Perovskite solar cells (PSCs) represent a promising next-generation photovoltaic technology due to their excellent intrinsic optoelectronic properties. However, significant challenges remain regarding long-term device stability and current-voltage hysteresis. These issues frequently originate at the interface of the electron transport layer (ETL) and the perovskite absorber. Traditional ETL materials like titanium dioxide and zinc oxide exhibit drawbacks such as low electron mobility, photocatalytic degradation, and inherent chemical instability that limit practical application.

Tin oxide (SnO₂) has emerged as an attractive alternative ETL material owing to its high electron mobility, low-temperature processing, and robust chemical stability. Despite these advantages, intrinsic defects in SnO₂ films, such as oxygen vacancies, can induce non-radiative recombination and hinder electron transport. Addressing these defect states through interface engineering is therefore essential to unlocking higher PSC performance.

To overcome these limitations, this study investigated the integration of multilayer SnO2 architectures into planar PSCs. The researchers fabricated three distinct ETL configurations: a reference bilayer (1A1C) consisting of one amorphous and one crystalline layer, a 1A2C structure (one amorphous, double crystalline stack), and a 2A1C structure (double amorphous, single crystalline layer).

Structural and photovoltaic analyses revealed that the 1A2C configuration significantly outperformed the others, achieving a power conversion efficiency of 15.33% compared to 12.16% for the 1A1C reference. This enhanced performance is attributed to the 1A2C structure providing a smoother surface morphology and better wettability, which promoted uniform perovskite nucleation and minimized pinhole formation. Furthermore, the optimized configuration improved charge collection and successfully suppressed carrier recombination at the ETL/perovskite interface.

In summary, carefully controlling the stacking sequence of amorphous and crystalline SnO2 layers presents a simple and effective strategy for enhancing device efficiency. This architectural optimization offers valuable insights for advancing the stability and performance of ambient-air processed perovskite solar cells.

Source:

Nur Farah Hanun Wira, Kai Jeat Hong, Chi Chin Yap, Kok-Keong Chong, Josephine Ying Chyi Liew, Hock Beng Lee, Jae-Wook Kang, Mohammad Hafizuddin Hj Jumali, Mohd Hafiz Mohd Zaid, Sin Tee Tan. Effect of multilayer SnO2 architectures on charge transport and optical properties in triple-cation perovskite solar cells, Optical Materials, Volume 174, 2026,

https://doi.org/10.1016/j.optmat.2026.117947.

Date of Input: 28/04/2026 | Updated: 28/04/2026 | roslina_ar