In the relentless pursuit of next-generation solar technology, low-bandgap tin–lead (Sn–Pb) perovskite solar cells have emerged as a beacon of promise thanks to their exceptional ability to harness sunlight efficiently. Positioned at the core of all-perovskite tandem solar cells—devices that combine layers of perovskite materials with different bandgaps to reap enhanced solar conversion efficiencies—these Sn–Pb perovskites are lauded for their near-ideal bandgap of approximately 1.25 eV. Despite their potential, a formidable roadblock has persisted: the rapid degradation of the precursor solutions used to fabricate these solar cells, predominantly due to the facile oxidation of tin ions from their divalent state (Sn^2+) to higher oxidation states. This oxidation severely undermines the material’s stability and, ultimately, the devices’ operational lifetime.
A recent groundbreaking study headed by Ma, Zhao, Zhu, and their team has shed unprecedented light on the underpinnings of this degradation phenomenon, offering a promising pathway to circumvent it through innovative chemical stabilization strategies. Their work meticulously deconstructs the complex oxidation reactions occurring within Sn–Pb perovskite precursor inks and pioneers the incorporation of basic amino acids and their sulfate salts—collectively termed basic amino acids sulfate (BAAS)—as highly effective proton scavengers to thwart these detrimental reactions. This advance not only brings forth unprecedented ink stability for over 300 days but also revolutionizes the long-term viability of low-bandgap perovskite solar cells.
At the heart of the issue lies the oxidative vulnerability of Sn^2+ species in the perovskite solution. The oxidation primarily arises when residual protons in the precursor ink react with dimethyl sulfoxide (DMSO) molecules, a widely used solvent, initiating deleterious chemical pathways that culminate in the oxidation of Sn^2+. Such an oxidation mechanism accelerates the formation of defects during crystallization, directly impairing the electronic properties of the resultant perovskite films. The researchers’ in-depth investigation reveals that the proton concentration within the ink is a critical lever controlling these unwanted oxidation reactions.
By ingeniously implementing BAAS additives, composed of proton-scavenging amino acids paired with sulfate ions, the team has devised a dual-action stabilization approach. First, these basic amino acids act as efficient sinks for excess protons, substantially mitigating the proton-driven oxidation pathways triggered by DMSO. Second, sulfate ions form coordination bonds with Sn^2+ centers, effectively passivating defect sites and finely tuning the crystallization kinetics during film formation. This multipronged strategy addresses both the chemical and structural vulnerabilities of the Sn–Pb perovskite precursors, culminating in highly uniform, low-defect, and stable perovskite films.
The resulting perovskite solar cells, fabricated using this BAAS-stabilized ink, exhibited a remarkable power conversion efficiency (PCE) of 24.06%, alongside an impressively maintained open-circuit voltage (Voc) of 0.905 V. These performance metrics emphasize the tremendous potential for these materials not just as standalone photovoltaic absorbers but as top-tier components within tandem architectures aiming to surpass the fundamental efficiency limits of single-junction cells. When integrated into two-terminal all-perovskite tandem solar cells, the BAAS-treated films contributed to a record certified PCE of 29.56%, with laboratory demonstrations achieving 30.24%, setting a new benchmark for perovskite photovoltaics.
Beyond the immediate boosts in efficiency, the stability profile of these BAAS-passivated devices under operational conditions represents a significant leap toward commercialization. The tandem solar cells demonstrated retention of over 85% of their initial efficiency after 1,000 hours subjected to continuous maximum power point tracking under 1-sun illumination, mimicking real-world solar exposure conditions. Such durability underscores the effectiveness of the chemical strategies in combatting intrinsic material weaknesses and heralds a new era wherein perovskite technologies may rival the lifelong reliability of conventional silicon solar modules.
This study’s success in stabilizing Sn–Pb perovskite inks unlocks new vistas not merely by enhancing material performance but by addressing one of the longstanding bottlenecks that have limited the scalability and manufacturability of these quantum-tuned absorbers. The ability to maintain ink stability over extended periods—notably more than 300 days—opens the door to industrial-scale production protocols, potentially reducing costs while ensuring consistent quality and reproducibility of films.
The use of basic amino acids and sulfate ions also subtly shifts the paradigm of defect passivation from solely ionic or electronic means to more nuanced coordination chemistry-based approaches. This insight lays a foundational framework for future rational design of perovskite inks, wherein tailored additive chemistries can be systematically screened and employed to combat a spectrum of instability mechanisms arising from diverse chemical and environmental stressors.
Furthermore, the intricate balance achieved between efficient proton scavenging and selective ion coordination highlights the delicate interplay between solution chemistry and solid-state crystallization processes. This balance is vital for producing perovskite films that exhibit not only superior optoelectronic parameters but also mechanical robustness and environmental resilience—key features for real-world deployment.
Integrating these BAAS-enhanced films into all-perovskite tandem modules directly leverages the low bandgap of the Sn–Pb perovskite without sacrificing stability or efficiency, bridging the gap between laboratory achievements and commercial viability. This successful integration marks a critical milestone in the solar industry’s quest to deliver high-efficiency, low-cost, and scalable photovoltaics capable of reducing reliance on fossil fuels.
The implications of this feat extend beyond photovoltaics, potentially inspiring analogous strategies in other tin-containing perovskite-based applications, including light-emitting diodes (LEDs), photodetectors, and radiation sensors. The approach of using multifunctional additives that simultaneously neutralize reactive species and provide defect passivation may well become a universal blueprint for stabilizing otherwise unstable materials.
Such advancements are also timely within the broader context of sustainable energy technologies, where rapid progress in material stability complements breakthroughs in device architecture and charge transport engineering. By extending the effective lifespan of Sn–Pb perovskite materials, this research addresses one of the most persistent barriers toward integrating perovskite tandem solar cells into the existing photovoltaic market and energy infrastructure.
Looking ahead, this research opens compelling opportunities to explore additional additive combinations, solvent systems, and processing protocols tailored specifically for low-bandgap perovskites. Such fine-tuning may further optimize performance parameters, push efficiencies even higher, and tailor stability profiles suited for diverse climatic conditions and deployment scenarios. Moreover, mechanistic studies probing the kinetics and thermodynamics of proton scavenging and ion coordination may deepen our foundational understanding of perovskite chemistry.
In sum, the stabilization of Sn–Pb perovskite precursor inks via basic amino acids and sulfate ions represents a seminal achievement accelerating the trajectory toward durable, high-performance all-perovskite tandem solar cells. This advance illuminates a promising path to conquer the inherent oxidation challenges of tin-based perovskites, thereby enhancing both their practical applicability and commercial appeal. In a world increasingly reliant on renewable energy solutions, such innovations are vital for translating cutting-edge materials science into impactful, sustainable technologies capable of meeting growing global energy demands.
Subject of Research:
Article Title:
Article References:
Ma, T., Zhao, Y., Zhu, J. et al. Stable tin–lead perovskite inks for efficient all-perovskite tandems. Nat Energy (2026). https://doi.org/10.1038/s41560-026-02077-8
Image Credits: AI Generated
DOI: https://doi.org/10.1038/s41560-026-02077-8
Keywords: tin–lead perovskite, low-bandgap perovskite, solar cell stability, oxidation pathways, proton scavengers, basic amino acids sulfate (BAAS), defect passivation, perovskite precursor inks, all-perovskite tandem solar cells, power conversion efficiency, crystallization regulation
