Lifetime Evolution Research Articles

How Lifetime Evolution of Parkinson's Disease Could Shape Clinical Trial Design: A Shared Patient-Clinician Viewpoint.

Parkinson's disease (PD) has a long, heterogeneous, pre-diagnostic phase, during which pathology insidiously accumulates. Increasing evidence suggests that environmental and lifestyle factors in early life contribute to disease risk and progression. Thanks to the extensive study of this pre-diagnostic phase, the first prevention trials of PD are being designed. However, the highly heterogenous evolution of the disease across the life course is not yet sufficiently taken into account. This could hamper clinical trial success in the advent of biological disease definitions. In an interdisciplinary patient-clinician study group, we discussed how an approach that incorporates the lifetime evolution of PD may benefit the design of disease-modifying trials by impacting population, target and outcome selection. We argue that the timepoint of exposure to risk and protective factors plays a critical role in PD subtypes, influencing population selection. In addition, recent developments in differential disease mechanisms, aided by biological disease definitions, could impact optimal treatment targets. Finally, multimodal biomarker panels using this lifetime approach will likely be most sensitive as progression markers for more personalized trials. We believe that the lifetime evolution of PD should be considered in the design of clinical trials, and that such initiatives could benefit from more patient-clinician partnerships.

Photooxidation triggered ultralong afterglow in carbon nanodots

It remains a challenge to obtain biocompatible afterglow materials with long emission wavelengths, durable lifetimes, and good water solubility. Herein we develop a photooxidation strategy to construct near-infrared afterglow carbon nanodots with an extra-long lifetime of up to 5.9 h, comparable to that of the well-known rare-earth or organic long-persistent luminescent materials. Intriguingly, size-dependent afterglow lifetime evolution from 3.4 to 5.9 h has been observed from the carbon nanodots systems in aqueous solution. With structural/ultrafast dynamics analysis and density functional theory simulations, we reveal that the persistent luminescence in carbon nanodots is activated by a photooxidation-induced dioxetane intermediate, which can slowly release and convert energy into luminous emission via the steric hindrance effect of nanoparticles. With the persistent near-infrared luminescence, tissue penetration depth of 20 mm can be achieved. Thanks to the high signal-to-background ratio, biological safety and cancer-specific targeting ability of carbon nanodots, ultralong-afterglow guided surgery has been successfully performed on mice model to remove tumor tissues accurately, demonstrating potential clinical applications. These results may facilitate the development of long-lasting luminescent materials for precision tumor resection.

Synthesis-Kinetics of Violet- and Blue-Emitting Perovskite Nanocrystals with High Brightness and Superior Stability toward Flexible Conversion Layer.

The low photoluminescence (PL) efficiency and unstable features of small blue-emitting CsPbX3 nanocrystals (NCs) greatly limit their applications in optoelectronics field. Herein, the synergistic and post-treatment kinetics are studied to create highly bright and anomalous stable violet (peak position of ≈408nm) and blue (peak position of ∼ 466nm) emitting perovskite NCs. Ligand and ion exchange mechanism are systematic studied by the evolution of absorption, PL, and fluorescence lifetime to evaluate ligand bonding, defect engineering, and non-radiative recombination. Didodecyl dimethyl mmonium chloride (DDAC) and CuX2 post-synergistictreatment created DDAC-CsPbCl3-CuCl2 and DDAC-CsPbCl3-CuBr2 NCs that remained the phase composition, morphology, and size of CsPbCl3 NCs. The PL efficiencies are drastically increased to 42 and 85% for violet- and blue-emitting NCs, respectively. The stability test indicated that the NCs enable against various harsh conditions (e.g., ultraviolet light irradiation and heat-treatment). The NCs retained their initial PL efficiency after 2 months under ambient conditions and UV light irradiation. These NCs also exhibited high stability after heat-treatment at 120°C. The emitting NCs embedded in flexible films still revealed bright PL and high stability, suggesting current results provide a new avenue for the application in the field of optoelectronics.

A Closer Look at the Evolution of Supercooled Cloud Droplet Temperature and Lifetime in Different Environmental Conditions with Implications for Ice Nucleation in the Evaporating Regions of Clouds

Abstract This study investigates the evolution of temperature and lifetime of evaporating, supercooled cloud droplets considering initial droplet radius (r0) and temperature (), and environmental relative humidity (RH), temperature (T∞), and pressure (P). The time (tss) required by droplets to reach a lower steady-state temperature (Tss) after sudden introduction into a new subsaturated environment, the magnitude of ΔT = T∞ − Tss, and droplet survival time (tst) at Tss are calculated. The temperature difference (ΔT) is found to increase with T∞, and decrease with RH and P. ΔT was typically 1–5 K lower than T∞, with highest values (∼10.3 K) for very low RH, low P, and T∞ closer to 0°C. Results show that tss is <0.5 s over the range of initial droplet and environmental conditions considered. Larger droplets (r0 = 30–50 μm) can survive at Tss for about 5 s to over 10 min, depending on the subsaturation of the environment. For higher RH and larger droplets, droplet lifetimes can increase by more than 100 s compared to those with droplet cooling ignored. Tss of the evaporating droplets can be approximated by the environmental thermodynamic wet-bulb temperature. Radiation was found to play a minor role in influencing droplet temperatures, except for larger droplets in environments close to saturation. The implications for ice nucleation in cloud-top generating cells and near cloud edges are discussed. Using Tss instead of T∞ in widely used parameterization schemes could lead to enhanced number concentrations of activated ice-nucleating particles (INPs), by a typical factor of 2–30, with the greatest increases (≥100) coincident with low RH, low P, and T∞ closer to 0°C. Significance Statement Cloud droplet temperature plays an important role in fundamental cloud processes like droplet growth and decay, activation of ice-nucleating particles, and determination of radiative parameters like refractive indices of water droplets. Near cloud boundaries such as cloud tops, dry air mixes with cloudy air exposing droplets to environments with low relative humidities. This study examines how the temperature of a cloud droplet that is supercooled (i.e., has an initial temperature < 0°C) evolves in these subsaturated environments. Results show that when supercooled cloud droplets evaporate near cloud boundaries, their temperatures can be several degrees Celsius lower than the surrounding drier environment. The implications of this additional cooling of droplets near cloud edges on ice particle formation are discussed.

Differential sputtering yield measurement of ion grid materials by novel arch array system

In this experimental study the differential sputtering yield and total sputtering yield of ion thruster grid materials (Mo and C/C composite) under low-energy ion bombardment has been investigated. A novel combinable aluminum arch array is developed to determine the spatial distributions of sputtered atoms in different azimuthal angles. The quartz crystal microbalance (QCM) method is used to validate the typical distribution profile of sputtered atoms at the 180° azimuthal angle. The distribution characteristics of sputtered atoms as well as the specific regions of maximum differential sputtering yield under different incident energies, incident angles and ion species (Xe, Kr, Ar) have been discussed. The sputtering resistance performance of C/C composite materials have been compared with Mo metal by measuring the total sputtering yield. The spatial distributions of C/C differential sputtering yield are found highly anisotropic even under normal incidence, a multi-region discontinuous distribution characteristic of maximum differential sputtering yield have been observed in C/C composite material. The experimental results about the spatial distribution of sputtered atoms are of great importance for establishing the sputter-redeposition models of grid apertures to accurately predict the evolution of grid morphology and lifetime of ion thruster.

Do Optically Denser Trade‐Wind Cumuli Live Longer?

AbstractThis study investigates the lifetime and temporal evolution of physical properties of trade‐wind cumuli based on tracking individual clouds in observations with the Advanced Baseline Imager aboard the geostationary GOES‐16 satellite during the “ElUcidating the RolE of Cloud–Circulation Coupling in ClimAte” (EUREC4A) campaign east of Barbados in winter 2020. A first application of our upgraded cloud‐tracking toolbox to measurements with high spatio‐temporal resolution (2 × 2 km2 and 1 min) provides probability density functions of lifetime and area of clouds that develop as a consequence of meso‐to‐synoptic scale motions. By separately considering clouds that exist during daytime and live in distinct lifetime intervals, we find that shallow marine cumuli live longer when they cover a larger surface area and show higher cloud optical thickness (COT). Besides the effect of COT, the scale of the atmospheric motions with which the clouds interact is also critical to their lifetime.

Thickness-dependent Auger scattering in a single WS2 microcrystal probed with time-resolved terahertz near-field microscopy.

Time-resolved terahertz (THz) spectroscopy has been shown as a powerful technique to non-invasively determine the charge carrier properties in photoexcited semiconductors. However, the long wavelengths of terahertz radiation reduce the applicability of this technique to large samples. Using THz near-field microscopy, we show THz measurements of the lifetime of 2D single exfoliated microcrystals of transition metal dichalcogenides (WS2). The increased spatial resolution of THz near-field microscopy allows spatial mapping of the evolution of the carrier lifetime, revealing Auger assisted surface defect recombination as the dominant recombination channel. THz near-field microscopy allows for the non-invasive and high-resolution investigation of material properties of 2D semiconductors relevant for nanoelectronic and optoelectronic applications.

Influence of Increasing Mean Stress on Fatigue Properties of Shale during Pulsating Hydraulic Fracturing

During pulsating hydraulic fracturing (PHF), reservoir rock can be subjected to constant amplitude, constant mean stress (CACMS) cyclic loading or constant amplitude, increasing mean stress (CAIMS) cyclic loading. The influence of increasing mean stress on rock fatigue strength, fatigue lifetime, fatigue damage, and energy evolution of shale is rarely investigated, and which type of cyclic loading is more efficient for PHF has not been determined and demonstrated. In this Article, a series of uniaxial compression tests under these two types of cyclic loading are first conducted. A fatigue lifetime model for CAIMS is established. The shale strength and fatigue lifetime for CACMS and CAIMS are then compared. Their differences are explained by their dissipated energy density evolution and damage evolution. Finally, a nonlinear damage accumulation model to predict damage evolution for CAIMS cyclic loading is proposed. It is suggested that CAIMS is a better cyclic loading type when its amplitude is higher than 30% UCS (uniaxial compressive strength) of rock. This provides a meaningful amplitude threshold for CAIMS parameter optimization in the PHF construction. In this case, compared with CACMS cyclic loading, CAIMS cyclic loading significantly decreases the shale strength by up to 20% UCS and the fatigue lifetime from over 500 to 9. Different from an inverted-S-shaped damage evolution for CACMS cyclic loading, damage evolution for CAIMS cyclic loading exhibits a monotonic increasing trend. The damage variable growth rates of CACMS and CAIMS both show a three-stage trend: (1) their growth rates both decrease; (2) the growth rate for CACMS remains stable, while for CAIMS its growth rate slowly increases; and (3) their growth rates both increase sharply. Correspondingly, the dissipated energy density evolutions for CACMS and CAIMS show a similar three-stage trend. It can be concluded that during the second stage, for CAIMS microfractures and plastic deformation inside specimens are developed and accumulated more and faster than those for CACMS cyclic loading. This explains the phenomenon that the fatigue lifetime and strength of CAIMS cyclic loading are less than those of CACMS. The nonlinear damage accumulation model proposed in this Article can well fit experimental results. This model can be used for accurately describing reservoir rock mechanical property degradation during hydraulic fracture simulation induced by PHF.

Solar ring mission: Building a panorama of the Sun and inner-heliosphere

Solar Ring (SOR) is a proposed space science mission to monitor and study the Sun and inner heliosphere from a full 360° perspective in the ecliptic plane. It will deploy-three 120°-separated spacecraft on the 1-AU orbit. The first spacecraft, S1, locates 30° upstream of the Earth, the second, S2, 90° downstream, and the third, S3, completes the configuration. This design with necessary science instruments, e.g., the Doppler-velocity and vector magnetic field imager, wide-angle coronagraph, and in-situ instruments, will allow us to establish many unprecedented capabilities: (1) provide simultaneous Doppler-velocity observations of the whole solar surface to understand the deep interior, (2) provide vector magnetograms of the whole photosphere — the inner boundary of the solar atmosphere and heliosphere, (3) provide the information of the whole lifetime evolution of solar featured structures, and (4) provide the whole view of solar transients and space weather in the inner heliosphere. With these capabilities, Solar Ring mission aims to address outstanding questions about the origin of solar cycle, the origin of solar eruptions and the origin of extreme space weather events. The successful accomplishment of the mission will construct a panorama of the Sun and inner-heliosphere, and therefore advance our understanding of the star and the space environment that holds our life.

Topological Feature Tracking for Submesoscale Eddies

AbstractCurrent state‐of‐the art procedures for studying modeled submesoscale oceanographic features have made a strong assumption of independence between features identified at different times. Therefore, all submesoscale eddies identified in a time series were studied in aggregate. Statistics from these methods are illuminating but oversample identified features and cannot determine the lifetime evolution of the transient submesoscale processes. To this end, the authors apply the Topological Feature Tracking (TFT) algorithm to the problem of identifying and tracking submesoscale eddies over time. TFT identifies critical points on a set of time‐ordered scalar fields and associates those points between consecutive timesteps. The procedure yields tracklets which represent spatio‐temporal displacement of eddies. In this way we study the time‐dependent behavior of submesoscale eddies, which are generated by a 1‐km resolution submesoscale‐permitting model. We summarize the submesoscale eddy data set produced by TFT, which yields unique, time‐varying statistics.

Tailoring linear and nonlinear surface plasmon responses in borophene nanostructures

The newly reported 2D material ‘borophene’ provides a novel building block for nanoscale materials and devices. In this work, the linear and nonlinear plasmonic response of the electric dipole (ED) moment in metallic borophene is theoretically investigated. In our proposed model, a borophene nanostructure is deposited on the top of a dielectric layer sandwich with a silver layer acting as a mirror. It was found that the scattering at the scattering peak originates mainly from the exciting total ED. Our calculations demonstrate that scattering in the proposed model can be tuned well with carrier relaxation time, effective electron mass and free carrier density. The strongly localized fundamental field induces the desired increase in the second harmonic wave, which is discussed in detail by introducing the second-order nonlinear source. In addition, the evolution of the lifetime of linear and nonlinear plasmonic modes is also investigated, which helps us to study the underlying mechanism of microprocessing in the borophene plasmonic–photonic interaction. The manipulation of plasmonic behaviour and lifetime evolution makes borophene an excellent platform for tunable plasmonic–photonic devices.

Surface coatings of two-dimensional metal-organic framework nanosheets enable stable zinc anodes

Aqueous zinc-ion batteries (ZIBs) have been considered as safe and scalable energy storage solutions, but the dendrite and corrosion issues of Zn anodes have hindered their further application. Herein, we demonstrate that two-dimensional metal-organic framework (MOF) nanosheets can act as protective coatings to prevent dendrite formation and hydrogen evolution of Zn anodes. The morphology of MOFs was tuned from octahedral nanoparticles (UiO-67-3D) to nanosheets (UiO-67-2D), leading to significantly enhanced protective performance. UiO-67-2D nanosheets-coated Zn anodes displayed smaller polarization, longer cycling lifetime and lower H2 evolution than those of UiO-67-3D nanoparticles in symmetrical cells, which has been attributed to the higher concentration of surface Zr−OH/H2O to induce uniform Zn deposition and one-dimensional (1D) channels perpendicular to the Zn surface to regulate Zn2+ diffusion. The assembled UiO-67-2D@Zn∥Mn2O3/C full cell shows a high capacity of 240 mAh g−1 at 1 A g−1 and excellent cycling stability.

Unveiling the phonon effect on the narrow-band deep-red emission from solution-combustion synthesized Mn4+ doped CaYAlO4 microcrystals

In this study, we report a unique solution-combustion synthesis of Mn4+ doped CaYAlO4 microcrystals and demonstrate a narrow-band deep-red emission. Through the simulation of low-temperature photoluminescence (PL) spectroscopy and theoretical fitting on temperature-dependent PL intensity at T < 400 K, we obtained a dominant phonon mode with energy of 40 meV during the vibronic coupling process, with a small Huang-Rhys factor of S= 0.68. From the analysis of the measured PL lifetime evolution of Mn4 + doped CaYAlO4, it is found that luminescence thermal quenching effect was mainly attributed to four-dominant phonon interaction with Mn4+ electronic states. More interestingly, the deviation of luminescence decay curve from the single-exponential mode at T > 400 K suggests that the occurrence of two radiative transitions is a consequence of ionically thermal excitation to the second excited state of 4T2. These findings provide not only a general approach to identify the predominant phonon vibration, but also deep insights into the effect of weak electron-phonon coupling on PL properties of solid-state luminescent.

Directed Evolution of a Bright Variant of mCherry: Suppression of Nonradiative Decay by Fluorescence Lifetime Selections.

The approximately linear scaling of fluorescence quantum yield (ϕ) with fluorescence lifetime (τ) in fluorescent proteins (FPs) has inspired engineering of brighter fluorophores based on screening for increased lifetimes. Several recently developed FPs such as mTurquoise2, mScarlet, and FusionRed-MQV which have become useful for live cell imaging are products of lifetime selection strategies. However, the underlying photophysical basis of the improved brightness has not been scrutinized. In this study, we focused on understanding the outcome of lifetime-based directed evolution of mCherry, which is a popular red-FP (RFP). We identified four positions (W143, I161, Q163, and I197) near the FP chromophore that can be mutated to create mCherry-XL (eXtended Lifetime: ϕ = 0.70; τ = 3.9 ns). The 3-fold higher quantum yield of mCherry-XL is on par with that of the brightest RFP to date, mScarlet. We examined selected variants within the evolution trajectory and found a near-linear scaling of lifetime with quantum yield and consistent blue-shifts of the absorption and emission spectra. We find that the improvement in brightness is primarily due to a decrease in the nonradiative decay of the excited state. In addition, our analysis revealed the decrease in nonradiative rate is not limited to the blue-shift of the energy gap and changes in the excited state reorganization energy. Our findings suggest that nonradiative mechanisms beyond the scope of energy-gap models such the Englman-Jortner model are suppressed in this lifetime evolution trajectory.

Simulation of the evaporation/boiling transition for the vaporization of a bi-component droplet under wide-temperature environments

A boiling model was proposed and coupled with a quasi-dimensional evaporation model to simulate the vaporization of a bi-component droplet under wide-temperature environments. Different from previous droplet evaporation models, the transition between droplet evaporation and boiling was especially focused on in this study. In the boiling model, the bubble point temperature of the bi-component mixture was employed to determine the critical condition for the occurrence of the boiling phenomenon. The mass rate of the boiling vaporization of the droplet was calculated by combining the heterogeneous nucleation model, bubble growth model, and bubble fragmentation model. Based on the measurements of the vaporization of an n-heptane/n-hexadecane droplet, the results indicate that the present vaporization model can satisfactorily reproduce the droplet lifetime and diameter evolution under wide ambient temperatures. The simulation results of the vaporization process are greatly affected by the boiling mass rate as the droplet enters the boiling stage. The heterogeneous nucleation rate is the main factor affecting the boiling mass rate, and the decrease of effective thermal conductivity slows down the overall droplet vaporization rate.

Rolling Bearing Fault Diagnosis Based on Deep Learning and Autoencoder Information Fusion

The multisource information fusion technique is currently one of the common methods for rolling bearing fault diagnosis. However, the current research rarely fuses information from the data of different sensors. At the same time, the dispersion itself in the VAE method has asymmetric characteristics, which can enhance the robustness of the system. Therefore, in this paper, the information fusion method of the variational autoencoder (VAE) and random forest (RF) methods are targeted for subsequent lifetime evolution analysis. This fusion method achieves, for the first time, the simultaneous monitoring of acceleration signals, weak magnetic signals and temperature signals of rolling bearings, thus improving the fault diagnosis capability and laying the foundation for subsequent life evolution analysis and the study of the fault–slip correlation. Drawing on the experimental procedure of the CWRU’s rolling bearing dataset, the proposed VAERF technique was evaluated by conducting inner ring fault diagnosis experiments on the experimental platform of the self-research project. The proposed method exhibits the best performance compared to other point-to-point algorithms, achieving a classification rate of 98.19%. The comparison results further demonstrate that the deep learning fusion of weak magnetic and vibration signals can improve the fault diagnosis of rolling bearings.

Nanostructure, Optical and Optoelectronic Properties of Silver Nanoparticle- based Chemical Etching on Monocrystalline Silicon for Solar Cell Applications

Introduction: Silver nanoparticle (AgNP)-based chemical etching is applied to produce silicon nanowires (SiNWs) on monocrystalline silicon. Methods: The effect of etching time on the production of silicon nanowires and on optical and optoelectronic properties was studied. Results: Using this approach, surface recombination velocity (Seff) and the effective lifetime (τeff) evolution of SiNWs after passivation were improved, and SiNWs obtained in the optimal time of 20 min, exhibited shallow reflection of 1% in the wavelength range of 300–1100 nm. Conclusion: Thus, passivated solar cell-based SiNWs in an HF/HNO3/H2O solution were essential for increasing the efficiency of solar cell-based SiNWs from 9% to nearly 15%.

Fluorescence lifetime evolution of crude oils during thermal cracking: Implications from pyrolysis experiments in a closed system

In this study, pyrolysis experiments were performed on two crude oils with different origins in a closed system, and the pyrolyzed oils were then analyzed for spectral parameters, including fluorescence lifetime, fluorescence spectra and infrared spectra, as well as for gross chemical compositions. The results show that the evolution of the fluorescence lifetime of crude oil (τoil) can be divided approximately into two stages during oil cracking. With the increasing extent of oil cracking (PC), the τoil first increases at the early cracking stage of PC < 40%, and then it decreases at the late cracking stage of PC > 40%. The type and concentration of aromatics in crude oils, which can be respectively characterized by the fluorescence lifetime of aromatics (τaro) and the saturates/aromatics ratio (Rsat/aro) of the oils, largely control the fluorescence quantum yield and fluorescence quenching degree of the oils, respectively, and thus the changes in the two factors during oil cracking determine the fluorescence lifetime evolution of crude oils. The differences in fluorescence lifetime of the crude oils that are sourced from diverse types of organic matter cannot be masked by the oil cracking process when the PC is smaller than 80%. Combined with fluorescence or infrared spectral data, the fluorescence lifetime potentially can be applied to discriminate oils of various origins in petroleum reservoirs, especially in deep, light oil/condensate reservoirs where biomarker concentration is extremely low.

Kinetics of light and elevated temperature-induced degradation in cast mono p-type silicon

Cast mono Silicon (Si) technology has the advantages of low cost, i.e., multicrystalline silicon (mc-Si), and high efficiency, i.e., Czoch-ralski-grown silicon (Cz-Si). Cast mono Si has a similar performance to current Cz-Si counterparts with a solar cell structure, i.e., a passivated emitter and rear cell (PERC). However, the severity of light and elevated temperature-induced degradation (LeTID) on cast mono Si solar cells may be similar to mc-Si, not Cz-Si. To clarify the LeTID kinetics in the p-type cast mono silicon, we observed the effect that LeTID had on the carrier lifetime. First, a series of carrier lifetime measurements were performed to investigate LeTID kinetics in the accelerated regeneration process via high intensity illumination at elevated temperatures and modulating kinetics via dark annealing before illumination. Next, we documented the evolution of a carrier lifetime to investigate the stability of regenerated state at 75 °C and light intensity of ~ 1 kW/m2. The results show that the effect of dark annealing on LeTID kinetic modulation could be explained by the B-H defect precursor concentration and defect reservoir theory, which originate from the results for mc-Si. An accelerated regeneration method that combines dark annealing and illumination, with high intensity at an elevated temperature, can yield a higher value and improved LeTID stability in terms of the lifetime, as compared with illumination without pre-annealing. This implies that this mixed process may be a potential method to provide both improved performance and high anti-LeTID properties in Si PERC solar cells.

Role of the Polar Electric Field in Bismuth Oxyhalides for Photocatalytic Water Splitting.

The built-in electric field generated by polar materials is one of the most effective strategies to promote the separation of photogenerated electron-hole pairs in the field of photocatalysis. However, because of the complexity and diversity of the built-in electric field in polar materials, it is not clear how to enhance the photocatalytic performance and how to control the polar electric field effectively. To this end, four-layered bismuth oxyhalides, BiOX, and BiOXO3 (X = Br, I) were synthesized by a simple hydrothermal method. X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analysis confirmed that they all have the structure characteristics of a sillenite phase. Scanning electron microscopy images show that they all have the morphology of nanosheets. Among them, BiOBrO3 was successfully synthesized and characterized for the first time in the present work. The order of photocatalytic performance (including carrier's lifetime, photocurrent density, and H2 evolution rate) of the four compounds is listed as follows: BiOBrO3 > BiOI > BiOIO3 > BiOBr. In the bulk of the BiOXO3 photocatalyst, the spontaneous polar built-in electric field along the [001] direction is the crucial factor to inhibit the recombination of photogenerated electron-hole pairs, while the surface polar electric field in BiOI can outstandingly inhibit the recombination of photogenerated electron-hole pairs due to the breaking of the mirror symmetry. Therefore, regulating the microstructure and composition of the structure unit, which generates the built-in electric field, can indeed control the magnitude, direction, and effects of built-in electric fields. In practice, we should carefully adjust the strategy according to the actual situation so as to reasonably design and use the polar electric field, giving full play to its role and enhancing the photocatalytic performance.