Surface passivation with multifunctional molecules is an effective strategy to mitigate the defect and improve the performance and stability of perovskite solar cells (PSCs). Here, the fabrication of a wide bandgap-PSC is reported with tin perovskite (WB-Sn-HP; bandgap: 1.68 eV), followed by molecular surface passivation using 4-Fluoro-benzohydrazide (F-BHZ). WB-Sn-PSC has demonstrated a promising device efficiency of 11.14% with improved device stability. The key to enhancing device performance lies in the meticulous engineering of both surface and bulk properties of WB-Sn-HP film with F-BHZ treatment as a consequence of stronger electrostatic potential and molecular interaction with hydrazine and carbonyl functionalities. A compact perovskite film and highly crystalline film growth results in a longer carrier lifetime and surface defect mitigation with the control of Sn2+ oxidation as supported by theoretical calculations. This work underlines the promising potential of chemical engineering to improve the device performance of WB-Sn-PSC and stability using multifunctional passivating molecules.
Keywords: device stability; lead‐free; surface passivation; tandem device; tin oxidation; wide bandgap tin perovskite.
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