Science News: 2022 Energy Environ. Sci. (IF 38.532), Perovskite Solar Cells with High Fill Factor over 86%! By Regulating Deep-level defects and Charge Extraction
In recent years, the power conversion of perovskite solar cell (PSC) has received great attention due to its rapid development. However, the reported fill factors (FFs) still lag behind those of commercialized solar cells, and a comprehensive understanding of the mechanism is lacking. Researchers published a study in Energy Environ. Sci. in 2022. Here, the authors adopted a simple and effective strategy to increase the FF to 96.3% of the Shockley-Queisser (S-Q) limit through homogeneous incorporation of CsPbBr3 crystals (Note: The S-Q limit is the theoretical energy conversion limit that a solar cell can achieve by using a single PN junction, and it is also one of the most basic principles of using photovoltaic cells to produce solar energy.), which can greatly passivate deep-level hole defects and thus lead to dramatically enhanced hole mobility to balance with electron mobility.
The results of the study showed that:
1. With the improvement of carrier extraction efficiency, non-radiative recombination is suppressed, resulting in a significant PCE of 25.09% (certified: 24.66%) and a record FF of 86.9%, which is the highest FF reported for PSCs so far.
2. In-depth analysis shows that the strategy can simultaneously reduce FF loss caused by series resistance, shunt resistance and non-radiative compounding.
This work provides an effective strategy to promote FF close to the theoretical limit.
Device statistics for a. VOC, b. JSC, and c. FF and d. PCE for the devices with different amounts of CsPbBr3.
Comparison of FF and PCE of devices obtained in this work with those reported in literatures with PCE exceeding 24.5%. Note that FF values reported in these literatures are all smaller than 85%.
Top surface SEM images and statistic distribution of grain sizes of FAPbI3 without and with pre-crystallized CsPbBr3 and PbBr2/CsBr powder, respectively.
Key Word: Perovskite solar cell, fill factor, Shockley-Queisser limit, hole defect
Article link: https://doi.org/10.1039/D2EE02543D