Mitigating VOC Loss in Single-Junction and Four-Terminal Tandem Perovskite/Si Photovoltaics with D-A Phthalocyanines Layers

The performance of perovskite solar cells (PSCs) is often constrained by significant open-circuit voltage (V-OC) losses attributed to non-radiative recombination processes induced by detrimental trap states. Surface treatments using passivating ligands typically involve single active binding sites on perovskite, posing challenges for effective passivation. Here, an aromatic donor-acceptor (D-A) configured phthalocyanine treatment is proposed to aim at dual-site passivation of uncoordinated lead ions and effective mitigation of shallow and deep-level defects on the perovskite surface. The resulting benign p-type surface facilitates a more favorable energy level alignment and reduces energetic mismatches at the perovskite/Spiro-OMeTAD interface. Pc-BTBC, with its aromatic D-A configuration, demonstrated compatibility with various perovskite compositions. Optimized PSCs achieves a power conversion efficiency (PCE) of 25.15% and reduces the V-OC deficit to 0.379 V. Furthermore, encapsulated devices exhibited enhanced stability under damp-heat conditions (ISOS-D-2, 50% RH, 65 degrees C) with a T-92 of 1000 h and maintained maximum power point tracking under continuous light in ambient air at 65 degrees C (ISOS-L-2). Notably, fabricated wide-bandgap semitransparent PSCs (ST-PSCs) achieved a PCE of 20.29%, while four-terminal perovskite/silicon tandem solar cells (4T-P/STSCs) demonstrated an efficiency of 29.38%. This study provides insights into minimizing V-OC losses and represents significant progress toward commercializing perovskite photovoltaics.