Green and beautiful: The benefits of embedding electronics in ceramic tiles
By Ronan Daly
Most buildings drawing on solar energy are clearly advertising their green credentials. Solar panels, whether on the sides or roofs of structures, are unmissable, and provide a look all their own.
But new research we’re undertaking at the Institute for Manufacturing, with partners at the Universitat Politècnica de València in Spain, shows how such power could get more subtle. Printed electronics embedded within ceramic tiles offer a new option to architects seeking to create buildings with a variety of looks while remaining environmentally minded.
A new idea with a firm foundation
The idea of having printed electronics on the outside of buildings is not new. But embedding them within ceramic tiles is, and we believe it offers two critical advantages.
The first is the lifetime of the electronic devices. Externally facing electronics, especially anything organic, degrade rapidly as they are exposed to the elements. By embedding electrical connections and devices within the ceramic tile, many of these parts could be protected, with those bits that are not embeddable being easily replaced by clipping on and off in distinct locations.
The second advantage is that this is a process that the ceramic tile industry is already primed to implement. In traditional producer countries like Spain and Italy, there has been an industry-wide move away from conventional screen printing of graphics with large runs to inkjet printing and print-on-demand. This has dramatically reduced waste, as well as storage and warehousing, and helped these manufacturers compete with new producers like China.
Printing electronics with inkjet printing is already widely used, notable for producing touchscreen displays. And though the ceramic tile industry has not yet adopted this, the components needed — the digital manufacturing systems, the expertise, the printers, the infrastructure — already exist in their operations.
At the IfM, we are developing a system that preserves the functionality of embedded electronics through the high-intensity process of compressing and firing ceramic tiles, and doing it in a way that can be adopted by industry.
Tiles are made from a ceramic powder that is compressed and heated to 1200°C, so creating electronics that can survive that can be a challenge. We do it by controlling the amount of oxygen present during the process, but whereas we can easily create a zero-oxygen environment in the lab, this is not practical for industrial uses. So, we are learning from industry about what low-oxygen environments they can create, and developing a method for our embedded electronics to survive.
We also are working on controlling the porosity of the ceramic, as space within the tile is needed in order to connect the different embedded components.
One method of embedding electronics uses a two-layer compression approach already widely used by the ceramic tile industry. Our twist is that in between the compression of layer one and two, we print the electronics onto the first layer, which is then covered with the second.
Because we can control the porosity, we are then able to print components such as interconnects onto the complete tile and allow the material to seep down from the surface and make contact with the embedded components, which are safely in between the two layers.
We’re now studying the details of porous flow and material sintering to understand how to control this process better.
When this process is refined, these tiles could be produced at scale — either by creating individual tiles that can take in energy and use it themselves, or through a system of multiple tiles that connect to each other and act as sources of energy within the building envelope.
Energy would be low-level, but it would be continuous, and would not affect the exterior look of the building. Patterns, graphics and visual elements prized by architects would still be possible, but with function embedded inside.
That energy could be used for a range of functions, including things like powering pollution sensors and other environmental monitoring. These can help us to understand our environmental impact better and are currently available, but are not a regular integration into new construction. Ceramic tiles with embedded components could encourage the wider adoption of these devices.
There are also areas where more efficient and powerful solar panels are simply not appropriate. Historic and conservation buildings, for instance, could now have an option to go greener while preserving their protected character.
These types of tiles would not approach the level of energy generation of conventional solar panels. But as another option in the effort to make construction greener, they are an exciting development — and an aesthetically pleasing one as well.
This work is an ongoing collaboration between researchers at the IfM (Dr Ronan Daly, Professor Abir Al-Tabbaa, Regana Vasanthanayagam, Dr Maria Cristina Rodriguez-Rivero) and Universitat Politècnica de València (Professor Javier Orozco-Messana, Ian Fausto Zanchetta Chittka). For more information on results to date, read our paper “Cu2O–ZnO heterojunction solar cell coupled to a Ni(OH)2-rGO-PPy supercapacitor within a porous stoneware” by Orozco-Messana et al., Ceramics International, Volume 46, Issue 16, November 2020, Pages 24831–24837.