Perovskite synthesis out in the open: Although methods have been developed that create the photoactive black perovskite phase of formamidinium lead iodide (α-FAPbI ₃ ), these routes are temperature and humidity sensitive and less compatible with large-scale solar cell production. Hui et al. report an alternative route in which vertically aligned lead iodide thin films are grown from the ionic liquid methylamine formate. Nanoscale channels in the films lower the barrier to permeation of formamidinium iodide and enable transformation to α-FAPbI ₃ , even at high humidity and room temperature. Solar cells made with these films have power conversion efficiencies as high as 24.1% that display high stability. Science , this issue p. 1359

Preparation of low defect density FAPbI₃ perovskite thin films by adjusting the process temperature to −20 °C for high-performance perovskite solar cells.

Low-dimensional conversion of lead iodide at perovskite grain boundaries (GBs) is of importance to address the interfacial instability of perovskite solar cells (PSCs), while current strategies relying on organic cations interacted with A/X site to low-dimensional lead-halide complexes are challenged by the instability caused by the introduction or residual cations and halides in perovskite films. Present work proposes and verifies a strategy of multidentate carbodithioate-lead chelation (MCLC), which is able to form a robust one-dimensional structure at the GBs, not only reducing interfacial defects and residual stress but also enhancing interfacial carrier transport in perovskite while substantially improving the photothermal and operational stabilities of PSCs. It was further demonstrated that bifacial modification at both top and buried interfaces of perovskite using MCLC strategy achieved PSCs with a high power conversion efficiency up to 26.15% (certified value of 25.75%) and 24.89% for 1-cm ² -area device. The device retains 90.1% of its initial efficiency after 1700 hours of maximum power point tracking under illumination.

Doping of bis(trifluoromethane)sulfonimide (LiTFSI) and 4-tert-butylpyridine (TBP) in 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene (Spiro-OMeTAD) is currently considered irreplaceable for fabricating high-performance perovskite solar cells (PSCs). However, the stability of Spiro-OMeTAD was demonstrated to be seriously limited by the Li⁺ diffusion of LiTFSI and the volatilization of TBP. Herein, we report a strategy of doping with an organic molten salt, cyclohexylamine trifluoroacetic acid (CYTFA), to stabilize doped Spiro-OMeTAD for high-performance PSCs. We found that Li⁺ diffusion and TBP volatilization were effectively suppressed through strong interactions of dissociated CY⁺ and TFA⁻ acting on TBP and Li⁺. Moreover, CYTFA-doped Spiro-OMeTAD exhibits an order of magnitude increase in hole mobility and matched energy levels with perovskites. As a result, a solar cell with a power conversion efficiency of 25.80% was achieved, maintaining 96% and 80% of the initial efficiency for 500 hours at 55 °C and 55% humidity and for 470 hours at the maximum power point, respectively.

A pre-nucleation strategy, which involves controlling the precursor solution at the molecular level during the preparation of AgBiS₂ solar cells by the solution method, achieves a record power conversion efficiency of 3.6%.

Interfacial dipolar molecules play a crucial role in achieving high-performance perovskite solar cells (PSCs). However, the random distribution at the interface often limits their ability to effectively regulate interfacial energy levels and carrier extraction. Here, we report a bifunctional antisymmetric molecule, N-(1-carboxyethyl)iminodiacetic acid trisodium salt (MGDA·3Na), which enables both directional alignment and stable anchoring on SnO₂ and perovskite interfaces. The methyl side chain in the MGDA^- anion induces intramolecular electronic polarization and dipole reorientation, facilitating selective adsorption on the SnO₂ surface and perovskite buried interface. This significantly improves interface uniformity, enabling efficient passivation of SnO₂ surface defects and precise regulation of perovskite crystal growth. The dual anchoring effect not only aligns energy levels to minimize charge extraction barriers but also templates vertical perovskite growth, reducing buried interface defects and enhancing crystallization quality. As a result, we achieved a power conversion efficiency of 26.43% in small-area PSCs and 23.27% in a 5 × 5 cm² large-area module, highlighting the potential for industrial-scale application. The device maintains 96% of its initial efficiency for 2000 h under nitrogen-filled glove box, 96% after 800 h at 55 °C/55% RH, and 99% after 800 h of continuous illumination at the maximum power point.