Photovoltaic: All-italian the most efficient "tandem" solar cell technology

An innovative “tandem” solar cell in perovskite and silicon with a record efficiency [1] of over 26% was developed by an all-Italian group comprising researchers from the ENEA Photovoltaic Technologies Laboratory, University of Rome “Tor Vergata ”(With the CHOSE center [2]), the IIT - Italian Institute of Technology (with Graphene Labs and its spin-off BeDimensional). The results of this research were published in the international journal Joule.

The developed cell is composed of two solar cells mechanically coupled one over the other in order to work in tandem. The perovskite-based front cell, suitably sized, converts the blue and green light of the solar spectrum well, letting the red and infrared solar light pass towards the rear cell made of silicon.

"The combination of the two materials maximizes the absorption of the sun rays and produces a high photo-voltage, equal to the sum of the voltages generated by the two individual cells, thus producing greater efficiency than a single solar cell",  Mario Tucci, head of the ENEA Photovoltaic Laboratory, pointed out.

Two key elements in the construction of the tandem cell were crucial in obtaining high efficiency: graphene improved performance in the perovskite cell, while heterojunction with amorphous films in the rear silicon cell made it possible to increase its voltage. So far, record efficiency of 26.3% has been achieved, but the goal is to exceed 30%.

Thanks to the technique developed in the tandem cell structure  by the Italian researchers, it is possible to maintain the advantages of the individual manufacturing techniques, combining the simplicity of making perovskite thin films by means of a "solution process", with heterojunction silicon cells manufacturing.

For more information please contact:

Mario Tucci, ENEA – Photovoltaic Technologies Laboratory, mario.tucci@enea.it

Link to the article "Mechanically Stacked, Two-Terminal Graphene-Based Perovskite/Silicon Tandem Solar Cell with Efficiency over 26%"

[1] The efficiency of a photovoltaic cell is defined as the ratio between the electrical power available at the terminals of the photovoltaic cell and the power of solar radiation that hits the surface of the photovoltaic cell itself.

[2] Centre for Hybrid and Organic Solar Energy