Lixing Li

Unbalanced crystallization kinetics in mixed Sn‐Pb perovskite cause film heterogeneity and high defect densities, thereby constraining overall performance and stability, particularly under scalable processing conditions. Here, we investigate nanocrystal‐mediated crystallization regulation in ambient‐processed, slot‐die‐coated narrow‐bandgap Sn‐Pb perovskites by combining CsPbI ₃ nanocrystal‐assisted processing with time‐resolved in situ grazing‐incidence wide‐angle X‐ray scattering (GIWAXS). After nine ISOS‐T‐3 thermal cycles, the perovskite solar cells (PSCs) fabricated from seeded perovskite films retain 80% of their initial efficiency at 25°C. Operando GIWAXS reveals differences in lattice evolution, residual PbI ₂ formation, and microstrain accumulation between the control and nanocrystal‐assisted films. By linking scalable processing and crystallization kinetics to the subsequent lattice response under thermal cycling, this work establishes a processing, crystallization, structure, stability relationship for narrow‐bandgap Sn‐Pb perovskites and highlights the importance of controlling early‐stage film formation for thermally robust, scalable perovskite photovoltaics.

Ultraviolet (UV) light‐induced curing is widely used in additive manufacturing and coatings. However, the formation and heterogeneous distribution of nanostructures induced by UV‑curing remain unclear, especially in submicrometer films where nanoscale precision is critical. We employ a combination of UV‐curing and X‐ray scattering to gain access to the nanoscale kinetics during UV‐curing inside the resin films used for additive manufacturing. We show that the heterogeneous distribution stems from monomer‑rich and oligomer‑rich nanodomains in solvent‑based UV‑curable resins. We further reveal how these nanodomains interact with subsequently deposited resin to form nanoscale buried interfaces using grazing incidence small‐angle X‐ray scattering. By introducing stressed‐state and relaxed‐state films based on substrate constraint, we explain the formation of buried frozen nanowrinkles in bilayer systems. Using relaxed‐state films, we identify non‑diffused, diffused, and semi‑diffused interlayer interfaces from oligomer‑rich domain interactions. This work systematically elucidates the formation mechanisms and types of interlayer nanostructures in UV‑curing based submicrometer additive manufacturing, paving the way for polymer‐based additive manufacturing with nanoscale precision resolution.

Composite solid polymer electrolytes (CSPEs) have emerged as promising candidates for next-generation lithium metal batteries. However, the spatial evolution of the solid electrolyte interphase (SEI) at solid-state interfaces remains poorly understood despite its critical role in lithium metal stability. Herein, the anion-trapping layered double hydroxide (LDH) is introduced to poly(ethylene oxide)-based CSPEs to regulate Li+ transport and stabilize the lithium/electrolyte interface. The LDH-enhanced electrolyte achieves exceptional cycling stability over 950 h with a lithium electrode and 90.1% capacity retention after 250 cycles in LiFePO4||Li full cells. Operando nano-focus wide-angle X-ray scattering maps the spatial distributions of both the SEI and lithium dendrites at the lithium/electrolyte interface across micron-scale lateral and vertical dimensions. The regulated Li+ flux promotes homogeneous lithium deposition and the formation of a robust, multifunctional SEI, thereby suppressing lithium dendrite growth and stabilizing the interface. This study provides direct visualization of SEI evolution in CSPEs and clarifies its role in dendrite-free all-solid-state lithium metal batteries.

Wide-bandgap perovskite solar cells play a key role in tandem solar cells, which aim to overcome the Shockley-Queisser limit for single-junction solar cells. In this work, we develop and optimize a gas quenching method under ambient conditions for the fabrication of wide-bandgap (1.77 eV) perovskite films. To improve the performance of PSCs, three different organic spacer cations, including aromatic amino molecules (PEAI), aliphatic amino with long alkyl chain molecules (OAI), and short alkyl chain molecules (BAI), are applied and investigated as surface passivation materials. As a result, the 2D perovskite layers form on top of the 3D perovskite films. The n-i-p devices with PEAI passivation exhibit the highest photovoltaic performance with a champion power conversion efficiency (PCE) of 16.26% along with a high V_oc of 1.21 V, exceeding the control device (PCE = 13.42%, V_oc = 1.15 V), and maintaining 88% of its initial PCE after 120 min of continuous illumination under a nitrogen atmosphere at room temperature. This work offers a guide for the fabrication of wide-bandgap PSCs under ambient conditions and the choice of organic spacer cations for passivation.