Researchers at the Nankai University in China have fabricated a perovskite solar cell using a 2D/3D perovskite heterointerface that improves device stability and performance.
The interface is placed between the perovskite and the hole transport layer, which improves charge-carrier transport/extraction while suppressing ion migration. Cells with this architecture usually exhibit large exciton binding energies and are generally more stable than conventional 3D devices due to the protection provided by the organic ligands.
The research team explained that it used an argon plasma polishing pre-treatment (APP) to remove the surface defects from the perovskite layer and increase passivation effectiveness.
“We found that APP can effectively remove impurities adsorbed on the surface of thin films, eliminate perovskite soft lattices and enhance the extraction and transport of charge carriers,” it highlighted. “Furthermore, APP can adjust the surface composition of perovskite, which is beneficial for subsequent low dimensional perovskite passivation and reduces non-radiative recombination of charge carriers.”
Several perovskite films were annealed at 120 C for 15 min in air with 25 % relative humidity and were then treated with or without APP. APP was found to increase lead presence on the surface of the perovskite film and a decrease in the proportion of iodine. “This indicates that argon plasma reconstructs the surface interface of the perovskite, removing some iodine while leaving the lead on the surface,” the academics stressed.
Image: Nankai University, Next Materials, CC BY 4.0
The scientists built the cell with a substrate made of glass and fluorine-doped tin oxide (FTO), a hole transport layer (HTL) relying on tin oxide (SnO2), the perovskite absorber, the 2D interface layer, an electron transport layer (ETL) based on Spiro-OMeTAD, and a gold (Au) metal contact. Its performance was compared to that of a reference cell built without the APP treatment.
Tested under standard illumination conditions, the APP-treated cell achieved a power conversion efficiency of 23.53 %, an open-circuit voltage of 1.18 V, a short-circuit current density of 24.45 mA/cm², and a fill factor of 81.5%. The control device, by contrast, reached an efficiency of around 22%.
“The performance improvement is mainly attributed to the increase in open-circuit voltage, indicating a better passivation effect by exposing the solid perovskite sub-surface for 2D transformation and effectively suppressing non-radiative recombination,” the researchers explained. “A slight increase in short-circuit current suggests improved carrier extraction and transport at the perovskite interface.”
Furthermore, the APP-treated cell was found to retain over 80 % of its initial efficiency by the fourth week, while the benchmark device saw its efficiency drop “rapidly” to 73%. “The improved stability indicates that further 2D passivation, achieved by removing the perovskite soft lattice, contributes to better heterointerface properties,” they concluded.
The new cell concept was presented in the study “Enhancing 2D/3D heterointerface via argon plasma polishing for efficient perovskite solar cells,” published in Next Materials.
This content is protected by copyright and may not be reused. If you want to cooperate with us and would like to reuse some of our content, please contact: editors@pv-magazine.com.
By submitting this form you agree to pv magazine using your data for the purposes of publishing your comment.
Your personal data will only be disclosed or otherwise transmitted to third parties for the purposes of spam filtering or if this is necessary for technical maintenance of the website. Any other transfer to third parties will not take place unless this is justified on the basis of applicable data protection regulations or if pv magazine is legally obliged to do so.
You may revoke this consent at any time with effect for the future, in which case your personal data will be deleted immediately. Otherwise, your data will be deleted if pv magazine has processed your request or the purpose of data storage is fulfilled.
Further information on data privacy can be found in our Data Protection Policy.