Peroxo-route Synthesis of Stable and Surfactant-free SnO2 Colloids for Perovskite Solar Cell Electron Transport Layer

doi:10.15541/jim20260122

Abstract

Abstract: Tin dioxide (SnO₂) colloid is critical for high-performance perovskite solar cells (PSCs), which depends on the grain size and properties of SnO₂ nanocrystals (NPs). However, SnO₂ suffers from intrinsic oxygen vacancies and particle aggregation, which lead to poor film quality as an electron transport layer (ETL). Wet chemical methods using organic surfactants introduce residual impurities that exacerbate interfacial defects and degrade the performances of PSCs. This work reported a surfactant-free SnO₂ colloid synthesis via a peroxo-route, combining hydrogen peroxide peptization and hydrothermal growth to achieve ultrafine and highly crystalline nanoparticles (~3 nm in diameter) with lower oxygen vacancies. SnO₂ NPs were further evolved into nanorods with aspect ratio (AR) to 3.02±0.42 under the hydrothermal temperature of 120-180 ℃ due to oriented attachment growth. Tailoring hydrothermal temperature and duration yielded a mixture of nanorods and nanoparticles, enhancing interfacial compaction for the SnO₂ film. When those serviced as ETL in n-i-p structured PSCs with FA_0.85MA_0.15Pb(I_0.85Br_0.15)₃ as the perovskite layer, the resulting films have denser grain packing, which enhances electrical connectivity, increases hydrophilicity and reduces surface roughness. The devices achieve a power conversion efficiency (PCE) of 23.99%, while the unencapsulated PSCs retain 93.5% of initial efficiency after 30 d under ambient conditions (30% relative humidity (RH)), showing superior performance over the commercial SnO₂-based counterparts (84.5%). The methodology establishes an environmentally friendly technology for high-performance SnO₂nanocrystals, addressing both the mitigation of interfacial defect and the challenges of scalable production in next generation photovoltaics.

Key words: tin dioxide colloid, peroxo-route synthesis, perovskite solar cell, electron transport layer, oriented attachment

CLC Number:

TM914

ZHAO Ziqi, ZHANG Mengmeng, LI Kerui, HOU Chengyi, LI Yaogang, WANG Hongzhi, ZHANG Qinghong. Peroxo-route Synthesis of Stable and Surfactant-free SnO₂ Colloids for Perovskite Solar Cell Electron Transport Layer[J]. Journal of Inorganic Materials, DOI: 10.15541/jim20260122.

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Peroxo-route Synthesis of Stable and Surfactant-free SnO₂ Colloids for Perovskite Solar Cell Electron Transport Layer

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