Screen Printed Electrode Fabrication and Uses

Jump to: Why Use A Screen Printed Electrode? | Commercially Produced SPEs | Screen Printing Electrodes
Requirements for Screen Printed Electrode | Applications of SPEs

The screen-printed electrode (SPE) is an important development within electrochemical analysis methods, offering a sensitive, cheap, and simple platform for sensing technologies across various fields. Screen printed electrodes can be particularly useful for environmental analysis sensors, detecting biomolecules and biomarkers, flexible electronics and more.

While commercially produced SPEs are available for quick, reliable testing and established assays, the ability to screen-print electrodes in-house provides significant advantages for research, including lower costs, flexibility in materials and geometry, and the development of novel applications like wearable, flexible electronics.

Why Use A Screen Printed Electrode?

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Electrochemical techniques are widely used in sensor technology to measure analyte concentration in solution. This methods are valued for these applications as they are sensitive, cheap and relatively easy to execute.

Electrochemistry methods often require a working, reference and counter electrodes. Traditionally, these electrodes are suspended within an electrochemical cell, that is filled with the electrolyte. This system is connected to a potentiostat, which takes electrochemical measurements such as cyclic voltammetry. Since these measurements depend strongly on electrolyte properties and the surfaces of the electrodes, they can  detect the slightest changes in the system, and easily track reactions over time.

Due to its simplicity, this method can be scaled down for use micro-analytics and microfluidics experiments. The development of microelectronic technology means that masses of information can be analyzed quickly. Therefore, data needs to be collected and processed more rapidly than ever. This has led to the development of small, 2D devices capable of conducting electrochemical and microfluidics experiments on a chip.

A screen printed electrode plays an important role in these 2D devices. With screen printing and clever device design, all the electrodes (working electrode, reference electrode & counter electrode) can be deposited in a single plane. This simplifies their production, making it possible to create specific single-use sensors for a range of applications.

Commercially Produced SPEs

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The ease of production and widespread application of this technology has led to the mass production of screen-printed electrode (SPEs). These SPEs are produced with a specific architecture, the surface properties of which can be modified to be used for specific experiments.

Commercialized SPEs are a benchmark for many experiments with well-established protocols, such as in-vitro diagnostics and quantification of cancer markers. Using commercial SPEs helps ensure repeatability and consistency between tests.

However, there are limitations to commercial screen-printed electrodes, which may drive users to produce their own “home-made” or “in-house” screen printed electrodes.

Why Screen-Print Your Own Electrode?

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Many applications need custom designs or have specific requirements that can't be met by commercially produced electrodes. Exciting new materials, novel applications and more complex demands for miniaturized systems is constantly driving innovation in this field. In these cases, researchers may seek to screen print their own electrodes. 

In-house printed electrodes have the following advantages compared to their commercial alternatives:

• Cheaper

  Especially in the research stage. Commercially produced SPEs cost at least several dollars per unit. Once researchers invest in the necessary screen-printing equipment, the cost of producing each electrode is significantly lower. This cost saving is especially important if you are experimenting with device architecture or new materials. Any investment in commercial SPEs could be wasted if they are incompatible with your device.

• Producing Custom Geometries

  In-house screen-printing technology allows for maximum flexibility in material selection, modifications and device architecture. Screen printing your own electrodes is beneficial if you are optimizing new processes, materials, substrates, or ideas.

• Flexible Applications

  Flexible electronics have many potential applications such as medical patches used for more comfortable monitoring, flexible displays or wearable electronics. Standard SPEs are generally produced on glass, and while you can get commercial flexible SPEs, they are more expensive than their rigid alternatives. Plus, they might not use biocompatible materials.

• Novel Ink Development

  Any process or device with specific ink requirements may require specific electrode properties. For example, Room Temperature Ionic Liquids don’t interact well with commercially printed electrodes, even dissolving them in some places. You may therefore wish to optimize the material of your electrode to match the properties of your coating ink. You will not be able to do this using commercially produced electrodes.

Requirements for Screen Printed Electrode

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To reliably screen print custom electrodes, it is important to ensure a consistent process. Also, any innovative screen-printed electrodes must outperform commercial SPEs in some way, be this in novel ink properties, cheaper manufacturing or using eco-friendly materials.

One of the benefits of screen printing is that it’s relatively simple to master. When depositing an electrode, film thickness is not that important. This makes screen printing electrodes even more straight forward.

It's a good idea to use a dedicated screen printer to ensure reliable and repeatable deposition. In terms of parameters to optimize, you should consider:

• Printing speed
• Applied printing pressure
• Pattern Spacing
• Printing gap

You will also need to optimize your solution to ensure suitable adhesion, wettability, sufficient flow and viscosity, as well as ensuring good electrical properties.

Applications of Screen Printed Electrodes

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Gold, silver and platinum are commonly used electrode materials in electrochemistry. For thin films, these materials are often deposited using evaporation techniques. However, gold nanoparticles suspended in solution can be screen printed. Additionally, silver-based inks are perfect for screen printing.

Some of the most interesting alternative electrode materials are carbon or graphene-based materials. Graphene and carbon nanotubes have great potential for electrodes as they have incredible charge carrying behaviour.

Screen printed electrodes can facilitate drop analysis, conducting tests using extremely small amounts of solution. Microfluidics testing cards using screen printed electrodes can facilitate the real time analysis of pollutants in field.

More recently researchers have experimented with creating sensors on various materials such as paper. Paper-based microfluidic analytical devices, that can easily facilitate microfluidic channels, are biodegradable and could be extremely useful for single use sensor or tests.

Custom-printed electrodes have been recently used to monitor sweat during exercise. Screen printing electrochemical sensors which can differentiate between lactate, glucose + potassium ions have been shown to be useful to differentiate between anaerobic and aerobic states. Further work demonstrated scalable, paper-based printed electronic devices which can detect sodium, ammonium and lactate in sweat.

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