Key Takeaways & Executive Findings
- •• • Nano-GT depth reduction from 15.3 nm to 4.4 nm via BAAc pre-incorporation directly correlates with elimination of grain-to-grain CL emission heterogeneity, establishing a nanoscale morphological threshold for cation homogenization. • • Pristine FA-Cs perovskite films exhibit distinct CL emissions at grain boundaries, confirming that cation inhomogeneity is localized to GB grooves; shallowed nano-GTs yield uniform CL maps, validating cross-grain compositional uniformity. • • Thermodynamics-driven GB grooving merges at triple junctions to form trap-like nanostructures that impede cation mixing; BAAc enhances heterointerface energy to suppress groove depth, offering a scalable chemical route for morphological control. • • The 71% reduction in nano-GT depth (15.3 nm to 4.4 nm) provides a quantifiable process target for industrial perovskite deposition, potentially extending PSC operational stability by mitigating phase segregation pathways.
China Clean Energy & Battery Radar
Get verified English translations, SEM micrographs & open-access PDF alerts from China's leading state key laboratories delivered to your inbox every Monday at 08:00 EST.
Abstract
Cation segregation in formamidinium-cesium (FA-Cs) mixed-cation perovskites remains a critical barrier to the long-term operational stability of perovskite solar cells (PSCs). While compositional and microstructural engineering has advanced power conversion efficiencies (PCEs), grain-to-grain cation inhomogeneity at the nanoscale persists, compromising device durability. This analysis examines recent work by Zhou's group, which establishes a direct correlation between cross-grain cation homogenization and the thermodynamics-driven morphologic grooving of as-formed grain boundaries (GBs). These grooves merge at triple junctions to form nanoscale groove traps (nano-GTs) that impede cation mixing. By pre-incorporating butylammonium acetate (BAAc), the average nano-GT depth was reduced from 15.3 nm to 4.4 nm, driven by enhanced heterointerface energy. High-resolution atomic force microscopy (AFM) confirmed shallower nano-GT geometries, while cathodoluminescence (CL) hyperspectral mapping revealed that pristine samples exhibit distinct CL emissions across grains due to FA-Cs inhomogeneity. In contrast, shallowed nano-GT films show no discernible CL emission variation among grains, indicating homogeneous cation distribution. These findings provide a quantitative morphological lever for suppressing phase segregation and enhancing the operational longevity of perovskite-based devices.
1. Introduction
Commercial deployment of formamidinium lead triiodide (FAPbI3) perovskite solar cells has been stalled by intrinsic phase instability and cation segregation, particularly in cesium-incorporated mixed-cation systems. While FA-Cs perovskites stabilize the photoactive black phase, uneven Cs distribution across grains creates nanoscale compositional heterogeneity that accelerates degradation and compromises power conversion efficiency (PCE). Existing mitigation strategies have addressed out-of-plane and in-plane inhomogeneities at the film scale, yet grain-to-grain cation variations at the nanoscale remain unresolved, leaving a critical gap in the pathway to durable devices.
Zhou's group demonstrates that cross-grain cation homogenization is governed by the thermodynamics-driven morphologic grooving of grain boundaries (GBs). These grooves merge at triple junctions to form nanoscale groove traps (nano-GTs) that physically impede cation mixing. By pre-incorporating butylammonium acetate (BAAc), the average nano-GT depth was reduced from 15.3 nm to 4.4 nm through enhanced heterointerface energy. Cathodoluminescence (CL) hyperspectral mapping confirmed that shallowed nano-GTs eliminate discernible grain-to-grain CL emission variations, directly linking nanoscale morphology to cation uniformity. This protocol offers a precise morphological lever for suppressing phase segregation and advancing the operational stability of perovskite photovoltaics.
Loading authentic research manuscript (Pages 1–5)...
Jingbi You (2025). Resolving Nano-Morphologies: A Pathway to Cross-Grain Homogeneous Cation Distribution in Perovskites. SCIENCE CHINA Materials. https://doi.org/10.1007/s40843-025-3343-0
Research & Educational Purpose Only: The translations, structured abstracts, analytical annotations, and data reports provided by SinoGreenTechare intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoGreenTech claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the exact failure mechanism linking nano-GT depth to cation segregation in FA-Cs perovskites?
Thermodynamics-driven GB grooving creates nano-GTs that merge at triple junctions, forming trap-like nanostructures. These structures segment the film surface and physically impede cation mixing, resulting in grain-to-grain FA-Cs inhomogeneity. Pristine films exhibit distinct CL emissions at GBs, confirming that deeper nano-GTs (15.3 nm average) correlate with compositional discontinuities.
How does BAAc pre-incorporation achieve a 71% reduction in nano-GT depth, and what is the quantitative evidence?
BAAc enhances heterointerface energy, driving the formation of shallowed nano-GT perovskite films. High-resolution AFM shows the average nano-GT depth decreases from 15.3 nm to 4.4 nm. This 71% reduction is directly linked to flattened groove geometry and eliminated CL emission heterogeneity among grains.
What is the industrial scalability risk of using BAAc to control nano-GT depth in large-area perovskite deposition?
The protocol relies on precise pre-incorporation of BAAc to modulate interfacial energy during film formation. Scalability requires uniform BAAc distribution across square-meter substrates; any concentration gradient could reintroduce nano-GT depth variability. Process control must maintain depth below 5 nm to ensure cross-grain cation homogeneity, as demonstrated by the 4.4 nm average.
Does the elimination of CL emission heterogeneity directly translate to improved PCE and operational stability?
The study establishes a direct correlation between shallowed nano-GTs (4.4 nm) and uniform CL maps, indicating homogeneous FA-Cs distribution. This homogeneity is essential for suppressing phase segregation, which is a primary degradation pathway. While PCE values are not reported in the extracted text, the morphological threshold provides a quantifiable target for stabilizing PSCs.
What are the limitations of CL hyperspectral mapping for quantifying grain-to-grain cation distribution in commercial perovskite films?
CL mapping reveals relative emission variations but does not provide absolute cation concentrations. The technique requires high-resolution SEM integration and is sensitive to surface recombination. For industrial quality control, complementary techniques such as atom probe tomography or nano-SIMS would be necessary to validate cross-grain homogeneity at the 4.4 nm nano-GT depth threshold.
Related Chinese Research & Cross-Citations
Ammonium Vanadate Cathodes in Aqueous Zinc-Ion Batteries: Design Strategies and Research Progress
Aqueous zinc-ion batteries (AZIBs) offer a compelling combination of high safety, environmental compatibility, and abundant zinc resources, positioning them as viable candidates for grid-scale energy storage. Their practical deployment, however, is constrained by cathode materials that suffer from structural degradation, sluggish Zn2+ diffusion, and inadequate electronic conductivity. Ammonium vanadates (AVOs) have emerged as high-performance cathodes owing to their layered or tunneled frameworks, which accommodate reversible Zn2+ (de)intercalation with diffusion coefficients superior to conventional vanadium oxides. This review systematically examines recent advances in AVO cathodes for AZIBs, correlating morphological variations—including nanowires, nanobelts, and microflowers—with electrochemical characteristics. The analysis establishes structure–performance relationships that govern capacity retention, rate capability, and cycling stability. Key optimization strategies are critically assessed: defect engineering to enhance electronic conductivity and active site density, interlayer spacing modulation via pre-intercalated cations or structural water to facilitate Zn2+ transport, and composite construction with conductive carbonaceous or polymeric matrices to mitigate dissolution and improve mechanical integrity. Despite these advances, challenges persist in achieving long-term cycling stability (>10,000 cycles) and high areal mass loading (>10 mg cm-2) required for commercial viability. The review concludes by outlining future research directions, including operando characterization of degradation mechanisms and scalable synthesis routes for AVO cathodes in practical AZIB configurations.
Microenvironment-responsive therapeutic platforms: Innovations for spinal cord injury repair
Spinal cord injury (SCI) remains a formidable clinical challenge due to the complex, dynamic lesion microenvironment that impedes axonal regeneration and functional recovery. This highlight examines a microenvironment-responsive therapeutic platform integrating microneedle delivery, ferroptosis modulation, and hydrogen therapy. The platform leverages the pathological hallmarks of SCI—oxidative stress, iron dyshomeostasis, and lipid peroxidation—to achieve spatiotemporally controlled cargo release. By combining microneedle arrays for minimally invasive intraparenchymal administration with hydrogen-releasing biomaterials, the system addresses the dual bottlenecks of poor drug penetration across the blood-spinal cord barrier and insufficient neutralization of reactive oxygen species. Ferroptosis inhibition is achieved through iron chelation and glutathione peroxidase 4 (GPX4) stabilization, while hydrogen gas scavenges hydroxyl radicals and peroxynitrite. This multimodal strategy attenuates secondary injury cascades, reduces glial scar formation, and promotes neural stem cell differentiation. The work is supported by the National Natural Science Foundation of China (82574518) and the Talent Cultivation Project of Paring Academicians with Young Talents in higher education institutions in Zhejiang. The authors declare no conflict of interest. This highlight underscores the translational potential of microenvironment-responsive platforms for SCI repair, emphasizing the need for rigorous preclinical validation and scalable manufacturing.
Dual-Site Adsorption over Phosphorus-Doped Copper Oxide for Efficient CO2 Electroreduction to Ethylene
Electroreduction of CO2 to ethylene offers a promising route for renewable electricity storage, yet achieving high ethylene selectivity at industrial current densities remains challenging due to the large energy barrier for C–C coupling. Here, we report a “MOF-assisted in situ doping” strategy to introduce the oxophilic nonmetal phosphorus (P) into the copper oxide (CuO) lattice, constructing a localized Cu–P dual-site adsorption configuration for the key *OCCHO intermediate. The optimized catalyst delivers an impressive Faradaic efficiency of 64.6% for ethylene with a partial current density of 646 mA cm-2. Comprehensive structural characterizations demonstrate that P mainly occupies Cu sites, generating abundant lattice defects and oxygen vacancies. In situ synchrotron infrared spectroscopy and theoretical calculations reveal that P doping modulates the electronic structure of Cu, optimizes the binding energies of *CO and *CHO, and stabilizes *OCCHO via P–O/Cu–C dual-site adsorption, thereby significantly lowering the asymmetric C-C coupling energy barrier to 0.74 eV. This work highlights a dual-site microenvironment regulation strategy for CO2-to-ethylene electroreduction.
Hydrophilic Single-Atom Interface Unlocks Low-Potential CO Removal on Pt in PEMFCs
Proton exchange membrane fuel cells (PEMFCs) fed with reformate hydrogen suffer severe anode poisoning by trace CO, necessitating high CO electrooxidation potentials that degrade performance and durability. This work introduces a Pt@CrSA-N-C anode catalyst featuring a hydrophilic Cr single-atom interface that simultaneously weakens CO adsorption on Pt via electronic regulation and promotes water activation, thereby lowering the CO oxidation onset potential to approximately 0.13 V vs. RHE. The onset potential was determined by two independent methods: the first potential at which the background-corrected current exceeds 0 mA cm-2 during CO oxidation reaction tests in a three-electrode system, and the potential at which the forward scan current exceeds the N2 background current in CO-stripping voltammetry. The catalyst achieves a maximum power density under 100 ppm CO that surpasses reported advanced catalysts, as compiled in Table S5. Structural, spectroscopic, and electrochemical characterizations collectively establish a coherent rationale for the hydrophilic single-atom interface strategy. This approach addresses the longstanding trade-off between CO tolerance and Pt utilization, offering a viable route for low-potential CO removal in practical PEMFC anodes.
An Ionoelastomer-Based Bioinspired Wearable Electronics with Tele-Perception and Tactile Sensation for Machine Learning-Assisted Rehabilitation Management
Comprehensive assessment of rehabilitation efficiency is essential for designing appropriate training programs for better musculoskeletal functional recovery. Existing contact-receptor-dependent rehabilitation assessment systems mostly focus on assessing the restoration of muscle function by evaluating grip strength or joint flexion angle; however, parameters reflecting neuromuscular synergistic function are always overlooked. Herein, we develop an ionoelastomer-based soft artificial electroreceptor (SAER) that integrates tele-perception and tactile sensation to track the rehabilitation process, collecting signals related to approaching speed and grip strength sequentially. The SAER uses polyurethane ionoelastomer incorporated with quasi-solid conductive salt as the electric field receptor, and is integrated on a rehabilitation-training ball after assembly to establish an untethered detection device; this enables the remote capture of hand approaching parameter within a 9 cm range, followed by the quantification of grip strength when contacting and grasping. Furthermore, a data-driven assessment system is established by integrating machine learning, which accurately classifies rehabilitation efficiency into six levels; it supports for rehabilitation evaluation and training programs adjustment. Overall, the SAER-based rehabilitation management system establishes a paradigm that synergistically evaluating parameters corresponding to neuromuscular functional restoration and holds strong potential for home-based active rehabilitation for minimizing dependence on frequent clinical supervision.
Microwave-Absorbing Materials with Strong Environmental Adaptability for Corrosion Protection, Anti-Icing, and Thermal Management
Microwave-absorbing materials (MAMs) deployed on naval vessels, aerospace vehicles, and critical electronic systems face coupled electromagnetic, marine salt-spray corrosion, and extreme-temperature loads that legacy single-function absorbers cannot withstand. This review consolidates progress on three environmentally adaptive MAM classes: corrosion-protective, anti-icing, and thermal-management absorbers. The electromagnetic loss and impedance-matching fundamentals are first established, then the synergistic mechanisms, design strategies, and characterization protocols for each class are examined against representative material systems and their measured performance. The analysis identifies a shared design logic—multiscale hierarchical architecture, interfacial polarization engineering, and multifunctional phase integration—while distinguishing the divergent protection mechanisms: barrier and passivation effects for corrosion, surface-energy and latent-heat regulation for anti-icing, and phonon–electron transport decoupling for thermal management. Persistent bottlenecks include the trade-off between impedance matching and protective-layer density, the absence of standardized coupled-field test protocols, and the scarcity of long-term salt-spray and thermal-cycling durability data. Future directions are delineated: intelligent self-adaptive absorbers, multiphysics-coupled simulation frameworks, and environmentally benign multifunctional integration. The review provides a theoretical and technical basis for the design, construction, and engineering scale-up of next-generation high-performance absorbers for aerospace, electronic, and marine equipment.