Research

Researchers develop low-cost and efficient solar cells from a new class of semiconductor materials

Paola Vivo
Paola Vivo was recently nominated as Tenure Track Professor at Materials science and environmental engineering unit. She leads Hybrid Solar Cells -group of researchers.
Researchers at Tampere University are developing nanotechnology-based photovoltaic devices that can be fabricated on a variety of surfaces. According to Associate Professor Paola Vivo, flexible and affordable perovskite solar cells can even be integrated into textiles and building façades.

Paola Vivo leads the Hybrid Solar Cells (HSC) group in the Faculty of Engineering and Natural Sciences at Tampere University. The team is working to identify and develop increasingly efficient and more environmentally friendly materials and solutions for harnessing solar energy, such as hybrid solar cells made up of organic and inorganic materials.

Silicon is still the main component of conventional solar cells. Paola Vivo believes in the enormous potential of halide perovskite, a cheaper alternative semiconductor to silicon. Vivo has explored the optoelectronic properties of perovskite materials and their utilization in solar cells during the last few years.

“Perovskite solar cells (PSCs) are the greatest breakthrough in solar cell technology since the 1970s.  Despite being discovered only a few years ago, PSCs have already reached efficiencies exceeding 25%, almost equal to those of silicon-based solar cells after many decades of research. PSCs are not only efficient but have also a low energy payback time, are lightweight, and can be printed on flexible substrates,” Vivo says.

Perovskite solar cells embedded into IoT sensors or building façades

Halide perovskite semiconductors display exciting optoelectronic properties for a wide range of applications. The great flexibility in tailoring their composition opens up numerous ways to process them while fine-tuning the optoelectronic properties. If made stable and nontoxic, PSCs could be used as a power source in small-scale portable electronics, such as smartwatches and IoT sensors, or they can even be woven into fabric. PSCs also have the potential to make visually unobtrusive building-integrated solar cells a reality.

“The transparency and color of perovskites can be tuned by chemically adjusting their structures, so PSCs could fulfil the visual comfort requirements of building façades yet still meeting the ever-growing energy demand” Vivo explains. 

Perovskite solar cells on glass substrate fabricated by HSC researchers.
Perovskite solar cells on glass substrate fabricated by HSC researchers. Photo: Arto Hiltunen / Tampere University

PSCs are not yet commercially available but may be brought to the market as early as 2021, according to the key companies involved in perovskite development.

A major drawback is that PSCs contain toxic lead. The HSC team has succeeded in designing a range of lead-free perovskite materials, with grain size down to the nanoscale, which are currently under testing. Recently, they proposed a new tin-germanium alloy that has been published in the prestigious Angewandte Chemie journal.

Building an international reputation for research excellence

Paola Vivo has recently taken up an associate professorship (tenure track) in materials science and environmental engineering at Tampere University. Vivo sees her new appointment as an opportunity to drive PSC research forward. 

“My associate professorship offers me the opportunity to expand my research team and our range of research equipment. My goal is to build a strong international reputation for the Hybrid Solar Cells team as a developer of sustainable, stable, and efficient photovoltaic solutions,” Vivo sums up her vision. 

In the future, Vivo is looking to focus on improving not only the efficiency of PSCs but also their mechanical stability. She finds it important to examine the mechanical stability of solar cell materials already at the design stage of photovoltaic solutions, though this aspect is often overlooked. 

“Mechanical stability tests can shed light on the types of surfaces into which the material can be integrated. To accelerate the discovery and optimisation of new solar cell materials, I am also keen to make increasing use of the latest computer-aided technologies alongside experimental research,” Paola Vivo adds.

Read more and meet the rest of the team on the website of the Hybrid Solar Cells group.

Further information

Paola Vivo
tel.
+358 44 340 7081
paola.vivo [at] tuni.fi

Text: Anna Aatinen
Photo of Paola Vivo: Jonne Renvall

What is perovskite?

Perovskite is a mineral containing calcium titanate (CaTiO3) that wasdiscovered in the Ural Mountains of Russia in 1839. The crystal structure of halide perovskite semiconductor is similar to that of the perovskite mineral. A perovskite solar cell includes a perovskite layer that captures sunlight. Metal halide perovskite is a material with extraordinary optoelectronic properties, such as strong photoluminescence and long charge diffusion length. Perovskite solar cells are efficient, lightweight, flexible and far cheaper to produce than silicon-based cells.

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