Lattice Oxygen‐Mediated Defect and Strain Regulation of SnO2 via Water‐Soluble Tb2O3 for High‐Performance Perovskite Solar Cells

Why It Matters

By eliminating defect‑induced losses and mechanical strain in SnO2 ETLs, the technique pushes PSC efficiencies toward commercial viability and extends operational lifetimes under real‑world conditions.

Key Takeaways

• Tb2O3 nanocrystals fill SnO2 oxygen vacancies via lattice oxygen.
• Composite ETL reduces surface roughness and improves carrier mobility.
• Achieved 25.95% power conversion efficiency, a record for SnO2‑based PSCs.
• Enhanced humidity and thermal‑cycling stability through strain mitigation.
• Scalable, water‑soluble pretreatment compatible with existing CBD processes.

Pulse Analysis

Perovskite solar cells have surged as a low‑cost alternative to silicon, yet their electron‑transport layer—often tin dioxide (SnO2)—suffers from intrinsic oxygen vacancies that act as non‑radiative recombination centers. These defects not only limit charge extraction but also exacerbate mechanical stress during temperature fluctuations, undermining long‑term reliability. Conventional chemical‑bath deposition (CBD) methods leave a porous SnO2 film riddled with vacancies, prompting researchers to seek passivation strategies that can be integrated without overhauling existing production lines.

The novel pretreatment leverages water‑soluble Tb2O3 nanocrystals, which introduce abundant lattice oxygen at the SnO2 interface. This oxygen replenishes vacancies, creating a more uniform SnO2‑Tb2O3 composite with lower surface roughness and higher carrier mobility. Simultaneously, the lattice‑oxygen bonding mitigates tensile strain, allowing the perovskite absorber to form larger grains with superior light‑trapping properties. The result is a dramatic boost in power conversion efficiency—25.95%—and a marked improvement in humidity tolerance, addressing two of the most critical hurdles for commercial deployment.

Beyond performance gains, the Tb2O3 approach is noteworthy for its scalability. The nanocrystals are water‑soluble, enabling a simple post‑cleaning, pre‑annealing dip that fits seamlessly into current CBD workflows. This low‑temperature, solution‑based step avoids costly vacuum equipment and can be adopted across large‑area manufacturing. As the photovoltaic market seeks both high efficiency and durability, such defect‑engineered ETLs could accelerate the transition of perovskite technology from laboratory prototypes to market‑ready modules, reshaping the competitive landscape of renewable energy.