A team from the Institute of Materials Science of Seville (ICMS), a joint centre of the Spanish National Research Council (CSIC) and the University of Seville (US), has developed a new hybrid device that allows energy to be captured from both the sun and rain simultaneously. A thin film created and patented by the research team not only protects and improves the durability of perovskite solar cells, even in adverse weather conditions, but also allows nanogenerators to produce more than 100 volts from the impact of a single drop of water, enough to power small portable devices.
Halide perovskite solar cells are photovoltaic devices composed of synthetic materials with a crystalline structure and excellent sunlight absorption properties. Although silicon technology is the most widely used, perovskite technology has great potential to revolutionise photovoltaic energy due to its high efficiency and low cost. However, degradation or instability in environmental conditions is one of its major drawbacks. Faced with this challenge, the ICMS research team has used plasma technology to create and deposit a protective film of about 100 nanometres on the solar cells. On the one hand, this system acts as an encapsulant that chemically protects the perovskite cells and optically improves their ability to absorb light; and, on the other hand, it has a triboelectric surface (which generates electrical charge through friction or contact) that converts the kinetic energy of raindrops into electrical current.
The results show the new material's ability to generate up to 110 volts per impact from a single raindrop, enough to power a small portable device. In addition to scalable production using sustainable techniques, the coatings have demonstrated remarkable stability in extreme environments such as immersion in water, can continuously power simple electronic devices such as LED circuits, and enable solar panels to withstand environmental conditions associated with humidity-temperature stress cycles.
"Our work proposes an advanced solution that combines perovskite solar cell photovoltaic technology with triboelectric nanogenerators in a thin-film configuration, thus demonstrating the feasibility of implementing both energy harvesting systems," explains Carmen López, a researcher at ICMS.
Decline in batteries
Faced with the limitations of conventional batteries and the loss of efficiency of solar panels on cloudy days, this technological advance aims to propose an innovative solution based on the sun-rain symbiosis. Its purpose is to provide energy autonomy to portable and wireless electronic devices, allowing them to operate continuously in both sunny and rainy conditions.
The authors highlight that the development of the device represents a significant innovation for the entire Internet of Things (IoT) industry, including environmental sensors (humidity, rain, pollution), structural sensors (bridges, buildings), weather stations and precision agriculture.
"Its implementation in so-called smart cities is feasible, such as in signage, autonomous auxiliary lighting or monitoring, as it can withstand adverse weather conditions and the presence of rain, humidity and thermal cycles. It would also be applicable for distributed energy structures in remote, inaccessible or isolated areas, such as marine stations," says ICMS researcher Fernando Núñez.
The work provides a novel approach that opens up new avenues for developing autonomous and robust electronic systems for outdoor use. "Our research highlights the potential of coatings deposited by plasma techniques as a multifunctional solution that protects sensitive energy devices and develops systems capable of collecting energy from different environmental sources, such as hybrid solar-rain panels, known as rain panels," the researchers conclude.
The results were obtained thanks to the 3DScavenegrs project, funded by the European Research Council (ERC Starting Grant), and the Drop Ener project, co-funded by Next Generation funds, which have enabled progress in the development of triboelectric nanogenerators from raindrops protected by the Energy Harvesting Device patent.