Photovoltaic RFID tags: thanks to MIT the IoT is even smarter

RFID technology (Radio-Frequency Identification) plays a fundamental role in the most disparate fields, acting as a fruitful alternative to barcodes and magnetic stripe cards. The advantages of use are many, including the ability to read - multiple and simultaneously - the tags without targets, the constant updating of the data tracked by the management system and the excellent degree of flexibility of the devices which are highly customisable, as well as non-duplicable.

Among the many worthy aspects that characterize this technology, the need for electrical power can be seen as a limit. It is precisely to cross this limit that the researchers of Massachusetts Institute of Technology (MIT) have designed a type of RFID tag powered by light, thanks to the use of perovskite photovoltaic cells.

THE MIT SOLUTION

At present, IoT sensors - and therefore RFID tags - require batteries that must be replaced or recharged periodically, a factor that can be problematic for the monitoring long-term. RFID tags with photovoltaic systems, on the other hand, could transmit data for years before needing to be maintained or replaced.

The project involves thin film photovoltaic cells made in perovskite – grafted onto active radio frequency identification tags – which are extremely flexible, transparent, easy to manufacture and efficient in terms of powering the tag itself.

To crown the value of this technology, the cells are able to power the sensors both in conditions of intense sunlight and in situations characterized by artificial light, in closed environments. The perovskite used – as confirmed by Ian Mathews, one of the authors of the study – can in fact be optimized to collect energy from any type of internal and external lighting, thanks to its “incredible indoor light absorption potential”.

Furthermore, the research team found that the RFID tags created in this way are able to cover greater data transmission distances and that they allow the possibility of integrating multiple sensors on a single tag, thanks to the increase in power provided by solar energy .

PHOTOVOLTAIC RFID: A LOW-COST TECHNOLOGY

The advantages of RFID devices made with perovskite cells include various areas. First of all the environmental one, which sees this technology stem the consumption - and therefore the disposal - of batteries, limiting the pollution produced with their use. And if on a functional level the improvements are guaranteed - with, in fact, greater coverage and power - on the production side there is also a significant economic saving.

As is known, RFID technology itself is one low-cost technology. A characteristic in common with perovskite, an economical, high-productivity material, which has proven to be able to efficiently convert large quantities of the solar energy it receives into electricity.

In recent years, the performance of perovskite in solar cells has attracted the attention of researchers and manufacturers, becoming the protagonists of studies and experiments. Distancing itself - therefore - from traditional solar cells, which are more cumbersome and expensive to manufacture, and largely surpassing other thin film solar cell technologies studied for decades.

The particular combination between RFID and perovskite technology, therefore, could count on a good diffusion and availability of the components - all at very low costs - which would make it usable with ease and in a short time on a large scale.

Large-scale production also allows the costs of the manufacturing process to be easily absorbed testing of radio equipment which also applies to these devices.

THE VALUE OF AN AMBIENT LIGHT IOT

Given that RFID (Radio-Frequency Identification) technology confirms its leading position among IoT resources in areas such as access control, logistics, security and so on, a technological innovation such as active photovoltaic tags could revolutionize consumption – and performance – of numerous cases and sectors.

It goes without saying that - to better understand the scope and value of this solution - the discussion can be broadened to all Internet of Things devices. In the next five years, in fact, experts estimate that the number of IoT devices could reach i 75 billion all over the world.

Devices which, in the current state of affairs, would involve a proportional use - as well as maintenance, recharging and disposal - of batteries, defining an IoT that is anything but sustainable.

For this reason, various battery-free IoT devices and networks have been studied and tested by numerous research teams. Two of the more frequent limitations among these solutions are the stochastic collection of energy and its accumulation in small capacities; factors that force us to rethink the paradigm of IoT devices as continuously functioning.

To date, with the experimentation of perovskite solar cell IoT devices, these problems seem to have been contained or, at least, satisfactorily contained. To bring this experimental technology to fruition and make it have a significant impact on the IoT - underline the MIT authors - a substantial commitment is expected in the development of RFID circuits with detection functionality, as well as the lead removal from perovskite cells, in a key to full environmental sustainability.

For the certification of radio equipment, even in cases where the opportunities of new technologies and innovative solutions are exploited, it is essential to be supported by expert figures in the sector such as Sicom Testing right from the preliminary stages.