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In recent years, halide perovskite solar cells (HPSCs) have attracted a great attention due to their superior photoelectric performance and the low‐cost of processing their quality films. In order to commercialize HPSCs, the researchers are focusing on developing high‐performance HPSCs. Many strategies have been reported to increase the power conversion efficiency and the long‐term stability of HPSCs over the past decade. Herein, we review the latest efforts and the chemical‐physical principles for preparing high‐efficiency and long‐term stability HPSCs in particular, concentrating on the perovskite materials, technologies for perovskite films, charge transport materials and ferroelectric effect to reduce the carrier loss, and photon management via plasmonic and upconversion effects. Finally, the key issues for future researches of HPSCs are also discussed with regard to the requirements in practical application. This review mainly reported the recent efforts to develop the high‐performance halide perovskites solar cells with high‐efficiency and long‐term stability by perovskite engineering (including crystal structure, dimension, and components of halide perovskites), film engineering (including preparation technology and defect passivation), carrier engineering (including charge transport materials and ferroelectric effect), and photon engineering (including plasmonic and upconversion).

Recent years have witnessed the accelerated development of optoelectronic devices based on lead halide perovskites‐based nanocrystal (NC) films. Yet, to date we have limited knowledge on how the NC's surface affects the long‐range charge‐carrier dynamics in these films. In this work, we exchange the native ligands on the surface of CsPbI3 NCs with three different thiopheneammonium‐based ligands. Among them, the custom‐synthesized 2‐thiophenepropenammonium iodide (TPAI) is found to significantly affect the collective phonon states in the NC films, and specifically decrease the strength of the carrier‐lattice interactions (by ∼half when compared to the other thiopheneammonium‐based ligands). This in turns promoted the formation of large polarons, which are beneficial for charge‐carrier dynamics. By employing the TPAI‐optimized CsPbI3 NC films to fabricate solar cells, a champion efficiency of 16.67% is achieved. Additionally, TPAI fostered excellent device stability in ambient air (91.8 ± 0.4% of the initial efficiency after 1100 h) and under light soaking conditions (84.6% after 1000 h). This work provides a rationale connecting the type of surface ligand molecules with the strength of carrier‐lattice interactions, thus proving additional insights into mechanisms governing charge‐carrier dynamics in NC film‐based devices. We developed a custom‐synthesized ligand, 2‐thiophenepropenammonium iodide, to exchange the native ligands capped on inorganic perovskite nanocrystals (NCs), and identified that the significantly decreased strength of electron‐phonon interaction benefited the charge‐carrier dynamics in their assembled films. This approach enabled a champion efficiency of 16.67% (near to field record) and excellent stability for NC‐based solar cell devices.

HighlightsThe g-C3N4 isotype heterojunction was synthesized for photocatalytic CO2 reduction, which exhibits an impressive activity and outstanding stability.The isotype heterojunction presents more favorable charge separation and transfer performance than the single components.The enhanced photogenerated charge dynamics in isotype heterojunction facilitates the production of key intermediates and thus the whole reaction kinetics.Photocatalytic conversion of CO2 to high-value products plays a crucial role in the global pursuit of carbon–neutral economy. Junction photocatalysts, such as the isotype heterojunctions, offer an ideal paradigm to navigate the photocatalytic CO2 reduction reaction (CRR). Herein, we elucidate the behaviors of isotype heterojunctions toward photocatalytic CRR over a representative photocatalyst, g-C3N4. Impressively, the isotype heterojunctions possess a significantly higher efficiency for the spatial separation and transfer of photogenerated carriers than the single components. Along with the intrinsically outstanding stability, the isotype heterojunctions exhibit an exceptional and stable activity toward the CO2 photoreduction to CO. More importantly, by combining quantitative in situ technique with the first-principles modeling, we elucidate that the enhanced photoinduced charge dynamics promotes the production of key intermediates and thus the whole reaction kinetics.

Estimating the state-of-charge (SOC) of lithium-ion batteries faces three main challenges at present: ensuring accuracy, achieving smooth output, and maintaining low computational complexity. To tackle these issues, this study introduces a hybrid algorithm observer. This approach combines the proportional-integral (PI) principle with the Kalman filter, utilizing a state-of-charge dynamics model and a current dynamics model. The SOC dynamics model, described by a differential equation, is developed to improve estimation accuracy. Meanwhile, the current dynamics model supports the design of a PI observer, which offers a low-complexity solution for SOC estimation. To address the issue of white noise in measurement signals, a one-dimensional Kalman filter is applied. This filter smooths the output signal and enhances accuracy by addressing the limitations of the PI observer. In addition, the system incorporates parameter observation to estimate key battery parameters. The hybrid observer was tested in a real vehicle to validate its effectiveness. Experimental results and statistical analysis demonstrate that this algorithm is a strong candidate for accurately estimating SOC in lithium-ion batteries.

Photocatalytic solar‐to‐fuel conversion over metal halide perovskites (MHPs) has recently attracted much attention, while the roles of defects in MHPs are still under debate. Specifically, the mainstream viewpoint is that the defects are detrimental to photocatalytic performance, while some recent studies show that certain types of defects contribute to photoactivity enhancement. However, a systematic summary of why it is contradictory and how the defects in MHPs affect photocatalytic performance is still lacking. In this review, the innovative roles of defects in MHP photocatalysts are highlighted. First, the origins of defects in MHPs are elaborated, followed by clarifying certain benefits of defects in photocatalysts including optical absorption, charge dynamics, and surface reaction. Afterward, the recent progress on defect‐related MHP photocatalysis, i.e., CO2 reduction, H2 generation, pollutant degradation, and organic synthesis is systematically discussed and critically appraised, putting emphasis on their beneficial effects. With defects offering peculiar sets of merits and demerits, the personal opinion on the ongoing challenges is concluded and outlining potentially promising opportunities for engineering defects on MHP photocatalysts. This critical review is anticipated to offer a better understanding of the MHP defects and spur some inspiration for designing efficient MHP photocatalysts. The recent progress on defect engineering of metal halide perovskites (MHPs) for photocatalysis is summarized and reexamined, focusing on discussing and critically appraising the benefits of defects, together with outlining potentially promising opportunities and directions for moving MHP‐based photocatalysis research forward.

Ensembles of negatively charged nitrogen-vacancy centers (NV−) in diamond have been proposed for sensing of magnetic fields and paramagnetic agents, and as a source of spin-order for the hyperpolarization of nuclei in magnetic resonance applications. To this end, strongly fluorescent nanodiamonds (NDs) represent promising materials, with large surface areas and dense ensembles of NV−. However, surface effects tend to favor the less useful neutral form, the NV0 centers, and strategies to increase the density of shallow NV− centers have been proposed, including irradiation with strong laser power (Gorrini in ACS Appl Mater Interfaces. 13:43221–43232, 2021). Here, we study the fluorescence properties and optically detected magnetic resonance (ODMR) of NV− centers as a function of laser power in strongly fluorescent bulk diamond and in nanodiamonds obtained by nanomilling of the native material. In bulk diamond, we find that increasing laser power increases ODMR contrast, consistent with a power-dependent increase in spin-polarization. Conversely, in nanodiamonds we observe a non-monotonic behavior, with a decrease in ODMR contrast at higher laser power. We hypothesize that this phenomenon may be ascribed to more efficient NV−→NV0 photoconversion in nanodiamonds compared to bulk diamond, resulting in depletion of the NV− pool. A similar behavior is shown for NDs internalized in macrophage cells under the typical experimental conditions of imaging bioassays. Our results suggest strong laser irradiation is not an effective strategy in NDs, where the interplay between surface effects and local microenvironment determine the optimal experimental conditions.

Using the phase-space formulation of quantum mechanics, we derive a four-component Wigner equation for a system composed of spin- fermions (typically, electrons) including the Zeeman effect and the spin–orbit coupling. This Wigner equation is coupled to the appropriate Maxwell equations to form a self-consistent mean-field model. A set of semiclassical Vlasov equations with spin effects is obtained by expanding the full quantum model to first order in the Planck constant. The corresponding hydrodynamic equations are derived by taking velocity moments of the phase-space distribution function. A simple closure relation is proposed to obtain a closed set of hydrodynamic equations. This article is part of the themed issue ‘Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces’.

Semiconductor detectors for high-energy sensing (X/γ-rays) play a critical role in fields such as astronomy, particle physics, spectroscopy, medical imaging, and homeland security. The increasing need for precise detector characterization highlights the importance of developing advanced digital twins, which help optimize the design and performance of imaging systems. Current simulation frameworks primarily focus on modeling electron–hole pair dynamics within the semiconductor bulk after the photon absorption, leading to the current signals at the nearby electrodes. However, most simulations neglect charge diffusion and Coulomb repulsion, which spatially expand the charge cloud during propagation due to the high complexity they add to the physical models. Although these effects are relatively weak, their inclusion is essential for achieving a high-fidelity replication of real detector behavior. There are some existing methods that successfully incorporate these two phenomena with minimal computational cost, including those developed by Gatti in 1987 and by Benoit and Hamel in 2009. The present work evaluates these two approaches and proposes a novel Monte Carlo technique that offers higher accuracy in exchange for increased computational time. Our new method enables more realistic performance predictions while remaining within practical computational limits.

Four-dimensional scanning ultrafast electron microscopy is used to investigate doping- and carrier-concentration-dependent ultrafast carrier dynamics of the in situ cleaved single-crystalline GaAs(110) substrates. We observed marked changes in the measured time-resolved secondary electrons depending on the induced alterations in the electronic structure. The enhancement of secondary electrons at positive times, when the electron pulse follows the optical pulse, is primarily due to an energy gain involving the photoexcited charge carriers that are transiently populated in the conduction band and further promoted by the electron pulse, consistent with a band structure that is dependent on chemical doping and carrier concentration. When electrons undergo sufficient energy loss on their journey to the surface, dark contrast becomes dominant in the image. At negative times, however, when the electron pulse precedes the optical pulse (electron impact), the dynamical behavior of carriers manifests itself in a dark contrast which indicates the suppression of secondary electrons upon the arrival of the optical pulse. In this case, the loss of energy of material’s electrons is by collisions with the excited carriers. These results for carrier dynamics in GaAs(110) suggest strong carrier–carrier scatterings which are mirrored in the energy of material’s secondary electrons during their migration to the surface. The approach presented here provides a fundamental understanding of materials probed by four-dimensional scanning ultrafast electron microscopy, and offers possibilities for use of this imaging technique in the study of ultrafast charge carrier dynamics in heterogeneously patterned micro- and nanostructured material surfaces and interfaces.

The emerging field of spinoptronics has a potential to supersede the functionality of modern electronics, while a proper description of strong light-matter coupling pose the most intriguing questions from both fundamental scientific and technological perspectives. In this paper we address a highly relevant issue for such a development. We theoretically explore spin dynamics on the surface of a 3D topological insulator (TI) irradiated with an off-resonant high-frequency electromagnetic wave. The strong coupling between electrons and the electromagnetic wave drastically modifies the spin properties of TI. The effects of irradiation are shown to result in anisotropy of electron energy spectrum near the Dirac point and suppression of spin current and are investigated in detail in this work.