Interfacial Engineering of Triple Cation Perovskite Solar Cells Using Graphitic Carbon Nitride‐Modified Hematite Electron Transport Layer for Enhanced Photovoltaic Performance
Аннотация
Organic–inorganic halide perovskite solar cells (PSCs) demonstrate impressive power conversion efficiencies (PCEs), yet they encounter significant issues concerning interfacial defects and stability. This work mitigates these constraints by implementing a dual interfacial passivation approach utilizing graphitic carbon nitride (g‐C 3 N 4 ) at the interfaces of the Fe 2 O 3 electron transport layer (ETL)/CsFAMA perovskite (PVK) and PVK/hole transport layer (HTL). The Fe 2 O 3 ETL, despite its chemical stability and cost‐effectiveness, is hindered by surface roughness and trap states that impede efficient charge extraction. Through the incorporation of g‐C 3 N 4 , a nitrogen‐rich 2D semiconductor, we attained defect passivation through coordination with undercoordinated Pb 2+ ions and halide vacancies, thereby inhibiting ion migration and improving interfacial energy alignment. Structural characterization (XRD, Raman, scanning electron microscope [SEM]) confirms the layered morphology of g‐C 3 N 4 and its compatibility with the PVK matrix, while optical analysis reveals enhanced light absorption (400–550 nm) and retained transparency (~80%). The dual‐modified devices achieved a champion PCE of 15.97% (12.89% for the control) and a low hysteresis index (HI) of 0.01 (0.06 for the control) with a high V OC = 1.12 V, J SC = 19.49 mA cm −2 , and FF 73.19%. Electrochemical impedance spectroscopy and photoluminescence studies demonstrate reduced charge recombination and improved carrier extraction. Critically, the modified devices retain approximately 87% of their initial PCE after 500 h under continuous illumination, highlighting exceptional operational stability. This work establishes dual interfacial engineering with g‐C 3 N 4 as a robust strategy for advancing efficient, hysteresis‐free, and durable PVK photovoltaics, bridging the gap toward commercial viability.
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