Breaking New Ground: Achieving Record Voltage with Transparent Perovskite Solar Cells

A team of researchers from the University of Stuttgart in Germany has made a groundbreaking advancement in the field of perovskite solar cells. They have successfully developed a single-junction transparent perovskite solar cell with an impressive voltage of 1.78 V, setting a new record in the industry.

The key component of this cell is a hybrid methylamine lead chloride (MAPbCl3) perovskite material, known for its high energy bandgap among all perovskites. This unique material opens up exciting possibilities for wide bandgap perovskite solar cells, both in applications like Internet-of-Things (IoT) and solar windows, as well as in multijunction solar cells.

Until now, single junction perovskites with wide bandgaps have struggled to achieve high voltages. The limitation lies in the fast crystallization kinetics and poor solubility of the material's precursors. This results in incomplete film coverage and an irregular film morphology.

To overcome this limitation, the research team employed a two-step deposition method followed by annealing under molecular nitrogen (N2) gas within a glovebox. By controlling the annealing atmosphere, they were able to influence the crystallization kinetics of MAPbCl3 without affecting its bulk properties. This process significantly improved surface coverage and film uniformity.

The construction of the solar cell involved several layers, including a fluorine-doped tin oxide (FTO) substrate, an electron transport layer (ETL) based on carbon-titanium dioxide (C/TiO2), a TiO2 mesoporous layer, the MAPbCl3 absorber, a Spiro-OMeTAD hole-transporting layer (HTL), and a gold (Au) metal contact.

Under standard illumination conditions, the cell exhibited impressive performance metrics. It achieved a power conversion efficiency of 0.81%, an open-circuit voltage of 1.71 V, a short-circuit current density of 0.73 mA cm−2, and a fill factor of 64.7%.

Notably, the cell demonstrated an extraordinarily high open-circuit voltage of 1.78 V, which is the highest ever recorded for a perovskite solar cell based on MAPbCl3. It is worth mentioning that this voltage was achieved using the conventional spiro-OMeTAD hole-transporting layer, optimized for narrow bandgaps. This surprising result indicates that the same contacts used for world-record efficiency perovskite solar cells with narrow bandgaps can sustain such high voltages.

The researchers published their findings in a recent paper titled "MAPbCl3 Light Absorber for Highest Voltage Perovskite Solar Cells," available in ACS Publications.

This groundbreaking achievement paves the way for further advancements in high-voltage perovskite solar cells, bringing us closer to more efficient and sustainable energy solutions. With the potential for wider applications and improved performance, the future of perovskite solar cells looks brighter than ever.