Azure Photon develops perovskite solar cells to replace disposable batteries

The world appears to be becoming ever more reliant on disposable batteries. “In 2025 alone, 78 million batteries will have been thrown away every day, with a significant economic and environmental impact,” says Azure Photon, a new spin-off from the Faculty of Engineering of the University of Porto. It is proposing a clean, “long-life” alternative designed to last for more than a decade.

Official projections indicate that, by 2030, more than 40 billion IoT (Internet of Things) devices will be in operation. Although many of these products have an expected lifespan of close to 10 years, their batteries need replacing every two years on average, creating “a growing mountain of electronic waste”. The affected equipment includes small devices such as temperature, humidity, motion and air-quality sensors, smart labels, meters, monitoring systems and countless products that continuously collect and transmit data, as well as wireless keyboards.

With this challenge in mind, Azure Photon was created with the aim of replacing conventional batteries with perovskite solar cells able to harvest energy from indoor lighting and power smart devices throughout their entire working life.

A crystal developed in the laboratory

The technology created by Seyedali Emami and Jorge Martins, researchers at LEPABE - the Laboratory for Process Engineering, Environment, Biotechnology and Energy - together with Adélio Mendes, a full professor in FEUP’s Department of Chemical and Biological Engineering, uses perovskite solar cells. Perovskite is a crystal found in nature but can also be manufactured in a laboratory with light-absorbing properties.

“It is an emerging photovoltaic technology made from abundant, low-cost materials, and it stands out for its exceptional ability to generate electricity even in low-light conditions. In indoor settings, these cells have already achieved a record energy-conversion efficiency of 44.7%, far surpassing traditional silicon and thin-film solar technologies,” the researchers explain.

In practical terms, they say, the technology “can turn artificial light in offices, warehouses, shops and smart homes into a clean, continuous energy source that is sufficient to power IoT sensors and devices without requiring ongoing maintenance”. This is made possible through a laser-based hermetic sealing process that shields the photovoltaic cells from moisture and oxygen, two of the main causes of degradation. It also relies on a process developed at FEUP that operates at temperatures below 100°C, whereas conventional methods require more than 400°C - levels that are incompatible with the sensitive materials used in perovskites.

2,500 hours of stability

According to the company, cells encapsulated using this method have already shown more than 2,500 hours of stability in accelerated tests under solar illumination, a result regarded as “essential to the project’s commercial viability”.

The next phase is to launch the first device, providing an energy alternative that can cut electronic waste, lower operating costs and increase the independence of the smart devices underpinning the digitalisation of buildings, industry and infrastructure, “in line with European carbon-neutrality targets and the United Nations Sustainable Development Goals”, they say.

The batteries, which Azure Photon says are considerably more sustainable than current options, “can be easily adapted to existing sensors”, Jorge Martins notes. He acknowledges that potential customers span several sectors, including industry, construction, supermarkets and freight-transport logistics. However, he adds: “It is still very difficult to compete with traditional batteries on cost. We are talking about a very early-stage technology competing against the mass production of disposable batteries.”

Two projects under way

“At present, disposable batteries cost between 50 cents and €1, while our solution costs €3, even at scale with a minimum production run of one million batteries,” the researcher says. He is confident that the company’s manufacturing could become competitive within five years, “depending on funding and the market”.

For now, Azure Photon has two projects under way. One, under the StartUP Voucher Innovate 2025–2026 programme, is worth €30,000 and has been used to develop three prototypes of electronic devices powered by solar cells, as well as market studies. The other, under Norte 2030, has €900,000 in funding to produce solar cells and prototypes and to carry out field validation in real buildings.

“What we need to do now is move from the laboratory to commercialisation,” says the researcher of a project born from a doctoral thesis. It is beginning to attract interest from potential international customers, particularly in construction and retail, where a supermarket may have more than 7 million electronic labels, each powered by a battery.