Metal halide perovskite nanocrystals (PNCs) are exceptional light emitters for next-generation display technologies, yet their practical deployment is critically hindered by poor photostability. A long-standing puzzle is the contradictory report of either photodegradation or photobrightening under illumination, suggesting a dynamic competition between these opposing processes; however, the underlying determinant factor remains elusive. Here, we demonstrate that the intrinsic microstructure of PNC films dictates this dynamic competition. We engineer CsPbBr3 PNC films with identical chemical composition yet distinct microstructures (discrete nanoparticles versus sintered networks) as two well-defined initial states. Under continuous-wave illumination relevant to the operational conditions, discrete films undergo progressive photodegradation, whereas sintered films display enhanced photoluminescence. As revealed by systematic spectroscopic, photoelectric, and morphological analyses, the microstructure dictates the competition between photodegradation and photobrightening by determining whether light exposure predominantly creates or passivates trap states. Building on these mechanistic insights, we develop a sequential thermal annealing-light exposure strategy yielding close-packed PNC films with unprecedented photostability, showing less than 1% photoluminescence fluctuation under intense irradiation in air. This work establishes the microstructure as the decisive factor controlling the competition between photodegradation and self-healing, providing a fundamental mechanistic framework and a practical engineering pathway toward stable PNC-based color conversion layers for high-power light-emitting applications.

To address the growing demand for advanced oil-control materials in cosmetics, this study developed novel flower-like mesoporous silica nanoparticles (FLS) with topology-enhanced oil-adsorption properties. Using a biphasic microemulsion synthesis strategy, FLS with petal-like surface topology, radial pore channels, and excellent colloidal stability were successfully prepared. Compared with conventional mesoporous silica nanoparticles (MSN) with small mesopores (2-3 nm) synthesized via the classical Stöber method, FLS exhibited significantly superior oil-absorption capacity across a wide range of oils, with maximum uptake nearly twice that of MSN. Notably, FLS showed exceptional adsorption efficiency for large-molecular-weight oils, demonstrating an approximately 226.3% increase over MSN in adsorbing PDMS-15000 w. This remarkable enhancement is attributed to the unique flower-like topology, which provides large open concave structures for instantaneous oil wetting and straight, radially aligned mesochannels for rapid oil transport and maximized pore utilization. In vivo human skin tests further confirmed the cosmetic efficacy of FLS. Collectively, these findings position FLS as a next-generation oil-control material and highlight topology-enhanced oil adsorption as a novel design strategy for advanced adsorbents.

Precursor additives are crucial for enhancing the efficiency and stability of perovskite solar cells. However, their traditional selection of additives primarily relies on empirical trial-and-error approaches, which are time-consuming and inefficient. Herein, we utilize Perovskite-R1, a large language model, to rapidly identify an efficient additive: ethyl 2-aminopropanoate hydrochloride (EAH). This additive simultaneously passivates defects and regulates crystallization through the coordination of its -CO and -NH3 + groups with the uncoordinated Pb2+ and I- ions in the perovskite. These interactions significantly improve charge-carrier transport and suppress nonradiative recombination, leading to a champion power conversion efficiency (PCE) of 22.58%. Furthermore, the EAH-modified device exhibits excellent long-term stability, maintaining 95.1% and 94.1% of its initial PCE after 1368 h of storage in N2 and 1272 h of thermal aging at 65°C, respectively. This study highlights the potential of integrating artificial intelligence with materials design to accelerate the discovery of high-performance, stable, and sustainable perovskite optoelectronic materials.

Synthesizing high-nickel single-crystal layered oxide cathodes via high-temperature solid-state lithiation is plagued by Ni3+ thermal instability and inefficient solid-solid mass transfer, which induce severe structural defects and hinder grain boundary fusion. Herein, we propose a dual-stage pre-lithiation strategy coupled with microchannel-synthesized nano-sized Ni0.9Co0.05Mn0.05(OH)2 precursors, targeting low-defectivity, highly structurally stable single-crystal LiNi0.9Co0.05Mn0.05O2 cathodes. These precursors enhance lithium salt accessibility, create abundant active sites, and shorten Li+/O2-diffusion pathways, laying a structural foundation for homogeneous topological lithiation. Furthermore, the optimized dual-stage pre-lithiation process enables regulation of disordered rock-salt and layered lithiation intermediates. A tailored amount of rock-salt intermediates retards layered ordering kinetics, synchronizing single-crystal growth with layered structure formation during lithiation, whereas premature layered formation induces Ni2+ migration and Li/O loss, triggering structural defects. XRD and HRTEM characterizations confirm the SC90-200&500 cathode exhibits low structural defects and a well-defined layered single-crystal structure, achieving 56.6% capacity retention at 0.5C after 200 cycles and a thermal runaway temperature of 235.1 degrees C. This intermediate-phase regulation strategy, serving as a structural buffer and leveraging nano-sized precursors to mitigate solid-state mass transfer barriers, offers a scalable framework for balancing lithiation kinetics and structural stability in high-nickel single-crystal layered oxide cathodes synthesis, thus addressing the core challenge of defect control in solid-state lithiation.

Highly dispersed tetragonal phase BaTiO3 nanoparticles were synthesized via a hydrothermal method. The effects of TiO2 precursor and hydrothermal media on the phase transformation and microstructure of BaTiO3 nanocrystals were investigated. Additionally, the time-dependent evolution of nucleation and crystal growth was elucidated. A key influencing factor of this method is the use of a well-crystallized TiO2 as the precursor, combined with ammonia-based reaction media; this combination not only promotes nucleation but also inhibits OH defect formation during crystal growth. Consequently, superior tetragonality and narrow particle size distribution of BaTiO3 nanoparticles can be achieved. Furthermore, atomic-scale internal and surface structure were investigated using high-angle annular dark field scanning transmission electron microscopy. Ferroelectric and piezoelectric properties of the prepared samples were examined based on their polarization characteristics using piezoelectric responsive force microscopy, further confirming the high tetragonality of the as-prepared BaTiO3 nanoparticles.

Abstract Suppressing nonradiative multiexciton Auger recombination in lead halide perovskite quantum dots (PQDs) remains a critical challenge for their application in high-power optoelectronic devices. Here, we demonstrate that a quasi-type II band alignment can be constructed by feasibly coating CsPbBr3 PQDs with CdS to form a tailored heterostructure, whereby the multiexciton Auger recombination can be effectively mitigated. Steady-state and time-resolved spectroscopic results reveal a prolonged exciton lifetime along with a moderate reduction in photoluminescence quantum yield, suggesting decreased electron–hole wave function overlap. Using selective charge scavengers, we show that holes remain confined within the perovskite core while electrons delocalize across the entire nanocrystal, in excellent agreement with the quasi-type II band configuration. As further revealed by transient absorption spectroscopy, such band alignment engineering increases the Auger recombination lifetime from 48 ps in the pristine PQDs to 220 ps in the CdS-coated PQDs. This work demonstrates an effective strategy to suppress Auger recombination in PQDs and provides a mechanistic framework of material design with tailored carrier dynamics for high-fluence optoelectronic applications.

The introduction of self-assembled molecular layers (SAMs) has recently brought breakthroughs to inverted perovskite solar cells (PSCs). Among them, the NiOx/Me-4PACz hole transport layer (HTL) system exhibits remarkable potential for enhancing device performance. However, Me-4PACz suffers from inherent limitations, including uneven distribution, poor wettability with perovskite solution and limited stability. In this study, we introduce metformin hydrochloride (MFCl) and triaminoguanidine hydrochloride (TGCl) as internal molecular "bridges" between NiOx and Me-4PACz to address these issues. This strategy aims to enhance charge transport, strengthen the interfacial anchoring between NiOx and Me-4PACz, regulate the molecular organization of Me-4PACz, and optimize the buried interface. As a result, the crystallinity and quality of the perovskite layer are significantly improved, leading to enhanced device performance. The power conversion efficiency (PCE) of the modified device increases notably from 20.45% to 23.11% (MFCl) and 23.06% (TGCl), along with substantial improvements in operational stability.

The synthesis methods of SnO2 electron transport layer critically determine the performance of the perovskite solar cells (PSCs), as it governs the particle size, crystallinity, dispersibility, and surface chemistry. In this study, we systematically investigated how the pH (acidic, neutral, or alkaline) during the synthesis of SnO2 affects the efficiency and stability of PSCs. The acidic-derived SnO2 (AC-SnO2) features a carboxyl-rich surface that promotes strong hydrogen bonding with FA+ cations but also accelerates iodide (I-) oxidation. In contrast, the alkaline-derived SnO2 (AL-SnO2) contains a high density of oxygen vacancies, which facilitate the decomposition of the perovskite into Pbl2. Notably, the neutral-synthesized SnO2 (N-SnO2) provides optimal interface properties, yielding a champion active-area efficiency of 26.10% for small-area cells (0.09 cm2) and 23.10% for mini-modules (14 cm2). This work highlights the central role of synthesis pH in tailoring interfacial chemistry and achieving high-performance, stable PSCs.

Perovskite quantum dots (PQDs) feature exceptional single-photon upconversion (SPUC) photoluminescence, rendering them promising candidates for use in optical refrigeration. Despite significant advancements in recent fundamental studies, the specific scenario of uphill carrier activation involved in the SPUC process has not been fully elucidated. Herein, the mechanism of SPUC in PQDs, with particular attention paid to the underlying carrier-transition kinetics, is systematically investigated through time- and energy-resolved spectroscopic techniques. Quantitative analysis results indicate a significant deviation of the upconversion behavior from that predicted by the two-level direct-transition model, a simplified theoretical framework commonly applied to PQDs. Conversely, an additional energy barrier ΔE*, superposed on the SPUC energy gap, plays a pivotal role in determining the carrier activation kinetics. We further verify that ΔE* is associated with the intrinsic properties of the perovskite lattice and is barely influenced by the nanocrystal surface chemistry. The presented findings provide a valuable framework for improving the SPUC performance of PQDs from the perspective of lattice regulation, in addition to the widely used ligand engineering approach, paving the way for the rational design of next-generation optical refrigeration materials.

Ion migration is considered a dominant factor responsible for the poor stability of perovskite solar cells (PSCs). Alkali metal doping into the hole transport layer (HTL) has emerged as an effective strategy for regulating ion migration, yet the detailed landscape in PSC devices is still poorly clarified. Here, we systematically investigate the influence of Rb+ doping in NiO x HTLs on ion migration in inverted PSCs using a custom-built circuit-switched transient photoelectric technique (cs-TPT). By decoupling the electronic and ionic contributions to photovoltage output, we provide direct evidence that ion migration can be effectively suppressed with increasing Rb+ concentration. Combining the well-established band alignment regulation of Rb+ doping and the model of polarization-induced trap states, we attribute this suppression to a reduced driving force for ion accumulation at the perovskite/HTL interface. More importantly, the suppressed ion migration occurs independently of the photovoltaic performance, which remains largely unchanged across all tested devices, providing a mechanistic framework for understanding ion migration in inverted PSCs.

Nickel oxide (NiOx) is one of the most widely employed hole transport layers (HTLs) in inverted perovskite solar cells (PSCs) due to its low-temperature processability, compatibility with scalable fabrication, and favorable energy-level alignment. Since 2015, extensive efforts have been devoted to enhancing the optoelectronic properties of NiOx; however, most studies have predominantly focused on planar NiOx (pNiOx) films. In this study, we fabricate a mesoporous nickel oxide (mNiOx) HTL via high-temperature calcination, using nickel nitrate hexahydrate (Ni(NO3)2·6H2O) as the nickel precursor, Pluronic P123 and a small amount of polyvinylpyrrolidone (PVP) as structure-directing templates. The resulting mesoporous framework modulates the perovskite crystallization kinetics, enhances the buried interface, improves the crystallization quality, reduces the defect density, and shifts the interfacial stress state from tensile to compressive. Consequently, both the open-circuit voltage (VOC) and fill factor (FF) of the devices are significantly enhanced. The PSCs based on the mNiOx HTL achieve a power conversion efficiency (PCE) of 23.19%, along with markedly improved operation and storage stability.

Understanding how the primary particle structure governs lithiation reconstruction and single-crystal formation in ultrahigh-nickel cathodes is crucial for simultaneously achieving high energy density and structural durability. However, this intrinsic relationship remains difficult to resolve in conventional micron-sized precursor systems because transport limitations and reaction heterogeneity are often intertwined during thermal reconstruction. Herein, uniform nanosized Ni0.92Co0.04Mn0.04(OH)2 precursors synthesized by microchannel coprecipitation were employed as a model system to isolate the role of primary particle structural characteristics. Sulfate- and acetate-based coprecipitation systems were employed to fabricate precursors with differentiated primary particle structures in particle size and crystallographic orientation. It is demonstrated that the primary particle structures favorable for single-crystal formation cannot merely accelerate the lithiation process but, more importantly, enable superior synchronization between lithiation kinetics and structural ordering throughout the calcination process. Such structural characteristics promote intergranular fusion and efficient grain-boundary elimination, leading to a highly integrated single-crystal LiNi0.92Co0.04Mn0.04O2 (NCM92) cathode with low Li/Ni disorder (2.1%), fewer oxygen vacancies, and superior structural integrity. By contrast, precursor structures with smaller particles and less coherent crystallographic organization undergo rapid initial lithiation but tend to produce incomplete crystallographic fusion, resulting in quasi-single-crystal products with residual grain boundaries and higher defect concentrations. Consequently, the optimized cathode exhibits markedly improved electrochemical and thermal stability. This work reveals that the key to robust single-crystal formation lies in effectively coupling lithiation reactivity with crystal ordering and establishes a structure-guided framework for the rational design of durable ultrahigh-nickel cathodes.

Carbazole-based passivators effectively mitigate defects in perovskite films, thereby enhancing both the efficiency and operational stability of the derived devices. The defect passivation efficacy and hole extraction capability are governed by the molecular structure, encompassing the central carbazole core and the functional side chains. However, a deeper mechanistic understanding of the structure-property relationship is essential to further optimize their passivation performance. To overcome these challenges, we introduce two distinct carbazole-based multifunctional passivation molecules for interfacial modification. The results reveal that the carbazole passivators not only effectively suppress interfacial defects but also facilitate hole extraction owing to the intrinsic hole-transporting properties of the carbazole moiety. Consequently, the optimized perovskite device based on N, N, N', N'-tetra(4-methoxyphenyl)-9H-carbazole-3,6-diamine (4NDMCz) delivers a remarkable power conversion efficiency (PCE) of 25.56% for a small-area device (0.09 cm2) and 21.23% for a mini-module (23.4 cm2). Moreover, the devices retain over 90% of their initial efficiency after 1000 h of continuous operation under maximum power point (MPP) tracking, demonstrating excellent long-term operational stability. This work provides valuable insights into interfacial passivation strategies for the development of efficient and stable perovskite devices.

Abstract The small ionic radius of Cs+ results in a low tolerance factor for CsPbI3 perovskite, which intrinsically triggers its spontaneous phase transition from black phase to yellow phase, severely limiting the power conversion efficiency and long-term stability of CsPbI3 perovskite solar cells. Here, we propose an in situ surface reconstruction strategy by introducing formamidinium ions (FA+) onto the CsPbI3 perovskite surface during the spin-coating process. This approach locally increases the tolerance factor in the near-surface region without altering the bulk phase, thereby raising the energy barrier for phase transition and substantially improving phase stability. Furthermore, the incorporation of FA+ boosts the perovskite crystalline quality, reduces defect density, and optimizes interface energy-level alignment. Consequently, the corresponding devices exhibit an improvement in photovoltaic performance alongside significantly enhanced stability under various harsh conditions.

CsPbI3 perovskite has emerged as a promising material for photovoltaic applications owing to its thermal stability and near-ideal bandgap. However, its tendency to transition from photoactive black phase to yellow phase and the processing-induced defects pose significant challenges to its photovoltaic performance. In this study, we propose an innovative in situ polymerization strategy to overcome these limitations by incorporating a multifunctional polymer into CsPbI3 perovskite films. Specifically, 2,2,3,4,4,4-hexafluorobutyl acrylate monomers are employed to modify the perovskite film surface, where they undergo in situ polymerization during thermal annealing to form an integrated protective network. The resulting polymer modifier exhibits multiple synergistic functions: the carbonyl groups passivate undercoordinated Pb2+ defects and the -CFH- groups interact with I- species to suppress ion migration, while the hydrophobic fluorinated chains enhance moisture resistance. Furthermore, the existence of the polymer could increase the steric hindrance of octahedral distortion to enhance the stability of black-phase CsPbI3. Notably, the polymer-modified perovskite exhibits improved film quality with reduced defects, which facilitates efficient charge transport and extraction. As a result, the optimized CsPbI3 perovskite solar cells achieve a power conversion efficiency of 15.23%, along with substantially improved storage stability. Meanwhile, this polymer-modification strategy effectively mitigates lead leakage, providing a valuable route toward more environmentally friendly CsPbI3 perovskite solar cells.

IN738LC has been widely used in hot-end components owing to its excellent high-temperature performance, while it has still suffered from metallurgical defects during laser powder bed fusion (LPBF) due to its high crack sensitivity. This study investigated forming behavior, microstructure evolution and mechanical property of LPBFprocessed IN738LC samples at different parameters (laser power of 150-300 W, scanning speed of 500-1500 mm/s). The result indicated that the decrease in energy density caused the width and depth of the melt pool to decrease and eventually broke into droplets, leading to an increase in porosity. As the scanning speed increases, the microstructure changes from irregular columnar/cellular dendrites to all distributed as columnar dendrites, exhibiting epitaxial growth. An optimal process window was finally obtained at a laser power of 200 W and a scanning speed of 1000 mm/s, which achieved excellent forming quality (the porosity of 0.01 %) and mechanical properties (microhardness of 445.5 HV, ultimate tensile strength of 1335 MPa and elongation of 19.3 %). This study provides process basis for subsequent studies of IN738LC fabricated by LPBF.

Lithium-ion batteries (LiBs) are pivotal for applications in electric vehicles, portable electronics, and energy storage systems, owing to their high energy density and long cycle life. Nevertheless, the intrinsically low electronic conductivity of Ni-rich cathodes (e.g., NCM811) severely restricts charge transfer kinetics, thereby constraining battery performance. To address this critical issue, a composite conductive additive comprising functionalized carbon nanotubes (CNTs) and carbon black (CB) is designed to construct a 3D conductive network and facilitate lithium-ion transport. Furthermore, the regulatory effects of CNTs' functionalized groups (& horbar;COOH, & horbar;OH, & horbar;NH2) on cathode-electrolyte interface (CEI) formation kinetics, cathode structural stability, and long-term cycling performance are elucidated. The results reveal that the steric hindrance and polarity of functional groups significantly influence both the construction of the conductive network and the formation and stability of the CEI layer. Among them, the optimized CB/CNT-COOH electrode exhibits superior rate capability (53.1% capacity retention at 10C relative to 0.1C) and cycling stability (73.8% retention after 200 cycles at 1C), surpassing pristine CB and other functionalized CNTs. This work clarifies the mechanism of functional groups optimizing charge transport and interfacial stability, providing a scalable strategy to advance high-energy Ni-rich cathodes.

Organic-inorganic hybrid perovskites have demonstrated great potential for flexible optoelectronic devices due to their superior optoelectronic properties and structural flexibility. However, mechanical deformation-induced cracks at the buried interface and delamination from the substrate severely constrain the optoelectronic performance and device lifespan. Here, we design a two-site bonding strategy aiming to reinforce the mechanical stability of the SnO2/perovskite interface and perovskite layer using a multifunctional organic salt, 4-(trifluoromethoxy)phenylhydrazine hydrochloride (TPH). This approach significantly enhances the bonding at the buried interface between the electron transport layer and perovskite layer, which is demonstrated by TPH-modified SnO2/perovskite interface remaining intact after 10,000 bending cycles. Meanwhile, TPH mitigates void formation, enhances perovskite crystallinity at the buried interface, and inhibits ion migration inside the devices. Furthermore, incorporating TPH in perovskite bulk decreases the nucleation activation energy and accelerates nucleation, leading to high-quality perovskite film. Consequently, power conversion efficiencies (PCEs) of 21.64 % and 23.61 % are achieved for target flexible and rigid perovskite solar cells, respectively. The target flexible device retained 92.3 % of its initial PCE after 25,000 bending cycles. This approach provides a robust solution for enhancing the mechanical durability of flexible perovskite optoelectronic devices.

Cesium lead iodide perovskite (CsPbI3) is a class of promising photovoltaic materials while prone to undergo spontaneous transformation from the photoactive black phase to the nonphotoactive yellow phase under ambient conditions, posing a significant challenge to the long-term applications. Herein, a buried interface regulation strategy is reported, where the crystalline seeds containing bromide ions are formed on the substrates through a treatment with cesium bromide prior to the growth of CsPbI3. This results in the initial construction of a thin CsPbI3-xBrx perovskite layer with high lattice matching at the buried interface, which enables the subsequent growth of highly oriented CsPbI3 perovskites that effectively enhances their phase stability. Furthermore, the modified substrate reveals greater wettability, leading to accelerated crystallization kinetics, reduced defect density, and favorable interfacial charge transfer. Consequently, the corresponding device exhibits simultaneous promotion in both photoelectric performance and operational stability.