Chinese researchers have used Mortise-Tenon technology to combine a perovskite absorber with a hole transport layer in a perovskite solar cell. They say this reduces non-radiative recombination while improving the cell’s open-circuit voltage and fill factor.
MT structures are commonly used in woodworking for strong joints between different materials that provide resistance to twisting. In the proposed configuration, the MT structure consists of a perovskite absorber and a thermally polymerized additive called N-vinyl-2-pyrrolidone (NVP) used for the hole transport layer (HTL).
According to the researchers, NVP maintains a strong interaction with perovskite precursors during the spin-coating process, resulting in improved charge transport and high-quality perovskite/NVP films.
The cell structure includes a glass/fluorine-doped tin oxide (FTO) substrate, a SnO2-based HTM, a perovskite absorber with NVP, a spiro-OMeTAD layer, and a gold (Au) metal contact.
Comparing the performance of the device with the reference cell, the master device had a power conversion efficiency of 24.55%, an open circuit voltage of 1.187 V, a short circuit current density of 25.66 mA cm−2 and a duty cycle of 80.64%. . The researchers highlighted the advantages of suppressed non-radiative recombination and balanced interfacial charge separation due to the high-quality perovskite crystals and Mortise-Tenon structure.
In contrast, the reference device achieved an efficiency of 22.91%, an open-circuit voltage of 1.151 V, a short-circuit current density of 25.21 mA cm−2 and a duty cycle of 78.94%.
In addition, the cell with the MT structure showed excellent durability, retaining more than 95% of its original efficiency for 1100 hours. The device has been measured and certified at the Quality Testing Center for Solar and Wind Power Systems of the Chinese Academy of Sciences.
They presented the cell technology, “Monolithically-granulated perovskite solar cell with Mortise-Tenon structure for charge-depletion balance,” published recently Nature communication.
“Our work highlights the role of increasing the contact area of the perovskite layer and HTL and suggests a unique strategy to realize interfacial charge-removal balance in perovskite solar cells, which may be an important approach to achieve an efficient device in the future,” they concluded. .