In the ongoing quest to improve solar energy efficiency, scientists have made a significant breakthrough with inverted perovskite solar cells—a type of photovoltaic device that holds great promise for the future of renewable energy. Researchers from NingboTech University [29.8°N, 121.6°E] have developed a lead carbanion (carbon anion) complex (Pb–C–) to enhance both the efficiency and stability of perovskite solar cells. This new method allows the solar cells to convert more sunlight into electricity while reducing the surface defects that have previously hindered their performance.
The Breakthrough: Lead Carbanion as a Game-Changer
Perovskite solar cells have been hailed for their potential to surpass traditional silicon-based cells in efficiency and cost. However, they have long faced a major issue: energy loss at the interface between the perovskite layer (which absorbs sunlight) and the electron transport layer (which moves the electrical charges). This is due to defects at this interface that cause carrier recombination—a process where generated electrons lose energy instead of contributing to the electrical output.
The research team’s novel solution involves applying a lead carbanion passivator to the perovskite surface. The Pb–C− bond formed between the carbanion and the lead-rich perovskite surface significantly reduces the surface defects and mitigates the energy losses caused by nonradiative recombination. As a result, the solar cell achieves a power conversion efficiency (PCE) of 25.16%—an impressive figure for inverted perovskite cells, which are typically held back by lower efficiencies compared to their conventional counterparts.
Inverted Perovskite Solar Cells
To understand the significance of this innovation, it’s helpful to know how inverted perovskite solar cells differ from traditional designs. These cells have a structure referred to as “p-i-n”, where the hole-selective contact (p) sits at the bottom, followed by the intrinsic perovskite layer (i), with the electron transport layer (n) on top. This contrasts with conventional perovskite solar cells, which have the “n-i-p” configuration. Inverted cells are known for their excellent stability under various environmental conditions, but historically, they have lagged behind in efficiency.
By addressing the issue of energy loss at the interface, the lead carbanion complex helps to bridge this gap, providing the benefits of both efficiency and stability in one package.
Important Implications for Both Efficiency and Stability
One of the most remarkable outcomes of the study is the open-circuit voltage (Voc) of 1.17 V, which is the highest ever recorded for an inverted perovskite solar cell. This high voltage is a key factor in the cell’s overall performance, helping to reduce voltage loss to just 0.38 V—a minimal figure that ensures more of the sunlight captured is turned into usable energy.
Moreover, the stability of these solar cells is equally impressive. With a lifespan exceeding 600 hours in humid conditions, and the ability to retain 90% of their initial efficiency over three months without special encapsulation, these cells offer both high performance and durability.
Beyond Solar Power
The research team is not stopping at solar cells. The successful synthesis of lead carbanion passivators opens up new possibilities for further advancements, not only in photovoltaics but also in other areas of electronics and materials science. By exploring different cation combinations, they hope to create even more stable and efficient devices in the future, potentially expanding the use of this technology beyond solar energy.
This advancement in perovskite solar technology is significant: By reducing defects at the critical interface where energy losses occur, these solar cells achieve both world-class efficiency and remarkable stability. The application of lead carbanion passivation shows that even incremental innovations at the material level can lead to substantial improvements in performance, pushing the boundaries of what solar energy can achieve.
In a world striving for more sustainable energy solutions, innovations like these are key to ensuring that renewable energy sources can meet the demands of future generations, with perovskite solar cells now standing as a frontrunner in this green revolution.
Source
Lead carbanion anchoring for surface passivation to boost efficiency of inverted perovskite solar cells to over 25%, Chemical Engineering Journal, 2024-11-01
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