Opportunity
The commercialization of perovskite solar cells (PVSCs) faces a significant hurdle due to the toxicity of lead in state-of-the-art, high-efficiency lead halide perovskite materials. While tin perovskites have emerged as a promising lead-free alternative due to favorable optoelectronic properties like a suitable band gap and high carrier mobility, they suffer from two critical deficiencies compared to their lead-based counterparts. First, there remains a substantial efficiency gap, leading to considerable energy loss. Second, tin perovskites exhibit poor long-term stability, primarily due to issues like tin oxidation and high defect densities at surfaces and interfaces. These problems of inferior power conversion efficiency (PCE) and instability directly impede the development of viable, environmentally friendly photovoltaic technologies. Therefore, there is a pressing need for innovative strategies that simultaneously enhance both the efficiency and the operational stability of tin-based perovskite solar cells to make them competitive for real-world applications.
Technology
This patent presents a comprehensive, synergistic strategy to fabricate high-performance, lead-free tin perovskite solar cells. The core innovation involves a multi-faceted approach combining component optimization, crystallization regulation, and interface functionalization. The technology utilizes a specific tin-based perovskite composition with the empirical formula Cs_xEDA_yFA_1-x-2ySnI_3, where EDA (ethylenediamine) is incorporated. This composition, particularly exemplified by FA_0.96EDA_0.02SnI_3, stabilizes the perovskite crystal structure and suppresses bulk defects and tin oxidation. The key technological advancement is the introduction of a surface treatment layer between the perovskite active layer and the electron transport layer (ETL). This layer contains a functionalized fullerene derivative, such as C_60-BPy (fullerene-n-butyl-pyridine). This derivative acts as an interfacial modifier that strongly anchors to the perovskite surface via coordination bonds between its pyridine group (a Lewis base) and Sn^2+ ions. This interaction effectively passivates surface defects, minimizes non-radiative recombination losses, and optimizes the energy level alignment at the critical perovskite/ETL interface. The result is significantly improved electron extraction and reduced charge carrier recombination.
Advantages
- Achieves a high power conversion efficiency (PCE) of up to 14.14% for tin-based PVSCs, significantly closing the gap with lead-based devices.
- Exhibits excellent operational stability, retaining over 95% of initial PCE under continuous one-sun illumination for 1000 hours and over 80% after 1000 hours of thermal aging at 80°C.
- Effectively suppresses tin oxidation and reduces both bulk and interfacial defect densities.
- Minimizes non-radiative recombination and hysteresis in current-voltage characteristics.
- Utilizes a synergistic design (composition + interface engineering) for a more robust and efficient device architecture.
- Provides an environmentally friendly, lead-free alternative for perovskite photovoltaics.
Applications
- Manufacturing of high-efficiency, stable, and non-toxic perovskite solar panels for residential, commercial, and utility-scale solar power generation.
- Development of lightweight and flexible photovoltaic devices for portable electronics, wearable technology, and building-integrated photovoltaics (BIPV).
- As a key component in tandem solar cells, where the tin perovskite can serve as a low-bandgap bottom cell paired with a wider-bandgap top cell.
- Potential use in specialized photodetectors and other optoelectronic devices requiring stable, solution-processable semiconductors.
