Lithium Doping Boosts Perovskite Solar Cell Lifespan, New Research Shows
Berlin, Germany – A novel approach to stabilizing perovskite solar cells-a promising option to traditional silicon-based photovoltaics-has emerged from research published this week in Angewandte Chemie International Edition. Scientists have demonstrated that incorporating lithium dopants into the spiro-OMeTAD hole-transporting layer significantly enhances the cells’ operational stability under realistic day-night cycling conditions, addressing a key hurdle to their widespread commercialization.
Perovskite solar cells offer the potential for high efficiency and low-cost production, but their susceptibility to degradation from environmental factors like moisture, oxygen, and light has limited their long-term performance. This new finding directly tackles a major degradation pathway: oxidation of the spiro-OMeTAD layer, a critical component for extracting and transporting positive charges within the cell. The research indicates that lithium doping effectively “paves the air-free oxidation” of spiro-OMeTAD, preserving its functionality and extending the lifespan of the device.
Researchers led by Yang, H. et al. found that lithium ions interact with oxygen vacancies within the spiro-OMeTAD,preventing the formation of detrimental oxidized species.This stabilization is notably crucial during the repeated heating and cooling cycles that mimic daily sunlight exposure and nighttime temperature drops. The team reported enhanced power conversion efficiencies and significantly improved stability compared to undoped control devices.Further advancements in hole-transporting materials are also contributing to perovskite cell improvements. Liu,X. et al. (2023) demonstrated that extending the π-conjugated system within spiro-type materials boosts both efficiency and stability. Similarly, Lai, Q. et al. (2023) showed that incorporating multifunctional liquid crystal additives into the hole transport layer can also enhance performance and longevity.These parallel efforts, combined with the lithium doping strategy, represent a multi-pronged approach to overcoming the remaining challenges in perovskite solar cell technology.
The findings suggest a pathway toward creating perovskite solar cells capable of reliably generating clean energy for years, potentially accelerating the transition to a more lasting energy future. Further research will focus on optimizing the lithium doping concentration and exploring its compatibility with different perovskite compositions to maximize performance and durability.
