Compared to ABO3 oxide perovskites, intrinsic ferroelectricity is less studied in ABX3 (X = Cl, Br, I) halide perovskites. Nonetheless, it presents unique opportunities, such as achieving ferroelectric photovoltaics with band gaps suitable for the solar spectrum. In this work, we focus on the CsGeX3 halide perovskites as prototypes for investigating the origin of their ferroelectricity and its relationship with other properties. We find that the presence of stereochemically lone pairs on the perovskite B-site is the primary driving force for ferroelectricity, causing off-center displacements of the Ge ions and enhanced covalency with the halide ligands. This contrasts with the behavior of typical ferroelectric oxide perovskites. Our calculations confirm that halide perovskites are intrinsic modest band gap semiconductors. In particular, CsGeI3 exhibits a very favorable band gap of 1.6 eV for photovoltaic applications. Our findings provide valuable insights into the mechanism underlying high-temperature ferroelectricity in halide perovskites with potential optoelectronic applications.

Surface plasmon resonance (SPR) sensors on fiber end-facets have been paid much attention due to the ultrahigh quality factor (Q) and the figure of merit (FOM), but their scalable and low-cost fabrication remains challenging. Herein, we present a high-efficiency, reproducible fabrication method using a silicon template transfer technique to realize high-performance SPR microcavities with nanoslit-arrays on single-mode fiber end-facets. Benefiting from mature silicon-based lithography and dry etching techniques, the nanoslit-arrays with nearly vertical sidewalls are fabricated sophisticatedly, which effectively suppress radiation loss while improving resonance Q. The fabricated sensor shows a refractive index sensitivity of 532 nm/RIU, an experimental Q-factor of 142, and a FOM of 91 RIU-1, representing a similar to 40% performance improvement over conventional direct metal patterning. We further implement label-free biosensing experiments to validate the practical performance of the optimized devices, including dynamic real-time monitoring of bovine serum albumin (BSA) physical adsorption with concentration gradients from 100 ng mL-1-10 & micro;g mL-1. The biosensing results exhibit an ultralow peak-to-peak wavelength shift noise of 2 pm and a sensitive response to trace biomolecular adsorption. The proposed silicon-template stripping transfer method also enables reproducible fabrication to improve manufacturing efficiency and reduce production cost. (c) 2026 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.

Fiber-optic temperature sensors that use surface plasmon resonance (SPR) sensing structures combine the flexibility and compactness of optical fibers with the high sensitivity of the SPR evanescent field. Compared with the traditional geometry-in which the SPR sensing structure is distributed along the fiber sidewall or fills the inner space of the fiber-constructing SPR sensing structures on the tip of a fiber has unique advantages for investigating extremely small objects with minimal invasion. Here we report the mounting of an SPR microcavity on the end facet of a single-mode fiber to create a miniature temperature sensor. The SPR microcavity is coated with a temperature-sensitive thin film made from polydimethylsiloxane. The 3 x root-mean-square noise equivalent temperature of this device is similar to 0.02 degrees C; over a 105-minute-long heating and cooling cycle, without any external feedback control, its repeatability was found to be within +/- 0.3 degrees C. The response time of the device was found to be as short as within two seconds. The combination of sensitive detection, stable performance, and fast response, along with the fiber-optic configuration and miniature probe size, makes our device a promising candidate for temperature-sensing applications in biomedicine, industrial production, and environmental monitoring.

This study successfully applies scanning capacitance microscopy (SCM) to organic-inorganic metal halide perovskite materials, providing detailed insights into the microscopic distribution of carrier concentrations and types. We developed and optimized an alumina (Al2O3) insulating layer using atomic layer deposition, with a 5 nm thickness at 398.15 K proving optimal for minimizing defects at the Al2O3/perovskite interface. Further optimizations included selecting an appropriate probe for high-contrast SCM imaging, reducing stray capacitance by scanning at sample edges, and analyzing the effects of light illumination. Our results show that perovskite films with excess PbI2 in the precursor had a more uniform carrier distribution and higher overall carrier concentration. Additionally, we identified distinct p-type and n-type regions in perovskite materials modified with polar molecular additives. This work enables SCM as a robust technique for investigating complex carrier behaviors in perovskite materials.

The synthesis of Li-and Mn-rich layered oxides is often hindered by the formation of a disordered rock-salt-type phase, which is believed to have a negative impact on their electrochemical performance due to the inherently low electrochemical activity of this phase. Herein, we employ a two-step approach involving spray pyrolysis followed by calcination to prepare Co-free Li[Li0.2Ni0.2Mn0.6]O2 (LLNMO) oxides. The disordered Li-containing rock-salt-type phase emerges on the surface of LLNMO crystallites at elevated heating temperatures (>= 930 degrees C). The formation kinetics of the Li-containing rock-salt-type phase is determined to follow a reaction-diffusion process. For LLNMO-950 (950 degrees C) with a coherent structure comprising both layered and thicker Li-containing rock-salt-type phases, the discharge capacity exhibits a progressive increase within the initial 52 cycles. The lattice parameters of the rock-salt structure undergo variations during electrochemical cycling, indicating that the rock-salt-type phase is not completely electrochemically inactive. By adjusting the heating temperature (930 degrees C, denoted as LLNMO-930), we introduce a thin disordered Li-containing rock-salt-type phase (approximately 2 nm thick) on the primary particle surface of LLNMO. The LLNMO-930 exhibits good electrochemical performance, with a high energy density retention of 95 % and a voltage decay of 0.3 V after 100 cycles at 0.1 C.

Achieving stable and reproducible performance has been a major challenge for nanophotonic biosensors. Literature surveys suggest that this instability strongly correlates with the nanostructured physical sensing interfaces, which we tentatively attribute to artifacts like surface gas nanobubbles. Here, we propose the hybridization of surface plasmon polaritons and a metal-insulator-metal waveguide to create a meta-film combining the flat biosensing interface characteristic of SPR with the high surface sensitivity typical of LSPR. This meta-film offers a promising solution for sealing photonic nanostructures under a flat and stable biosensing interface. We embedded the meta-film with a plasmonic crystal cavity and mounted it on a single-mode fiber’s end-facet. This device demonstrated highly stable biosensing performance, achieving convincing results for biotinylated proteins down to 30 fM, with kinetics following the Langmuir model. Possessing both high sensitivity and stability, our approach provides a comprehensive solution for fiber-tip plasmonic biosensing, which is valuable for biomolecular interaction analysis and drug discovery.

Passivating contact solar cells have gradually become the mainstream cell technology due to their excellent performance, and further improving the conversion efficiency has become a focus of subsequent research. Typically, achieving excellent field-effect passivation and low contact resistivity in doped polycrystalline silicon (poly-Si) requires heavy phosphorus doping. However, this approach can lead to a predicament wherein excessive phosphorus diffuses into the silicon (Si) substrate during annealing, consequently causing recombination losses. In response to this challenge, a structure incorporating an intrinsic amorphous silicon (a-Si (i)) layer within the passivation layers has been introduced. The primary objective of this structure is to retard the diffusion of phosphorus into the Si substrate. This study entails comprehensive characterizations to delve into the underlying mechanisms of films with the integrated a-Si (i) layer, including surface microscopy, active dopants profile, crystallographic structure, elemental distribution, and electrical properties. Finally, we have fabricated the industrial-sized TOPCon solar cells with an average efficiency of 23.83 %, which is 0.25 % higher than that of Baseline counterparts (23.58 %) on the production line. The above results have demonstrated the introduction of a-Si (i) film can be a buffer layer, retarding the diffusion of phosphorus into the Si substrate and obtaining a better passivation effect, enabling us to further tailor the doping profile for high-efficiency solar cells. Our work highlights a promising strategy to improve the performance of TOPCon solar cells, showcasing the substantial potential for implementation in industrial manufacturing.

The effect of Al on microstructure and mechanical properties is investigated in novel Mg-6Y-3Zn (WZ63) alloys produced by high-pressure die-casting (HPDC). The morphology of (Al,Zn)2Y phase varies from lamellar to flower-like and then to block shape with 0.4-1.0 wt% Al. The HPDC alloys exhibit fine grain sizes ranging from 4 mu m to 7.4 mu m, and significant grain refinement is obtained with Al as low as 0.4 wt%, which is different from that in gravity casting. The (Al,Zn)2Y phase is the crack source, and the dimple depth and elongation (EL) reduce with increasing Al content. Still, all the studied HPDC WZ63-xAl alloys maintain excellent tensile properties, keeping 256-274 MPa for tensile strength (UTS) and 7.4-9.7 % EL at room temperature and 188-213 MPa UTS and 10-35 % EL at 250 degrees C. Optimal mechanical properties are obtained with Al content around 0.4-0.5 wt%.

Correction for ‘Local structure and lithium-ion diffusion pathway of cubic Li 7 La 3 Zr 2 O 12 studied by total scattering and the Reverse Monte Carlo method’ by Haolai Tian et al. , J. Mater. Chem. A , 2023, 11 , 25516–25533, https://doi.org/10.1039/D3TA04495E.

We found that the specific dispersion of metal-insulator-metal (MIM) waveguide allows the hybridization of surface plasmon polaritons (SPPs) and the waveguide, which is not possible with dielectric waveguides. The SPP-MIM hybridization structure forms such a meta-film that integrates the previously incompatible respective merits of SPR and LSPR, including flat interfaces, high sensitivities, short evanescent fields and easy coupling with confined light. On the other hand, to achieve stable and reproducible performance is one of the greatest unresolved challenges for the development of nanophotonic biosensors. We point out that the key is to obtain well-controlled biomolecular behaviors using simple physical interfaces, for which the SPP-MIM meta-film provides a capable solution. We embed the SPP-MIM meta-film with a plasmonic crystal cavity and integrate it on a single-mode fiber's end-facet to detect biomolecular interactions. This device demonstrates highly reproducible sensorgrams and convincing detection of biotinylated proteins at down to 30 fM, with the sensorgrams following the Langmuir model. By unprecedentedly having both high sensitivity and high reproducibility, our device proposal provides a comprehensive solution for optical fiber-tip plasmonic devices to turn into a useful industrial biosensing technology.

Conventional casting Mg alloys tend to lose strength quickly when exposed to elevated temperatures (200-300 degrees C). Here, we report a cast Mg alloy decorated by honeycomb LPSO structure via high pressure die casting, with an impressive strength of 191 MPa at 300 degrees C, exceeding all traditional cast Mg based alloys and common Al-Si alloys. Such remarkable strength ascribes to the strong geometric confinement of the LPSO cellular shell to grain boundaries and dislocations, coupled with extra strain hardening derived from dislocation interactions with stacking faults. In addition, non-basal and dislocations avoid macro-plastic instability at high strains.

The passivating contact concept stands out as one of the most promising and industrially viable photovoltaic (PV) technologies. Further improving the quality of physical contact has become a focus of ongoing research. The film blistering issue has been identified as one of the major bottlenecks for the polysilicon (poly-Si) films deposited by the PECVD approach. In this study, we investigated how the in-situ phosphorus (P) doping level within the poly-Si films contributes to the occurrence of blistering. Our investigations into the film blistering mechanisms reveal that a high in-situ P-doping suppresses hydrogen release levels and reduces the accumulation of residual stress during annealing, which leads to the blistering-free appearance, especially observed in heavily P-doped poly-Si films. However, as excessive P-doping could weaken the interfacial passivation quality, we propose a bi-layer structure of P-doped poly-Si films which allows the doping profile to be tailored and maintain good quality passivating contacts. Based on the bi-layer structure, we fabricated industrial-sized tunnel oxide passivated contact (TOPCon) solar cells, which attained an average efficiency of 23.84%. Our work not only presents a promising strategy for improving the performance of passivating contacts via the PECVD approach but also underscores the significant potential for its widespread implementation in industrial TOPCon solar cell manufacturing.

ABS T R A C T The temperature dependence of mechanical strength including yield strength (YS) and ultimate tensile strength (UTS) in HPDC WZA631 alloy is investigated in a wide temperature range from room temperature (RT) to 350 degrees C. It is found that at 25-300 degrees C, YS and UTS do not drop markedly, from 173 MPa and 274 MPa at RT to 113 MPa and 170 MPa at 300 degrees C, respectively. While above 300 degrees C the flow stress falls rather rapidly, to 74 MPa for YS and to 108 MPa UTS at 350 degrees C. The (Al,Zn)2Y phase exhibits similar behavior between 150 degrees C and 350 degrees C, breaking up under stress and becoming the relatively stable crack source without catastrophic cracking. The LPSO phase, keeping steady and excellent critical resolved shear stress (CRSS) below 250 degrees C, remains unchanged with complete network structure at 150 degrees C and 250 degrees C. Therefore, the LPSO phase reinforces the alloy with slow flow stress reduction at RT-300 degrees C for WZA631 alloy. The tensile property deteriorates above 300 degrees C due to the destruction of the network structure as well as the reduction of CRSS for the prismatic slip of LPSO under tensile loading. Thus, the LPSO phase determines the mechanical strength evolution of WZA631 alloy, which is similar to the behavior of gamma' phase in the Ni-based superalloys. Besides, the relationship between strength and temperature is described by the Arrhenius equation, which may be reduced to an exponential model in the form of sigma = a +bT for HPDC WZA631 alloy.

Li- and Mn-rich layered oxides (LMLOs) are promising cathode materials for Li-ion batteries (LIBs) owing to their high discharge capacity of above 250 mA h g-1. A high voltage plateau related to the oxidation of lattice oxygen appears upon the first charge, but it cannot be recovered during discharge, resulting in the so-called voltage decay. Disappearance of the honeycomb superstructure of the layered structure at a slow C-rate (e.g., 0.1 C) has been proposed to cause the first-cycle voltage decay. By comparing the structural evolution of Li[Li0.2Ni0.2Mn0.6]O2 (LLNMO) at various current densities, the operando synchrotron-based X-ray diffraction results show that the lattice strain in bulk LLNMO is continuously increased over cycling, resulting in the first-cycle voltage loss upon Li-ion insertion. Unlike the LLNMO, the accumulated average lattice strain of LiNi0.8Co0.1Mn0.1O2 (NCM811) and LiNi0.6Co0.2Mn0.2O2 (NCM622) from the open-circuit voltage to 4.8 V could be released on discharge. These findings help to gain a deep understanding of the voltage decay in LMLOs.

Tunnel oxide passivated contact (TOPCon) solar cells have gradually dominated the industrial silicon solar cells. In this paper, we have adopted the tube plasma-enhanced chemical vapor deposition (PECVD) technology integrating with nano SiOx(Tox) and in-situ phosphorus-doped polysilicon (n + poly-Si), in which Tox is pre-pared by plasma-assisted oxygen (O2) oxidation. Passivation and contact performance of TOPCon solar cells have been investigated under different thicknesses of Tox, and the following simulation has confirmed the optimal electrical properties, i.e., the implied open-circuit voltage (iVOC) of the hydrogenated lifetime sample is promoted to more than 736.1 mV on the textured wafer, corresponding to a lowest single-sided saturation current density (J0) of 4.6 fA/cm2, and the contact resistivity of 1.55 m omega cm2 extracted from the transmission line method. Characterizations are carried out to conform the rear stack passivation layers satisfy the requirement of the high -efficiency TOPCon solar cells. Finally, we have fabricated the large-sized TOPCon solar cells with an average efficiency of 24.5% and a maximum efficiency of 24.7%, respectively. The above work has demonstrated the tube PECVD technology integrating with plasma-assisted O2 oxidation and in-situ doped poly-Si has the potential for the mass-production TOPCon in industry.

All-inorganic perovskite halide semiconductors have been noticed for applications in photovoltaics, light-emitting diodes, lasers, and photodetectors, thanks to their exceptional optoelectronic characteristics. As a typical example, CsGeI3 was previously investigated in the forms of quantum dots and thin films. Here, we developed a technique based on aqueous solution to synthesize millimeter-level-sized CsGeI3 single crystals. The ferroelectric and photoelectric functionalities of the as-grown crystals were examined and compared with the prediction from density functional theory calculation. These findings not only provide a new route to make germanium-based perovskite single crystals but also introduce possible prospects for ferroelectric photovoltaics.

Passivating contact solar cells have gradually become the mainstream cell technology due to their excellent performance, and further improving the conversion efficiency has become a focus of subsequent research. Typically, achieving excellent field-effect passivation and low contact resistivity in doped polycrystalline silicon (poly-Si) solar cells requires heavy phosphorus doping. However, this approach can lead to a predicament where excessive phosphorus diffuses into the Si substrate during annealing, causing recombination losses. To address this challenge, a tandem passivation contact structure incorporating an intrinsic amorphous silicon (a-Si ( i )) film within the passivation layers is introduced to retard the diffusion of phosphorus into the Si substrate. Comprehensive characterizations of the tandem structure were carried out to delve into the underlying mechanisms of films with the integrated a-Si ( i ) layer, including simulations, surface microscopy, active dopants profiling, crystallographic structure, chemical bonding, elemental distribution, and electrical properties. Simulations revealed that the inserted intrinsic layer effectively counteracts the clustering of phosphorus atoms, leading to a more even distribution during crystal growth. Furthermore, active dopant profiles indicate the potential of the introduced a-Si ( i ) layer to tailor the in-diffused dopant profile. Microscopy investigations revealed the occurrence of blistering when the a-Si ( i ) thickness exceeds 30 nm. Passivation and contact performances of TOPCon solar cells were assessed as the a-Si ( i ) thickness was varied. Notably, optimal electrical properties were achieved with 20 nm a-Si ( i ) thickness. At this thickness, the implied open-circuit voltage ( iV ) of the hydrogenated lifetime sample was promoted to more than 736.6 mV on the polished wafer, corresponding to the lowest single-side saturation current density ( J ) of 4.3 fA/cm . In addition, a low contact resistivity of 1.4 mΩ·cm was achieved. Based on this tandem passivation contact structure, industrial-sized TOPCon solar cells were fabricated, giving an average efficiency of 23.83%, 0.25% higher than that of the baseline counterparts on the production line. The above results demonstrate the role of the a-Si ( i ) film as a buffer layer, retarding the diffusion of phosphorus into the Si substrate and obtaining a better passivation effect. This enables us to further tailor the doping profile for high-efficiency solar cells. Our work thus highlights a promising strategy to improve the performance of TOPCon solar cells and showcases its potential for implementation in industrial manufacturing.

The cubic phase of Li 7 La 3 Zr 2 O 12 shows fast diffusion of the lithium ions. Combining total scattering measurements analysed by the RMC method with molecular dynamics simulations gives a detailed picture of the distribution of the Li + ions.

The anomalous photocurrent in perovskite CsGeX3 (X = Cl, Br, I), which is enhanced by spontaneous polarization, has recently attracted the attention of both theoretical and experimental researchers. However, the underlying mechanism of ferroelectric-optical coupling remains an open question that requires further investigation. The polarization displacements in our grown single-crystal perovskite structure in CsGeX3 (X = Cl, Br, I) are from the Ge2+ ion distortion based on the calculation of the synchrotron radiation X-ray pair distribution function. Furthermore, we carry out the simulations of the photocurrent in CsGeX3 halides by means of nonequilibrium Green's function (NEGF) method. To examine the effect of polarized light irradiation on the CsGeX3 structures, we calculated the induced photocurrents with different transport directions. The theoretical results indicated that the photocurrents were influenced by diverse halogens at the X site in perovskite CsGeX3.

In this work, the thermophysical properties of a novel high pressure die casting (HPDC) Mg–RE (Mg–6Y–3Zn–1Al, WZA631 in wt pct) alloy are well investigated at the range of 298–673 K, compared with common HPDC AE44 alloy. Results show that the thermal expansion coefficients and thermal conductivity of AE44 and WZA631 alloys have similar temperature dependence, i.e., their values increase with temperature. At the same condition, the AE44 alloy exhibits higher thermal conductivity, while the WZA631 alloy has a lower expansion coefficient (better thermal stability). The lower thermal expansion coefficient of the WZA631 alloy is associated with the improved matrix deformability due to Y atoms and the strong barrier effect provided by the uniformly distributed long period stacking ordered (LPSO) phase. For the higher thermal conductivity of the AE44 alloy, trace cell boundary defects and solute-induced weak lattice distortions are major contributors. The numerical thermal conductivity models for both alloys are established based on Matthiessen’s rule, which presents reasonable consistency with experimental data, having correlation factors of R 2 = 0.99. Also, with respect to some available gravity casting/die casting Mg alloys, the developed die casting WZA631 alloy demonstrates great merits from aspects of thermophysical properties, strength, and plasticity.