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The Chinese Academy of Sciences has presented a high-efficiency perovskite solar cell, with a maximum efficiency of 26.1%, using 1-(phenylsulfonyl)pyrrole (PSP) as an additive. The cell is third-party certified with an efficiency of 25.2%, and maintains 92% of its original efficiency after 2,500 hours of operation.
The Chinese Academy of Sciences announced this week that its researchers have manufactured homogenized perovskite films that could increase the efficiency and stability of perovskite solar cells.
The scientists claim that they have solved the typical problem of phase segregation that inevitably occurs inside perovskite films and that affects both the power conversion efficiency and the thermal stability of perovskite photovoltaic devices. This is a problematic issue, since illumination, such as sunlight, alters the delicately ordered composition of elements within mixed halide perovskites.
“We all know from previous work that cations from different groups are distributed inhomogeneously, but it is still not clear how exactly they are distributed, why and how it affects the efficiency,” explains researcher Xu Pan. “We have visualized the inhomogeneity out-of-plane compositional along the vertical direction through the perovskite films and we have identified the underlying reasons and potential impacts for the devices.”
The researchers state in “ Out-of-plane cations homogenize perovskite composition for solar cells ,” recently published in Nature , that they measured the vertical distribution of FA+ cations. and Cs+ in the movie. They discovered the aggregation of Cs+ at the bottom of the film and the concentration of FA+ at the top interface.
“Then we discovered that cations from different groups crystallize and transform at very different rates,” Pan said, referring to the main cause of the films inhomogeneity.
To create more homogeneous films, the group used an additive known as 1-(phenylsulfonyl)pyrrole (PSP), which they said successfully accomplished its mission.
Using the optimized perovskite film, the academics built a solar cell with an active area of ??1 cm2. Tested under standard lighting conditions, this device showed a power conversion efficiency of 26.14%, an open circuit voltage of 1.164 V, a short circuit current density of 26.14 mA/cm2, and a fill factor of 85.74%. The cell was also able to retain 92% of its original efficiency after 2,500 h.
The scientists also claimed that an undisclosed external entity has certified the cells efficiency at 25.2%. |
