Researchers from The Hebrew University of Jerusalem in Israel have reported the fabrication of flexible and semitransparent perovskite-based solar cells.
Much of the research in the field of building-integrated photovoltaics is focused on semitransparent perovskite solar cells on glass substrates, which can be utilized as glass windows during the construction of the buildings. In their recent study, the team chose to develop cells that can be used in existing windows through a retrofitting process.
The transparency of the cells is obtained through printing transparent and noncolored “optical holes” at micrometric dimensions.
The fabrication approach is based on inkjet printing pillars composed of polymerized N-vinylcaprolactam, followed by inkjet printing of a perovskite layer, to attain a digitally tuned semitransparency, all performed in open air.
The printing compositions are tailored, including the solvents with a controlled volatility, adding a surfactant to fit both the inkjet printing process and the vacuum-assisted perovskite crystallization.
The flexible semitransparent solar cells achieved a power conversion efficiency (PCE) of 9.14%, with an average transmittance of 29.3%. Beyond transparency, the pillars also contributed to the mechanical properties: bending measurements reveal that the device without the pillars retains 71.4% of the PCE after 300 cycles compared to the pillared device which retains 90% of its initial PCE after 500 bendings.