In a recent study published in Nature Communications, researchers introduced an innovative approach to improve the performance and stability of perovskite solar cells (PSCs) by using a tailored supramolecular interface.
This approach addresses key challenges in developing high-performance and stable PSCs, particularly the instability of the perovskite material at the interface with carrier transport layers.
Study: Stabilization of highly efficient perovskite solar cells with a tailored supramolecular interface. Image Credit: Kewiko/Shutterstock.com
Background
Perovskite materials have emerged as a promising option for next-generation photovoltaics (PVs) due to their excellent optoelectronic properties and compatibility with large-scale production methods.
These materials can be fabricated using low-cost and scalable techniques, making them an attractive alternative to traditional silicon solar cells. PSCs have made significant progress in power conversion efficiency (PCE), with certified values reaching 26.7% in single-junction devices, nearing the performance of crystalline silicon solar cells.
Additionally, compared to state-of-the-art silicon solar cells, PSCs offer a shorter energy payback time and lower greenhouse gas emissions over their lifecycle.
However, despite their great potential, the commercialization of PSCs has been limited by their inherent instability, especially at the interface between the perovskite layer and the carrier transport layers. This instability causes the device to degrade over time, affecting its long-term performance and reliability.
About the Research
In this study, the authors employed a supramolecular modulation strategy to fine-tune the interface properties of formamidinium-rich (FAPbI3-based) PSCs. This approach involves a two-step treatment process to passivate defects and improve the material's stability.
First, the perovskite layer is treated with a solution containing cesium (an alkali metal salt) and dibenzo-21-crown-7 (a crown ether). This treatment creates a gradient of cesium doping within the perovskite, effectively passivating defects and enhancing stability.
In the second step, the modified perovskite film is treated with an organic ammonium salt, such as phenylethylammonium iodide (PEAI), further improving interface properties by introducing a passivating layer that minimizes charge recombination and enhances overall device performance.
Furthermore, the researchers used various techniques to characterize the PSCs, including X-ray diffraction (XRD), scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) spectroscopy, atomic force microscopy (AFM), and Kelvin probe force microscopy (KPFM).
These methods provided a deeper understanding of the structural and electronic properties of the perovskite material and how they were influenced by the supramolecular interface engineering approach.
Key Findings
The outcomes demonstrated a significant improvement in the PV performance and operational stability of PSCs after implementing the supramolecular interface engineering strategy. The best-performing device achieved a certified PCE of 25.53%, one of the highest reported for FAPbI3-based PSCs.
Additionally, the unencapsulated device with dual host-guest (DHG) treatment retained approximately 96.6% of its initial efficiency after approximately 1,050 hours of continuous operation at room temperature, far outperforming the control and single host-guest (HG) treated devices.
The authors also observed a significant reduction in charge recombination and an improvement in overall charge transport properties.
These enhancements were attributed to the synergistic interactions between the passivating ammonium amphiphile and the crown ether at the crucial interface between the perovskite layer and the hole transport layer.
The supramolecular interface engineering led to a marked reduction in non-radiative recombination losses. This was evidenced by an 85-fold increase in photoluminescence quantum yield (PLQY) and a corresponding rise in quasi-Fermi level splitting (ΔEF) in DHG-treated devices compared to the control samples.
These improvements indicated a substantial decrease in defect-related recombination at the perovskite/hole transport layer interface and grain boundaries.
Additionally, AFM and KPFM revealed a significant reduction in surface roughness and a more uniform perovskite film distribution after DHG treatment, further contributing to better charge transport and reduced recombination losses.
Applications
This research has significant implications for advancing the performance and stability of perovskite-based optoelectronic devices, including solar cells, light-emitting diodes (LEDs), and sensors.
The supramolecular modulation strategy offers a promising method to enhance the efficiency and stability of PSCs, paving the way for their widespread adoption in renewable energy applications.
Additionally, this approach can be applied to various perovskite compositions and extended to other devices, such as photodetectors, especially in environments requiring thermal stability, like concentrated PV systems or high-temperature conditions.
Conclusion
In summary, the novel supramolecular interface engineering approach proved effective in improving the performance and stability of FAPbI3-rich PSCs.
The synergistic interactions at the perovskite/hole transport layer interface resulted in exceptional PV performance and stability, marking a significant advancement toward the commercialization of PSCs.
This method can potentially revolutionize the development of efficient and stable PSCs, meeting the growing global demand for clean, renewable energy.
The authors also highlighted the potential of supramolecular chemistry to overcome key challenges in creating high-performance, stable perovskite-based optoelectronic devices, ultimately contributing to a more sustainable energy future.
Journal Reference
Zhao, C., Zhou, Z., Almalki, M. et al. (2024) Stabilization of highly efficient perovskite solar cells with a tailored supramolecular interface. Nat Commun 15, 7139. doi: 10.1038/s41467-024-51550-z. https://www.nature.com/articles/s41467-024-51550-z
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