Amplifying Hole Extraction Characteristics of PEDOT:PSS via Post-treatment with Aromatic Diammonium Acetates for Tin Perovskite Solar Cells

Wemodify the PEDOT:PSS hole transport layer (HTL), commonly adoptedfor high-performance tin perovskite solar cells (TPSCs), via post-treatmentof its surface using aromatic diammonium acetate salts dissolved ina highly volatile but interactive solvent. The solvent partly etchesexcessive insulating PSS while enabling tight anchoring of the saltsto the PEDOT:PSS HTL. The salts improve not only the PEDOT:PSS/perovskiteinterface but also the top surface of tin perovskite thin films, leadingto reduced interface defects, larger built-in potentials, and suppressedperovskite pinhole defects. In addition, the salts transform the PEDOTstructure from benzoid to quinoid and depopulate excessive hole chargecarriers to promote hole extraction. Consequently, TPSCs attain ahigh efficiency of 12.1% under standard 1 sun light illumination andimpressive stability without encapsulation for & SIM;2800 h underan N-2 atmosphere. We developed a straightforward but impactfulmethod to modify PEDOT:PSS for broader applications.