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Developed by scientists in Canada, the 0.049 cm2 solar cell was manufactured in ambient air and with a reagent known as phenyltrimethylammonium chloride (PTACl). It achieved an open circuit voltage of 0.95 V, a short circuit current density of 23 mA cm-2, and a fill factor of 80%.
Researchers at the University of Victoria (Canada) have built a flexible perovskite solar cell based on a polyethylene terephthalate (PET) substrate in open-air manufacturing.
They explained that PET is cheaper than polyethylene naphthalate (PEN) commonly used in substrates for flexible solar cells, and that the latter nevertheless has the advantage of being more thermally stable during the production process. PET, on the other hand, has a maximum temperature tolerance of 100°C and can tolerate deposition procedures below this threshold.
For this reason, the research group chose a cell architecture with a PET substrate and indium tin oxide (ITO), an electron transport layer (ETL) based on tin oxide (SnO2), a perovskite absorber of methylammonium lead iodide (MAPbI3), a hole transport layer (HTL) of Spiro-OMeTAD and a gold (Au) metal contact.
They deposited the SnO2 layer by annealing at 100 °C, the Spiro-OMeTAD layer at 50 C, and the perovskite absorbent at 100 C using an acetate/chloride salts coating. “The acetate component of this ink turns into a gas during the perovskite deposition process, creating a local positive pressure and moving the dust away from the deposition zone,” they explained. “The deposition of perovskite from this ink does not require clean rooms or an inert atmosphere. The chloride component, on the other hand, improves the crystallization dynamics of the film.”
The group built a cell with an active area of ??0.049 cm2 and a reagent known as phenyltrimethylammonium chloride (PTACl). “By adding PTACl to the SnO2 colloidal solution, we observed that the size of the agglomerates doubled, indicating that the phase transfer agent effectively increased the particle-particle interaction in the colloidal solution,” he stated.
Tested under standard lighting conditions, the flexible perovskite device achieved a power conversion efficiency of 17.6%, an open circuit voltage of 0.95 V, a short circuit current density of 23 mA cm-2, and a 80% filling.
The scientists also built a 1 cm2 device with the same configuration that showed an efficiency of 12.7%, an open circuit voltage of 0.97 V, a short circuit current density of 21.7 mA cm-2 and a fill factor of 60.2%. They stated that the loss in fill factor compared to the smaller device is due to the increased resistance of the ITO substrate, which they claim can be further improved through better electrode design.
“The incorporation of the phase transfer catalyst, PTACl, into the SnO2 colloidal solution improved the particle-particle interaction, increasing the coverage of SnO2 and strengthening the binding to the perovskite layer,” they stressed, adding that future research should focus on replacing MAPbI3 with more stable perovskite materials.
The device was presented in the study “ Enhanced Particle-to-Particle Interaction of Tin Oxide Electron Transporter Layer for Scalable Flexible Perovskite Solar Cells ” ), published in RRL Sola r. |
