22.6% Efficiency For Flexible Foldable Perovskite

International journal Cell Reports Physical Science has published a research work that claims to have achieved 22.6% of power conversion efficiency for flexible and foldable solar PV cells designed for indoor environments. It credits a collaboration between researchers from Italy’s Tor Vergata University of Rome, Germany’s Fraunhofer Institute for Organic Electronics, and Colombia’s South Colombian University for this project.

“We have optimized the perovskite photovoltaic cells on ultra-thin flexible glass, incorporating a mesoporous scaffold on compact layers of SnO2, which offer a leap forward in efficiency, reaching 20.6% (at a specific power of 16.7 μW/cm2), and 22.6% (with 35.0 μW/cm2) below LED lighting levels of 200 and 400 lux respectively,” said doctoral students of Electronic Engineering at CHOSE Sergio Castro-Hermosa and Giulia Lucarelli ‘Tor Vergata’ research team led by Prof. Thomas Brown.

For their research, the team deposited indium tin oxide (ITO) with a roll-to-roll method having transmission coefficiency of around 80%, ohmic resistance (13 Ω / square) and flexibility, overcoming bending procedures 1,600 times with 20.5 mm curvature.

The research work published is titled Perovskite Photovoltaics on Roll-To-Roll Coated Ultra-thin Glass as Flexible High-Efficiency Indoor Power Generators. The team used flexible perovskite PV cells manufactured on ultra-thin flexible glass substrates 100 μm thick and coated with ITO.

As per the team, the efficiencies obtained represent the highest reported for any flexible and folding PV cell technology for indoor use. These levels also exceed the previous perovskite cells on flexible substrates by 60% to 90%, they claim, while adding that the special powers in W delivered per gram of weight under indoor lamps are 40% to 55% higher than their counterpart on PET plastic films and are of an order of magnitude higher than those on rigid glass.

These cells are illuminated by an indoor lamp and supply energy to wireless sensors, low-consumption electronics for home use, smart homes and the internet of things (IoT).

“These figures highlight the great potential of integration of these ultra-thin and ultra-light devices in electronic components for interiors,” added Prof. Thomas Brown. “All the active layers of the perovskite photovoltaic cells have been deposited at low temperature and by deposition processes in liquid solution, which means that the roll-to-roll manufacture of devices on ultra-thin flexible glass can be implemented not only for the ITO layer, but in the future also for all the other layers by means of printing techniques.”

In February 2020, the Italian university and the country’s National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) claimed 26.3% efficiency for a silicon and perovskite tandem solar cell using graphene (see Italian Researchers Claim 26.3% Efficiency For Tandem PV Cell).