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Chinese researchers have developed a new chemical bath deposition technique to deposit tin oxide on the flexible substrate of a perovskite cell without the need for a strong acid. The resulting cell has achieved a certified efficiency of 24.90% and remarkable stability.
Researchers at Chinas Tsinghua University have developed a flexible perovskite solar cell based on a tin oxide (SnO2) electron transport layer (ETL). The novelty of the proposed cell design consists of the chemical bath deposition (CBD) method used to deposit the SnO2 on the flexible substrate.
“This CBD method differs from previous research by using tin sulfate (SnSO4) instead of tin(II) chloride (SnCl2) as the tin precursor to deposit SnO2, making the new method compatible with sensitive flexible substrates. to acids,” explains the lead author of the research, Chenyi Yi. “The residual SO42- sulfate remaining after SnSO4-based CBD also benefits the stability of the perovskite solar cell due to the strong coordination between the lead (Pb2+) of the perovskite and the SO42- of the SnO2.”
The research group explained that the quality of the ETL is key to achieving high power conversion efficiencies in flexible perovskite solar cells and noted that SnO2 was chosen due to its high mass charge mobility, wide bandgap and good band alignment. of energy with perovskite. However, they also added that uncontrolled growth of nanocrystals during the CBD process can lead to a narrow deposition window for high-quality SnO2 film, which in turn can lead to “unsatisfactory” reproducibility.
The academics built the cell with an indium tin oxide (ITO) and polyethylene terephthalate (PET) substrate, the SnO2 ETL, a perovskite adsorbent, a spiro-OMeTAD-based hole transport layer (HTL), and a gold (Au) metal contact.
Tested under standard lighting conditions, the device achieved a power conversion efficiency of 25.09%, an open circuit voltage of 1.188 V, a short circuit current density of 25.29 mA cm-2, and a fill factor of 83.5%. The researchers also specified that the cells efficiency was certified at 24.90% by an unspecified testing entity.
They also claimed that the device was capable of retaining 90% of the initial efficiency after 10,000 bending cycles. “The controllable growth of SnO2 not only ensures excellent reproducibility of CBD, but also allows reuse of the chemical bath, which shows great promise for large-scale applications,” the group explained.
“The ultimate goal is for these high-efficiency flexible perovskite solar cells to move from laboratory scale to industrial production, allowing widespread commercial application of this technology in various fields, from wearable technology, wearable electronics and from aerospace power sources to large-scale renewable energy solutions,” Yi added.
The new cell design was presented in the study “ 25% – Efficiency flexible perovskite solar cells via controllable growth of SnO2,” published in iEnergy . |
