Perovskite solar cells (PSCs) have emerged as a promising alternative to traditional silicon-based solar cells due to their low cost, high efficiency, and tunable optical properties. However, there have been challenges in achieving optimal performance in tin-lead (Sn-Pb) PSCs, particularly in attaining a near-ideal bandgap and a homogeneous component distribution within the perovskite film. Disordered heterojunctions caused by an inhomogeneous Sn/Pb ratio have been identified as a significant contributor to large recombination losses in these PSCs.
What causes disordered heterojunctions in Sn-Pb perovskite solar cells?
The disordered heterojunctions in Sn-Pb perovskite solar cells are primarily a result of inconsistencies in the Sn/Pb ratio within the binary perovskite film. This heterogeneity leads to variations in the local bandgap and causes defects and trap states, leading to increased recombination losses and reduced device performance. The challenge lies in finding a method to regulate the component distribution within the perovskite film to achieve a homogeneous structure.
How does introducing hydrazine sulfate help in achieving homogeneous component and energy distribution?
In a recent breakthrough, researchers at an esteemed institution successfully tackled the challenge of component distribution regulation in Sn-Pb perovskite solar cells through selective molecular interaction. Their findings, published in the Advanced Materials journal, highlight the role of hydrazine sulfate (HS) in achieving a homogeneous component and energy distribution within the perovskite film.
The addition of HS to the Sn perovskite precursor enables the formation of a hydrogen bond network in the perovskite film. This network coordinates with FASnI3, reducing the bond with Pb2+ and effectively regulating the crystallization rate of tin perovskite. This regulated crystallization brings the Sn-Pb perovskite film to the same level as its lead analog, thereby eliminating the disordered heterojunctions that cause large recombination losses.
“Our findings suggest that by introducing hydrazine sulfate, we can achieve a highly desirable homogeneous distribution of components within the Sn-Pb perovskite film,” said Dr. Wenxiao Zhang, one of the lead researchers involved in the study. “This breakthrough opens up new possibilities for significantly improving the efficiency and stability of Sn-Pb perovskite solar cells.”
What improvements are observed in Sn-Pb PSCs with HS?
The introduction of hydrazine sulfate (HS) in Sn-Pb perovskite solar cells brings about remarkable improvements in their performance. The Sn-Pb PSCs with HS exhibit significantly enhanced open-circuit voltage (VOC) and overall efficiency.
Specifically, the Sn-Pb PSCs with HS achieved an impressive VOC of 0.91 V, which is crucial for maximizing the power output of the solar cells. This is a substantial improvement compared to the previous state-of-the-art Sn-Pb PSCs, which struggled to achieve near-ideal VOC values.
Moreover, the efficiency of the Sn-Pb PSCs with HS soared to 23.17%, surpassing the performance of pure lead PSCs. This breakthrough demonstrates that the selective molecular interaction facilitated by HS can effectively address the challenges associated with heterojunction disorders.
Additionally, the research team discovered that the hydrogen bond interaction network and the strong bonding between Sn2+ and sulfate ions also contribute to improving the thermal, storage, and air stability of the resulting devices. This increased stability is crucial for the commercial viability of Sn-Pb perovskite solar cells as it ensures their long-term performance and reliability under diverse operating conditions.
Towards a New Era of Sn-Pb Perovskite Solar Cells
The exciting research conducted by Wenxiao Zhang and the team has shed light on the challenges associated with disordered heterojunctions in Sn-Pb perovskite solar cells. By introducing hydrazine sulfate (HS) into the fabrication process, they have successfully achieved a homogeneous component and energy distribution within the perovskite film, overcoming the limitations of previous approaches.
This breakthrough not only improves the performance of Sn-Pb PSCs, with significantly enhanced VOC and overall efficiency, but it also enhances the stability of these devices. These findings open up new possibilities for the widespread adoption of Sn-Pb perovskite solar cells, offering a low-cost and highly efficient alternative to conventional silicon-based solar cells.
As solar energy continues to gain prominence in our quest for sustainable and clean energy sources, the advancements in Sn-Pb perovskite solar cells marked by this research bring us one step closer to a future powered by the sun.
Original research article: Component Distribution Regulation in Sn-Pb Perovskite Solar Cells through Selective Molecular Interaction
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