Interfacial Engineering of Triple Cation Perovskite Solar Cells Using Graphitic Carbon Nitride‐Modified Hematite Electron Transport Layer for Enhanced Photovoltaic Performance
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Annotatsiya
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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