Halide segregation and interfacial non-radiative recombination in wide-bandgap (1.78 eV) perovskite top cells remain the primary operational bottleneck limiting monolithic perovskite/silicon tandem photovoltaics. Here, we introduce a zwitterionic pseudohalide surface-anchoring molecular dipole that simultaneously suppresses photo-induced iodide migration and passivates under-coordinated Pb(II) defect states at the electron-transport interface. Across 140 encapsulated devices, quasi-Fermi level splitting improves by 68 meV, enabling a certified stabilized power conversion efficiency (PCE) of 31.4% (active area 1.04 cm²) and T90 operational stability exceeding 1,850 hours under ISOS-L-2 maximum power point tracking at 65 °C.
Monolithic two-terminal perovskite/silicon tandem solar cells have surpassed the detailed-balance Shockley–Queisser limit of single-junction silicon (29.4%). However, wide-bandgap (WBG, 1.75–1.80 eV) mixed-halide perovskites suffer from photo-induced phase segregation into I-rich low-bandgap trap domains under continuous illumination.
Density functional theory (DFT) calculations and X-ray photoelectron spectroscopy (XPS) reveal a Pb–SCN–sulfonate bidentate coordination mode with a binding energy of -2.41 eV, increasing the vacancy-mediated halide migration activation barrier from 0.29 eV (control) to 0.64 eV.
Champion tandem cells achieve Voc = 1.982 V, Jsc = 20.14 mA/cm², FF = 78.7%, and certified stabilized PCE = 31.4%. Encapsulated ISOS-L-2 MPP tracking (65 °C, 1 sun LED) retains 90% of initial efficiency after 1,850 hours.
Pending author upload of revised After Manuscript.
0000-0002-5519-0012 ·
[ORIGINAL REVIEWER · Round 1 on v1]
Public Evaluation: An exceptionally rigorous experimental study. The certified 31.4% stabilized efficiency and 140-device statistical distribution set a high benchmark for wide-bandgap perovskite passivation.
Technical Critique / Verification Checklist: Please include the forward-to-reverse J-V hysteresis index distribution across the 140 devices in Supplementary Table S2 and clarify the exact relative humidity during the ISOS-L-2 chamber test.
0000-0001-7782-9930 ·
[ORIGINAL REVIEWER · Round 1 on v1]
Public Evaluation: The XPS and GIWAXS characterization convincingly proves that the zwitterionic dipole suppresses halide segregation without forming an insulating 2D barrier.
Technical Critique / Verification Checklist: In Section 2, please report the uncertainty bounds on the Arrhenius activation energy fit (0.64 ± 0.04 eV) from temperature-dependent conductivity measurements.