Liang Chao from Xi’an Jiaotong University: AM: 26.34%! 21.94% at 69 cm²! Tunable charge polarization at the interface drives breakthroughs in efficiency and stability!

Local charges at the interface and interfacial losses arising from incompatibilities in the underlying layers are key factors that limit the efficiency enhancement and market penetration of perovskite solar cells (PSCs).

Based on this, Yang Shengchun, Liang Chao, and their colleagues at Xi’an Jiaotong University have proposed a novel interface-chemical modulation strategy that involves proton transfer between the amino group of pyridoxamine (PM) and the phosphonic acid anchoring moiety of [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz), while simultaneously enhancing charge delocalization through electrostatic attraction between oppositely charged molecules. The Me-4PACz–PM charge-polarized interface can modulate the charge state of nickel oxide (NiOx) and the coordination environment at the buried interface, thereby boosting p-type conductivity and achieving a more optimal band alignment. Furthermore, the high coverage and excellent wettability of the NiOx/Me-4PACz–PM interfacial layer facilitate the deposition of high-quality perovskite films, relieve lattice strain, and reduce trap-assisted non-radiative recombination. Thanks to the implementation of this tunable charge-polarized interface, small-area devices and modules with an area of 69 cm² have achieved power conversion efficiencies (PCE) of 26.34% (certified efficiency: 25.48%) and 21.94% (certified efficiency: 20.50%), respectively; moreover, unencapsulated devices retain approximately 90% of their initial PCE after 2,000 hours of aging under the ISOS-L-1 protocol and 1,500 hours of aging under the ISOS-D-1 protocol. This work was recently published in the journal Advanced Materials under the title “Charge Polarization Tunable Interfaces for Perovskite Solar Cells and Modules.”

In summary, the authors have proposed a molecular-level chemical fine-tuning strategy based on Me-4PACz, which enables the formation of a dipolar interface with outstanding interfacial contact properties and strong charge polarization. Specifically, the –PO(OH)₂ anchoring group in Me-4PACz undergoes proton transfer with the amine groups of PM, thereby breaking the original symmetry of Me-4PACz; the resulting electrostatic attraction between oppositely charged molecules induces favorable charge delocalization. The resulting Me-4PACz–PM charge-polarized interface optimizes charge distribution, improves the Ni coordination environment, and the increased Ni vacancies significantly enhance p-type conductivity while achieving a more advantageous band alignment. Furthermore, the highly conformal and well-wetted Me-4PACz–PM underlayer alleviates lattice strain within the film, effectively enhancing perovskite film quality and reducing trap-assisted recombination. On the basis of NiOx/Me-4PACz–PM, small-area devices and modules with an area of 69 cm² achieved champion efficiencies of 26.34% (certified efficiency: 25.48%) and 21.94% (certified efficiency: 20.50%), respectively—among the highest power conversion efficiencies reported for solar modules of this scale. In addition to markedly improved stability, this chemically precise tuning strategy is broadly applicable to Me-4PACz-based self-assembled monolayers as well as to perovskite compositions with other bandgaps. The successful scaling of the tunable charge-polarized interface to large-area modules provides valuable insights for commercial applications and serves as a reference for refined interface engineering.

Device Structure ：

ITO/HTL/PVSK/PEACl/C₆₀/BCP/Ag

1. Wash the ITO glass thoroughly, then treat it with ozone for 20 minutes; spin-coat a 10 mg/mL NiOx solution in ultrapure water at 4000 rpm for 30 seconds, followed by annealing in air at 100°C for 10 minutes; dissolve 0.5–2 mg/mL Me-4PACz and 0–0.3 mg/mL PM in ethanol, stir the mixture, then spin-coat at 3000 rpm for 30 seconds, followed by annealing at 100°C for 10 minutes; rinse with ethanol, spin-coat again at 3000 rpm for 30 seconds, and anneal at 100°C for 5 minutes.

2. 1.6 M Cs _0.05 Master of Arts _0.05 FA _0.90 Lead iodide ₃ Dissolve in DMF:DMSO = 4:1 (v/v) + an additional 5% MAPbCl ₃ Spin-coat at 1000 rpm for 10 s, then at 4000 rpm for 30 s; during the final 10 s, add 180 µL of CB anti-solvent, followed by annealing at 100°C for 15 min.

3. 1 mg/mL PEACl IPA, spin-coated, annealed at 100°C for 5 min;

4. Vapor deposition of 25 nm C ₆₀ ; 7 nm BCP; 100 nm Ag.

Module Preparation:

1. ITO substrate, P1 etching with a 532 nm green laser; specific process parameters are as follows: average laser power of 15.4 W, spot diameter of 25 μm, pulse frequency of 110 kHz, scribing speed of 800 mm/s, scribing line width of 100 μm; after etching, the sample is rinsed thoroughly with ozone for 20 minutes.

2. 10 mg/mL NiOx in ultrapure water, spin-coated at 4000 rpm for 30 s, followed by annealing at 100°C for 10 min; 1 mg/mL Me-4PACz plus 0.2 mg/mL PM dissolved in EtOH, spin-coated at 3000 rpm for 30 s, followed by annealing at 100°C for 10 min;

3. Perovskite spin-coating is performed as described above, with the anti-solvent volume increased to 1200 µL;

4. Vapor deposition of 25 nm C ₆₀ ; 7 nm BCP; P2 etching: average laser power of 16.8 W, spot diameter of 25 μm, pulse frequency of 120 kHz, dicing speed of 800 mm/s, scribe line width of 100 μm, performed twice;

5. Evaporate 100 nm of Ag; P3 etching: set the parameters as follows: average laser power of 19.6 W, spot diameter of 25 μm, pulse frequency of 140 kHz, scribing speed of 600 mm/s, scribing line width of 100 μm, and perform the process twice.