Metal halide perovskites have emerged as one of the most promising classes of materials in modern photovoltaics. Despite this rapid ascent, critical barriers remain on the path to commercialization: long-term operation longevity, large-scale processability and safer alternatives continue to challenge researchers.

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In this issue, Nature Nanotechnology highlights studies that collectively demonstrate how the principles and techniques of nanoscience accelerate the journey of perovskite photovoltaics from the laboratory to market. Rather than treating the challenges of perovskite photovoltaics as isolated materials or device problems, these works show how controlling matter at the nanoscale can reveal new insights in physical chemistry that can be leveraged to design better devices and improve performance.

In solution-processed perovskites, the microstructure of thin films governs charge-carrier dynamics and long-term stability. In the case of formamidinium lead iodide (FAPbI3), the phase transformation from the non-photovoltaic δ-phase to the desired α-phase requires delicate thermal and chemical tuning. The traditional additive process introduces a longstanding dilemma: Lewis bases must bind strongly enough to stabilize the intermediate phase but be released quickly to allow the transformation to the final phase. To address this issue, the Article by Fu et al. introduces an on-demand Lewis base formation strategy. Instead of relying on permanent or pre-existing additives, the authors use semicarbazide hydrochloride, a Lewis-acid-containing salt, that dynamically generates Lewis base molecules in situ through reversible deprotonation. Temporally and spatially controlling chemical reactivity at the nanoscale reconciles the thermodynamic and kinetic constraints in perovskite additive design.

Another compelling case through additive engineering is reported in the Article by Fu et al. for tandem devices. All-perovskite tandem solar cells composed of wide-bandgap and narrow-bandgap subcells are particularly attractive due to their compatible materials systems and solution processability. Yet, scaling these devices to industry-scale without performance degradation remains a formidable hurdle. In their work, the authors introduce piracetam, a pyrrolidone base, as a multifunctional agent that acts at multiple stages of film formation. Piracetam's dual role as a structure-directing agent and defect passivator at the nanoscale simultaneously improves scalability and stability in tandem solar cells.

While lead-based perovskites continue to dominate the performance leaderboard, environmental concerns around lead toxicity have fuelled interest in tin halide perovskite alternatives. Yet, these materials suffer from poor film formation and rapid oxidation. In their Article, He et al. tackle this challenge through a nanoscale chemical perspective — synchronizing the nucleation kinetics of two- and three-dimensional (2D/3D) domains in solution by incorporating small caesium cations into the electrical double layers of perovskite colloids. This reduces electrostatic repulsion and promotes homogeneous 2D/3D heterostructured films with significantly reduced trap density. The fabricated device achieves a notable certified power conversion efficiency of 16.65% and exhibits over 1,500 hours of stable operation under continuous illumination without encapsulation. As highlighted in the accompanying News & Views, this colloidal chemistry approach — engineering nanoscale intermolecular interactions — offers insights for broader applications across mixed-dimensional optoelectronic systems.

Chemical and processing innovations have driven much of the recent progress in perovskite photovoltaics, while a lingering fundamental question persists: why do certain compositional variants, particularly those based on formamidinium (FA+), consistently outperform their methylammonium (MA+)-based counterparts? The answer may lie not in average crystallographic structures, which often appear similar, but in hidden local orders that govern carrier dynamics and defect tolerance.

In their Article, Dubajic et al. combine advanced characterization techniques with machine learning-guided molecular dynamics to explore the nanoscale structure of MA- and FA-based lead halide perovskites. Their findings overturn conventional assumptions about structural homogeneity. Although both systems adopt cubic symmetry at room temperature, they host fundamentally different dynamic nanodomains. MA-based materials exhibit densely packed, anisotropic planar domains with out-of-phase octahedral tilting, while FA-based perovskites display sparse, isotropic spherical domains with in-phase tilting. These subtle differences in local symmetry and dynamics translate into lower dynamic disorder in FA-based systems, leading to enhanced carrier mobility, reduced recombination, and ultimately superior device performance. This study calls for a redefinition of structure–property paradigms in perovskites, emphasizing the role of nanoscale dynamics and disorder as central design variables.

Taken together, all these works articulate a joint vision toward a more rounded framework for perovskite research — one that integrates materials physics, colloidal chemistry, crystallography, device engineering, and computational modelling. Moreover, they reinforce the idea of looking beyond bulk properties and embracing the complexity — and opportunity — hidden at the nanoscale.