but you need to know exactly what happens to your ink when you start printing it and during operation. Essentially, you’re adding nanomaterial ingredients to your ink, and you have to do it in just the right way to make a specific technology work.
For successful printing, it’s necessary to understand:
- the physicochemical parameters of your ink and any material in it,
- the substrate surface that you’ll be printing on,
- the requirements of the tech you’re printing.
Moving on, each printing method demands different ink properties, so your ink characteristics should be carefully tuned to the requirements of the chosen printing technique.
Next, the ink formulation has to be compatible with the surface on which it’s printed, with precisely engineered wettability and adhesion.
Lastly, you need to adjust the process parameters and sintering conditions, or you might also need to prepare the substrate surface in a special way.
To put the puzzle together and enable efficient printing, all these aspects should be considered when optimizing your ink formulation.
Step 3: Processability and printability of conductive inks
Conductive ink must be processable and printable to make the printing process work. Achieving this comes down to optimizing multiple characteristics of the conductive ink, including:
- Size of functional particles,
- Ink rheology,
- Evaporation rate,
- Surface wetting.
Ink rheology
Rheology describes how a fluid responds to applied force. During printing and when it’s in operation, an ink goes through different types of stress which influence its properties.
The two key rheology aspects in this case are viscosity and surface tension.
Viscosity
This tells us about the resistance of a fluid to flow, which is related to the internal friction of a moving fluid. When temperature goes up, viscosity goes down. Each printing technique requires a specific range of ink viscosity. Ultimately, optimizing viscosity comes down to a compromise between ink processability, printing resolution, and precision. Too low viscosity, and the ink might cause overspraying. Too high, and your ink may clog the printing nozzle or be hardly printable.
At the moment, printing tech is more powerful than ever and high-performance conductive features are in large demand, so higher ink viscosity is usually preferred. Plus, ink with high viscosity leaves a more solid print after the solvent evaporates, and it’s less sensitive to surface properties of a used substrate.
Surface tension
This is the effect of cohesive forces of liquid molecules. These forces push together molecules on the surface of a liquid, minimizing the occupied area. A liquid with a low surface tension spreads over a substrate surface more than a liquid with a higher surface tension.
Generally, higher surface tension of the ink is beneficial because it results in higher printing resolution and fewer satellite droplets outside of the desired printing area. If the print pattern has to stick and stay on the product, the surface tension of the ink has to be lower than the surface energy of the substrate.
Evaporation rate
Ink that dries quickly can be good for shorter production times, but it can also clog printing nozzles, which is a fundamental problem that’s best avoided. If the ink dries out too quickly or too slowly, the printed material might end up unevenly distributed—in other words, it might have non-uniform morphology.
What’s important, a non-uniform morphology of printed features might cause bad performance of the end device.
Surface wetting
This is another big factor that influences the morphology of the printed film, the adhesion to the substrate surface, and the printing resolution.
For the ink to behave properly, the wetting conditions need to be optimized—meaning that the surface tension of the ink must match the surface energy of the substrate. This is what makes the lines consistent, and determines minimum line width, as well as resolution between adjacent lines.
Result: High-quality printed conductive patterns
The key steps to design a conductive ink that meets your needs are:
- Selecting conductive materials,
- Understanding the relationship between ink properties, chosen printing method, and final electronics performance,
- Optimizing key characteristics for processability and printability.
Proper ink design plays a huge role in printing high-quality conductive patterns. Optimizing ink for a specific use case (and specific printing technology) leads to efficient performance in the end product.
Thank you for reading this article! If you’re interested in nanoprinting for microelectronics, here’s what you can do next:
- Check out technical papers about our nanoprinting technology,
- Contact us and tell us about your printing needs.
Written by:
Daria Więcławska, Business Development Specialist at XTPL
Ludovic Schneider, R&D Manager at XTPL
References:
S. M. F. Cruz, L. A. Rocha, and J. C. Viana, “Printing Technologies on Flexible Substrates for Printed Electronics,” Flex. Electron., 2018.
M. Zenou and L. Grainger, Additive manufacturing of metallic materials. Elsevier Inc., 2018.
C. Cano-Raya, Z. Z. Denchev, S. F. Cruz, and J. C. Viana, “Chemistry of solid metal-based inks and pastes for printed electronics – A review,” Appl. Mater. Today, vol. 15, pp. 416–430, 2019.
K. Kwon, K. Rahman, T. H. Phung, S. D. Hoath, and S. Jeong, “Review of digital printing technologies for electronic materials,” Flex. Print. Electron., vol. 5, no. 043003, 2020.