Earlier this year, researchers from Brazil's UNICAMP and Italy's CHOSE (Centre for Hybrid and Organic Solar Energy) of the University of Rome “Tor Vergata” and the National Research Council of Italy (ISM-CNR) developed perovskite solar cells that exhibit excellent performance in transforming artificial light into electricity in indoor environments. These devices could provide clean and renewable energy for appliances used in homes, businesses, or industries, without the need for batteries.
In this work, the team developed an innovative surface treatment for the perovskite layer. “Under indoor lighting conditions (1000 lux, 500 lux, and 200 lux), our treatment substantially reduces interfacial trapping states, allowing for a performance of around 34% for low-bandgap perovskite modules. This performance is among the efficiency records reported in the literature,” says Francineide Lopes de Araújo, postdoctoral researcher at CINE and lead author of the work.
The treatment consists of depositing a mixture of the organic salt PEAI with the additive DIO onto the perovskite layer. As a result, a two-dimensional perovskite layer spontaneously forms over the three-dimensional perovskite, neutralizing its surface defects and improving its performance. The process takes place at room temperature; that is, the PEAI:DIO layer does not undergo any heat treatment after its deposition. “The PEAI:DIO mixture improves defect passivation, optimizes interfacial dipole alignment, and enhances charge transport; for this reason, it was possible to obtain high-performance devices,” specifies Francineide.
This strategy was employed in the fabrication of devices at different scales, from small-area solar cells to large-area modules, up to 121 cm2, formed by up to 15 subcells connected in series.
“The developed strategy demonstrates strong competitive potential in relation to other production methodologies for perovskite solar cells and modules, especially in terms of manufacturing simplicity and low cost impact,” says the postdoctoral researcher.
The results of this research reinforce the applicability of perovskite-based photovoltaic technology, enabling its use in low-power electronic devices used in indoor environments. “The technological advances achieved in this work contribute to making perovskite solar cells more viable for commercial-scale application,” concludes Francineide.
