2025-12-19 シンガポール国立大学（NUS）
＜関連情報＞
- https://news.nus.edu.sg/vapour-deposited-perovskite-silicon-tandem-solar-cells/
- https://www.science.org/doi/10.1126/science.adz3698
高安定性タンデム太陽電池のためのテクスチャシリコン上の最適なペロブスカイト蒸気分割 Optimal perovskite vapor partitioning on textured silicon for high-stability tandem solar cells
Nengxu Li, Xiuxiu Niu, Zijing Dong, Jingcong Hu, […] , and Yi Hou
Science Published:18 Dec 2025
DOI:https://doi.org/10.1126/science.adz3698
Editor’s summary
Perovskites can be vapor deposited as conformal films on industry-standard silicon substrates with micropyramid textures. Li et al. demonstrated that coating silicon with trimethoxysilane-bearing, electron-rich fluorine atoms strengthened organic substrate bonding. The compositional balance of films was maintained during coevaporation of lead iodide, cesium bromide, and formamidinium iodide. Tandem solar cells had a power conversion efficiency of 31.3% for a 1-square-centimeter aperture area and retained 90% of this efficiency after 1400 hours of continuous 1-sun illumination at 85°C. —Phil Szuromi
Structured Abstract
INTRODUCTION
Perovskite–silicon tandem solar cells have achieved lab efficiencies approaching 35%. Yet, their transition to commercialization is hindered by two major challenges: incompatibility and instability. Conventional solution processing for perovskites remains confined to custom-textured wafers (with submicrometer pyramids), posing substantial hurdles for scalable, high-throughput manufacturing. Meanwhile, wide-bandgap perovskites in tandem architectures suffer accelerated degradation, with operational lifetimes rarely exceeding 2000 hours. Overcoming these bottlenecks is essential for translating record efficiencies into durable, manufacturable technologies.
RATIONALE
Vapor deposition offers a promising route compatible with industrially textured silicon wafers (with micrometer-scale pyramids), where conformal perovskite growth could theoretically enhance both efficiency and stability. However, forming high-quality films on such wafers remains challenging owing to imbalanced adsorption of precursor vapors: Organic species (such as formamidinium, FA+) interact weakly with the substrate, leading to reduced adsorption relative to inorganic counterparts. Moreover, the microscale-textured surface exacerbates this adsorption imbalance, resulting in poor perovskite film quality with pronounced phase impurities. Substrate surface functionalization is therefore critical to strengthen organic–substrate interactions and achieve balanced adsorption across all components.
RESULTS
The functional molecule 3,3,3-trifluoropropyl-trimethoxysilane (TFPTMS) was designed to selectively strengthen interactions with organic components. It features two distinct terminal groups: fluorine atoms that facilitate F•••H–N hydrogen bonding with –NH2 groups in organic cations (FA+), and a trimethoxysilane group that enables self-assembly on the substrate for stable, oriented attachment. Density functional theory calculation confirmed that TFPTMS could enhance the adsorption energy of organic species. Experimentally, TFPTMS-functionalized silicon substrates produced perovskite-rich interfacial compositions, confirmed by x-ray diffraction, x-ray photoelectron spectroscopy, and nanobeam diffraction. This is attributed to improved adsorption of organic cations, leading to more stoichiometric perovskite formation. By contrast, control samples without functionalization exhibited PbI2-rich phases because of insufficient organic adsorption. Leveraging improved film quality from TFPTMS-modulated adsorption dynamics, perovskite–silicon tandem solar cells achieved power conversion efficiencies exceeding 31% on industrially textured silicon wafers with enhanced reproducibility. Furthermore, the devices maintained >2000 hours of operational stability under continuous 1-sun operation at room temperature and demonstrated a T90 lifetime exceeding 1400 hours under 1-sun operation at 85°C.
CONCLUSION
Achieving equilibrium vapor partitioning on textured silicon is a prerequisite for forming high-quality perovskite films and ensuring better device performance. Our studies reveal that organic species such as FA+ interact weakly with pyramid-textured surfaces, resulting in insufficient adsorption and the emergence of phase impurities. To overcome this limitation, we introduced a dual-functional molecule combining a trimethoxysilane anchor with electron-rich atoms (e.g., fluorine), which strengthens organic–substrate bonding and restores compositional balance during coevaporation. Devices fabricated with this approach reached superior stability under demanding stress tests, including high-temperature operation. This robustness stems from improved film uniformity that alleviates microstrain, thereby suppressing ion migration and lattice distortion, together with a reduction of residual PbI2 impurities at the buried interface, which limits potential degradation sites. These synergistic effects endow the tandem devices with long-term operational stability under harsh conditions.
Conformal growth of perovskite layer on industrially textured silicon wafer.
We use vapor-based coevaporation to conformally deposit high-quality perovskite layers on pyramid-textured silicon substrates, yielding perovskite–silicon tandem solar cells with enhanced efficiency, stability, and reproducibility.
Abstract
Achieving conformal, vapor-deposited perovskite films on industry-standard textured silicon substrates with micrometer-scale pyramids remains challenging because of the complex surface partitioning of perovskite vapors and the effects of nonequilibrium organic and inorganic vapor adsorption. We incorporated 3,3,3-trifluoropropyl-trimethoxysilane to enhance substrate-organic interactions, thereby optimizing surface partitioning and balancing adsorption of perovskite vapors. Vertically uniform perovskite films with minimal phase impurities formed, and nanobeam diffraction confirmed formation of the perovskite cubic phase across different pyramid regions. The resulting tandem devices achieved a power conversion efficiency of 31.3% (1 square centimeter aperture area) and exhibited excellent operational stability, retaining 90% of their initial performance after 1400 hours of continuous 1-sun illumination at 85°C.
