| Work Detail |
European scientists have used a nanosecond pulsed ultraviolet laser to reduce surface defects in perovskite films intended for solar cell applications.
A European research team has tried to improve the performance and efficiency of a perovskite solar cell by passivating surface defects in the perovskite film using a commercial laser treatment.
“Our work is a proof of concept, and we are constantly working on advanced results,” co-corresponding author Monika Rai told pv magazine , noting that the proposed approach is solvent-free and industrially scalable.
They used an industrial nanosecond pulsed ultraviolet (UV) laser at two different energy intensities of 160 nJ and 650 nJ, respectively.
They then used scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements to assess the effect of the laser pulse on film morphology and found that both intensities resulted in a uniform grain size distribution and clear grain boundaries, although the highest intensity also showed some weathered perovskite grains.
In contrast, the lower intensity laser pulse did not damage the perovskite surface or affect its properties. “There are no observable differences in the binding energy or broadening of the spectra at low laser energy, suggesting a negligible change in the chemical properties of the perovskite surface,” the researchers say. "At high laser energy, the overall absorption decreases due to obvious destruction in the film, as corroborated by XRD and SEM measurements."
The team applied the treatment to a solar cell based on the triple cesium methylammonium formamidinium cation (CsMAFA) and found that its efficiency increased from 18.0% to 19.3%, also improving stability performance. “At power optimized, laser-polished devices show improved open-circuit voltage (VoC) and fill factor, due to reduced recombination losses at the interface, unlocking the high-Voc potential of similar bandgap perovskites,” they noted, adding that the cell achieved a remarkable Voc of 1.21 V.
The cell was able to maintain around 90% of its initial efficiency for 1,000 h, compared to 75% for a reference device to which no laser treatment was applied.
“This technique may be particularly suitable for roll-to-roll (R2R) production lines,” Micahel Saliba, co-author of the study, told pv magazine .
Details of the method, laser power adjustment, and measurement methods are documented in “ Light Makes Right: Laser Polishing for Surface Modification of Perovskite Solar Cells. ” perovskite solar cells), published in ACS Energy Letters . The research group is made up of scientists from the University of Stuttgart and the Brandenburg University of Technology Cottbus-Senftenberg (Germany), the University of Luxembourg and the University of Valencia (Spain). |
