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The unique structure of van der Waals materials facilitates a robust mechanism for precise control of physical properties. In this study, we present a comprehensive analysis based on the intercalation of organometallics to modulate the optoelectronic behavior of two-dimensional germanium sulfide (GeS). Advanced computational exploration reveals significant and tunable features in the intercalated material. Additionally, the weak chemical interactions between organometallics and GeS support the electric-field-mediated drift and charge–discharge processes in intercalants. Controlling the concentration of organometallics in this manner enables the dynamic emergence of novel characteristics post-intercalation. These include flatbands near the Fermi level, significant enhancement of carrier mobility, and a magnetic ground state that is atypical for pristine GeS. Our findings demonstrate that organometallic intercalation offers a powerful strategy for tailoring the optoelectronic and magnetic characteristics of GeS, paving the way for harnessing emerging features for applications in next-generation devices. [ABSTRACT FROM AUTHOR]

The two-dimensional (2D) Ruddlesden−Popper phase all-inorganic halide perovskite Cs2PbI2Cl2 has attracted tremendous attention because of its high carrier mobility, strong light-absorbing ability, and excellent environmental stability, possessing enormous potential for use as a high-performance optoelectronic device. Here, we present two transistor devices based on monolayer (ML) Cs2PbI2Cl2 and reveal their performance and current transport mechanisms through ab initio quantum transport calculations. The n-type 10 nm metal-oxide-semiconductor field-effect transistor shows a high on-state current Ion of 3160 μA/μm, and excellent performance regarding subthreshold swing, intrinsic delay time (τ), and power consumption, which completely match the International Roadmap for Device and Systems (2021 version) targets for high-performance devices and low-power devices in 2028. Moreover, phototransistors based on monolayer Cs2PbI2Cl2 also display a strong response to UV light, with a light-to-dark current ratio reaching a maximum of 104. Meanwhile, a high specific detectivity of 2.45 × 1011 Jones is obtained. The results of our study suggest that ML Cs2PbI2Cl2 is a promising candidate for high-performance transistors. [ABSTRACT FROM AUTHOR]

β-(AlxGa1−x)2O3 presents a diverse material characterization exhibiting exceptional electrical and optical properties. Considering the miniaturization of gallium oxide devices, two-dimensional (AlxGa1−x)2O3 alloys, as a critical component in the formation of two-dimensional electron gases, demand an in-depth examination of their carrier transport properties. Herein, we investigate the temperature-dependent carrier mobility and scattering mechanisms of quasi-two-dimensional (2D) (AlxGa1−x)2O3 (x ≤ 5) by solving the Boltzmann transport equation from first-principles. Anisotropic electron mobility of 2D (AlxGa1−x)2O3 is limited to 30−80 cm2/Vs at room temperature, and it finds that the relatively large ion-clamped dielectric tensors (Δɛ) suggest a major scattering role for polar optical phonons. The mobility of 2D (AlxGa1−x)2 is less than that of bulk β-(AlxGa1−x)2O3 and shows no quantum effects attributed to the dangling bonds on the surface. We further demonstrate that the bandgap of 2D (AlxGa1−x)2O3 decreases with the number of layers, and the electron localization function also shows an anisotropy. This work comprehensively interprets the scattering mechanism and unintentional doping intrinsic electron mobility of (AlxGa1−x)2O3 alloys, providing physical elaboration and alternative horizons for experimental synthesis, crystallographic investigations, and power device fabrication of 2D (AlxGa1−x)2O3 atomically thin layered systems. [ABSTRACT FROM AUTHOR]

Understanding excited-state intramolecular proton transfer (ESIPT) is essential for designing organic molecules to enhance photophysical and luminophore properties in the development of optoelectronic devices. In this context, an attempt has been made to understand the impact of substituents on the ESIPT process of 2-(oxazolinyl)-phenol. Electron donating (EDG: –NH2, –OCH3, and –CH3) and electron withdrawing (EWG: –Cl, –Br, –COOH, –CF3, –CN, and –NO2) substitutions have been computationally designed and screened through density functional theory (DFT) and time-dependent density-functional theory (TDDFT) calculations. Furthermore, the ground state intramolecular proton transfer and ESIPT mechanisms of these designed luminophores are explored using the transition state theory. The results reveal that molecules with EDG show higher absorption and emission peaks than molecules with EWG and also indicate that the mobility of charge carriers in 2-(oxazolinyl)-phenol derivatives is significantly influenced by substituents. We found that the EWGs decrease the reorganization energy and increase the vertical ionization potential and electron affinity values, as well as the highest occupied molecular orbital-lowest unoccupied molecular orbital gap, compared to the EDG substituted molecules. Significantly, the excited state (S1) of the keto emission (K) form shows notably larger values for the EDG substitutions. The intersystem crossing pathway efficiency weakens with reduced spin–orbit coupling matrix element in the enol form with electron-donating substituents and vice versa in the keto form during S1–T3 transitions. Our research links intramolecular proton transfers and triplet generation, making these substituted molecules appealing for optoelectronic devices. Introducing EDGs, such as –NH2, boosts the ESIPT reaction in 2-(oxazolinyl)-phenol. This study guides designing ESIPT emitters with unique photophysical properties. [ABSTRACT FROM AUTHOR]

In recent years, inorganic lead-free perovskite materials have garnered attention for their non-toxicity, high carrier mobility, and strong light absorption capabilities, showing promising application prospects in photoelectric sensing. CsCu2I3 perovskite has been mentioned as one of the representatives and as a potential material for short-wavelength optoelectronic devices. This study employs a one-step chemical vapor deposition (CVD) process to fabricate CsCu2I3 thin films, which exhibit a vibrant yellow emission at 560 nm. Ultraviolet photodetectors utilizing CsCu2I3 films demonstrate an exceptional responsivity and a detectivity of 1.43 A/W and 1.15 × 1012 Jones (254 nm, 5 V bias), along with rapid response times (trise ≈ 50 ms, tdecay ≈ 70 ms). Moreover, this work examines the factors affecting device performance, including wavelength, operating voltage, and film thickness. It presents a straightforward, ecofriendly CVD method for producing lead-free perovskite films and optoelectronic devices, which has significant implications for the development of lead-free perovskite-based photoelectric technologies. [ABSTRACT FROM AUTHOR]

We present a comprehensive analysis of the structure–property relationship in small molecule non-fullerene acceptors (NFAs) featuring an acceptor–donor–acceptor configuration employing state-of-the-art quantum chemical computational methods. Our focus lies in the strategic functionalization of halogen groups at the terminal positions of NFAs as an effective means to mitigate non-radiative voltage losses and augment photovoltaic and photophysical properties relevant to organic solar cells. Through photophysical studies, we observe a bathochromic shift in the visible region for all halogen-functionalized NFAs, except type-2, compared to the unmodified compound. Most of these functionalized compounds exhibit exciton binding energies below 0.3 eV and ΔLUMO less than 0.3 eV, indicating their potential as promising candidates for organic solar cells. Selected candidate structures undergo an analysis of charge transport properties using the semi-classical Marcus theory based on hopping transport formalism. Molecular dynamics simulations followed by charge transport simulations reveal an ambipolar nature of charge transport in the investigated NFAs, with equivalent hole and electron mobilities compared to the parent compound. Our findings underscore the crucial role of end-group functionalization in enhancing the photovoltaic and photophysical characteristics of NFAs, ultimately improving the overall performance of organic solar cells. This study advances our understanding of the structure–property relationships in NFAs and provides valuable insights into the design and optimization of organic solar cell materials. [ABSTRACT FROM AUTHOR]

Charge carrier mobility and recombination determine the performance of many opto-electronic devices such as solar cells, sensors, and light-emitting diodes. Understanding how these parameters change as a function of material choice, charge carrier density, and device geometry is essential for developing the next generation of devices. The time-delayed collection field (TDCF) technique is becoming a widely used method to measure both recombination and carrier transport with values derived from this method being widely reported for many material systems. However, most novel materials are highly disordered with a high density of trap states and standard TDCF theory neglects the influence of these states. In this work, we examine how reliable TDCF can be as a measurement technique when the device contains significant energetic disorder. We identify regimes where the results can be relied upon and where the results should be taken with more caution. Finally, we provide simple and easy to use experimental tests to help the experimentalist decide whether the physical processes are dominated by trap states. [ABSTRACT FROM AUTHOR]

We report the topology-mediated modulation of a twisted domain wall speed in a thick perpendicularly magnetized system. By exploiting the topological robustness of the direction of the Bloch wall component in the twisted domain wall, we show that the domain wall speed either increases or decreases depending on whether the transverse magnetic field is parallel or antiparallel to the Bloch wall component. The decrease in the speed is maintained until the antiparallel transverse reaches ∼0.3 T, indicating that the twisted domain wall can offer wide controllability supported by the topological robustness which involves an injection of a Bloch point. We also demonstrate that the transverse magnetic field suppresses the Walker breakdown, allowing high mobility domain wall motion for a wide range of perpendicular driving fields. [ABSTRACT FROM AUTHOR]

The mesmerizing physical properties of two-dimensional (2D) nanomaterials have resulted in their enormous potential for high-power solar energy conversion and long-term stability devices. The present work systematically investigated the fundamental properties of monolayered 2D group-IV–V materials using a combined approach of first-principles calculations and Boltzmann transport theory, specifically the thermoelectric and optical properties, for the first time. The structural and lattice dynamics analysis disclosed the energetic, dynamical, and mechanical stabilities of 17 out of 25 considered materials. The electronic properties' calculation shows that all the stable materials exhibit a semiconducting nature. Additionally, the energy–momentum relation in a few systems reveals the quartic Mexican-hat-like dispersion in their valence band edges. Owing to the larger depth of Mexican-hat dispersion and the larger height of density step function modes, the hole carrier mobilities of SnN (761.43 m2/Vs), GeN (422.80 m2/Vs), and SiN (108.90 m2/Vs) materials were found to be significantly higher than their electron mobilities at room temperature. The achieved high Seebeck coefficient and electrical conductivity at room temperature result in excellent thermoelectric power factors for GeN (3190 mW/mK2), SiN (1473 mW/mK2), and CAs (774 mW/mK2) materials, manifesting their potential for thermoelectric devices. Further, the calculated optical and solar parameters demonstrate an exceptionally high value (27.25%) of theoretical limits of power conversion efficiency for the SnBi material, making it a suitable candidate as a light-absorbing material in solar cell devices. The present theoretical work filters out the potential 2D group-IV–V materials for solar and heat energy-harvesting devices. [ABSTRACT FROM AUTHOR]

A successful hexagonal Cu 2 S p-type semiconductor thin film using DC magnetron sputtering is reported. Films with thickness gradients were deposited by taking advantage of deposition geometry and target dimensions. X-ray diffraction (XRD) analysis confirmed the exclusive formation of the hexagonal Cu 2 S phase. Elemental composition and thickness dependence with the sample position were determined using energy-dispersive x-ray spectroscopy. Optical properties, including the optical bandgap, refractive index, and extinction coefficient, were assessed by modeling transmittance spectra. The Tauc–Lorentz oscillator and Drude models were employed for this purpose. XRD data analysis successfully determined the film thickness (t X R D ) as a function of the sample position, aligning well with thickness values (t T) derived from transmittance spectra analyses. These results were further supported by film thickness values (t S E M ) obtained from cross-sectional SEM images. Charge carrier density and mobility, extracted from the optical models, were found to be consistent with DC electrical measurements. AC impedance curves were effectively modeled with RL–RC parallel circuits. The results indicate that the inductance (L) and capacitance (C) components of the films increase with decreasing film thickness. [ABSTRACT FROM AUTHOR]

Inquiring the isotopically engineered carrier transport in polar materials remains an open question. Herein, the phonon-limited drift carrier mobility of single-crystal cubic boron nitride is presented using first-principles calculations. Natural c-BN has the predicted electron mobility of 1230 and 760 cm2/V s by solving the iterative Boltzmann transport equation and self-energy relaxation time approximation, respectively. The hole mobility under the Boltzmann transport equation and self-energy relaxation time approximation is 193 and 105 cm2/Vs, respectively. Subsequently, the electron and hole mobilities at the stable isotope levels of boron and nitride are predicted, and nitride isotopes are found to be more effective than boron for carrier mobility. Those carrier mobilities further decrease with increasing temperature due to the strengthened electron–phonon interactions. Moreover, the phonon-assisted indirect optical absorption of c-BN is investigated by considering the contribution of phonons to the indirect electronic inter-band transitions. The predicted imaginary part of the dielectric function is in better agreement with previous experiments. This work aims to understand the role of phonons in determining the carrier mobility and indirect optical absorption of c-BN. [ABSTRACT FROM AUTHOR]

The band-anticrossing (BAC) model provides the basis for the self-consistent Green's function method that we have previously developed to calculate the density of states of GaN x As 1 − x dilute nitride alloys. In this paper, we extend this Green's function method to include the complex energy states and to find the poles of the Green's function, thereby allowing one to calculate the dispersion relation, group velocity, and the carrier decay rate in disordered dilute nitride alloys. Two different models of the N states have been studied to investigate the band structure of these materials: (1) the conventional two-band BAC model, which assumes that all N states are located at the same energy, and (2) a model which includes N states distributed over a range of energies, as expected in actual dilute nitride samples. Our results for the second model show a much shorter carrier mean-free path, and lower carrier mobility for GaN x As 1 − x , with the magnitude of the calculated mobility in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

The ability to spatially resolve the carrier mobility profile along the cross section of micrometer-thin solar cells is vital, both for fundamental studies in photovoltaics and as quality control for reproducibly obtaining high conversion efficiencies in commercial solar cell modules. Presently, no technique capable of such an endeavor is available to the best of our knowledge. Here, we introduce a novel method capable of profiling the carrier mobility along the z axis in thin-film photovoltaics. Our setup is based on the integration of photogenerated charge extraction by linearly increasing voltage (p-CELIV) with a scanning confocal optical microscope (SCOM) toward a confocal and cross-sectional p-CELIV (cs-p-CELIV) system. As monomolecular recombination of excess carriers is the most frequent radiative pathway for electrons and holes in solar cells at low power density of illumination, while multimolecular recombination dominates at high power, enhanced multimolecular recombination occurs at the SCOM focal plane. Thus, the cs-p-CELIV signal provides enhanced information on the mobility of all of the cross-sectional layers except the focal plane. By scanning the focal plane along the z axis, the mobility profile can be derived. To demonstrate our technique, we use it to investigate the carrier mobility in three hydrogenated amorphous silicon (a-Si:H) solar cells. The mobility profiles obtained by cs-p-CELIV correlate well with well-known depletion layer effects and the H content profile in a-Si:H, which is measured independently. Our findings are in excellent agreement with models suggesting a critical role of Si–H bonding in locally determining the carrier mobility in a-Si:H. [ABSTRACT FROM AUTHOR]

The semiconductor/insulator blends for organic field-effect transistors are a potential solution to improve the charge transport in the active layer by inducing phase separation in the blends. However, the technique is less investigated for long-chain conducting polymers such as Poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b]thiophene)] (DPPDTT), and lateral phase separation is generally reported due to the instability during solvent evaporation, which results in degraded device performance. Herein, we report how to tailor the dominant mechanism of phase separation in such blends and the molecular assembly of the polymer. For DPPDTT/PMMA blends, we found that for higher DPPDTT concentrations (more than 75%) where the vertical phase separation mechanism is dominant, PMMA assisted in the self-assembly of DPPDTT to form nanowires and micro-transport channels on top of PMMA. The formation of nanowires yielded 13 times higher mobility as compared to pristine devices. For blend ratios with DPPDTT ≤ 50%, both the competing mechanisms, vertical and lateral phase separation, are taking place. It resulted in somewhat lower charge carrier mobilities. Hence, our results show that by systematic tuning of the blend ratio, PMMA can act as an excellent binding material in long-chain polymers such as DPPDTT and produce vertically stratified and aligned structures to ensure high mobility devices. [ABSTRACT FROM AUTHOR]

The delafossite semiconductor CuInO 2 has shown great potential in transparent electronics for its bipolar dopability. However, little is known about the limiting factors about its carrier mobility, which impedes its further development. Applying a b i n i t i o Boltzmann transport formalism, here we calculate the intrinsic, phonon-limited carrier mobility of CuInO 2 and study its carrier–phonon coupling mechanisms. The calculated room-temperature electron and hole mobilities along the in-plane direction are μ e = 97.6 cm 2 V − 1 s − 1 and μ h = 1.4 cm 2 V − 1 s − 1 , respectively. We find that the electron mobility is limited by the combination of acoustic phonons and polar longitudinal optical (LO) phonons, while the hole mobility is mainly limited by carrier–acoustic phonon scattering. We further show that the electron effective mass and bandgap of CuInO 2 can be tuned through strain engineering for improved carrier transport properties. Our work uncovers the underlying factors that govern the intrinsic carrier mobility of the transparent bipolar semiconductor CuInO 2 and sheds light on the design and exploration of bipolar conducting transparent conductive oxides (TCOs) based on delafossite semiconductors. [ABSTRACT FROM AUTHOR]

The delafossite semiconductor CuInO 2 has shown great potential in transparent electronics for its bipolar dopability. However, little is known about the limiting factors about its carrier mobility, which impedes its further development. Applying a b i n i t i o Boltzmann transport formalism, here we calculate the intrinsic, phonon-limited carrier mobility of CuInO 2 and study its carrier–phonon coupling mechanisms. The calculated room-temperature electron and hole mobilities along the in-plane direction are μ e = 97.6 cm 2 V − 1 s − 1 and μ h = 1.4 cm 2 V − 1 s − 1 , respectively. We find that the electron mobility is limited by the combination of acoustic phonons and polar longitudinal optical (LO) phonons, while the hole mobility is mainly limited by carrier–acoustic phonon scattering. We further show that the electron effective mass and bandgap of CuInO 2 can be tuned through strain engineering for improved carrier transport properties. Our work uncovers the underlying factors that govern the intrinsic carrier mobility of the transparent bipolar semiconductor CuInO 2 and sheds light on the design and exploration of bipolar conducting transparent conductive oxides (TCOs) based on delafossite semiconductors. [ABSTRACT FROM AUTHOR]

The aim of this study is to suggest a novel approach for estimating the intramolecular mobility of a charge carrier that migrates within a polymer chain and is involved in a pair reaction with a particle located on the same chain. The approach is based on the effect of an external electric field on the migration rate and, consequently, the kinetics of the reaction. As a first step, this problem is considered a stochastic one-step process with absorbing and reflecting boundaries, and an analytical solution is obtained in the case that the second reactant is immobile. With the use of computer simulations of stochastic migration, the effect of the mobility of both reactants and the influence of the Coulomb interaction between them are considered. It is found that the ratio of the pair reaction rates with and without an external field is relatively little dependent on these factors and that the analytical expressions derived can be applied to estimate the relative mobility of recombining particles with accuracy better than a factor of two in many realistic situations. [ABSTRACT FROM AUTHOR]

Interband recombination in bulk indium-rich InGaN is studied via both spontaneous and stimulated emissions. Based on the low-temperature luminescence and absorption data, the magnitude of the edge tails in conduction and valence bands is determined, and the non-thermal energy distribution of excess holes localized in the fluctuating band potential is revealed. We show that the combination of carrier localization effects and Auger-determined interband rates fully accounts for the experimentally observed stimulated emission thresholds and gain values (∼20–30 kW/cm2 and >100 cm−1, respectively) at low temperatures (T < 100 K). It is suggested that exploiting structural disorder to keep injected holes below the mobility edge, thus suppressing defect-related recombination, is a prerequisite for high-temperature infrared lasing from degenerate InGaN with relatively temperature-stable threshold intensities of some 100 kW/cm2. [ABSTRACT FROM AUTHOR]

As the channel lengths of electronic devices are scaled down to the nanometer range, the conventional methods to evaluate charge-carrier mobility approach a technical limit that is imposed by interfering effects of the electrode and forcing field. In this study, we demonstrate that electron spectroscopy provides additional (yet hidden) information on unipolar charge transport, which is free from conventional problems. We demonstrate that the estimated effective diffusion current through the target sample allows the measurement that is precise enough (10−4 cm2/V s) to obtain the mobility of electrons μelectron and holes μhole in nanolength organic channels. Using this method, we show how μelectron and μhole are correlated with the local structural order of poly(3-hexylthiophene) at the nanoscale. This method enables in situ charge-resolved observations of μelectron and μhole by eliminating the need for electrode and forcing field and will help to expand our understanding of charge conduction in nanoscale materials. [ABSTRACT FROM AUTHOR]

Periodic density functional theory was employed to investigate the impact of chemical modifications on the properties of π-conjugated acenedithiophene molecular crystals. Here, we highlight the importance of the β-methylthionation effect, the position of the sulfur atoms of the thiacycle group and their size, and the number of central benzene rings in the chemical modification strategy. Our results show that the introduction of the methylthio groups at the β-positions of the thiophene and the additional benzene ring at the center of the BDT crystal structure are a promising strategy to improve the performance of organic semiconductors, as observed experimentally. We found that β-MT-ADT exhibits large charge carrier mobility, which is in good agreement with the experimental results and comparable to that of rubrene. In addition, the electronic and optical properties of these ambipolar materials suggest promising performances with β-MT-ADT > ADT > β -MT-NDT > NDT > BEDT-BDT > β -MT-BDT > BDT. Moreover, functionalization with thiacycle-fused sulfur atoms of different sizes and numbers improve the properties of BDT but is still less efficient than the methylthionation effect. Overall, our findings suggest a promising molecular modification strategy for possibly high performance ambipolar organic semiconducting materials. [ABSTRACT FROM AUTHOR]

Understanding and modulating the spin-pair correlation of conjugated polymer materials in π-conjugated polymer light-emitting devices (PLEDs) plays a crucial role in the development of their applications. We investigated the relationships between the internal hyperfine interactions (HFIs), triplet–triplet annihilation (TTA), and triplet–charge annihilation (TCA) spin evolution processes in π-conjugated PLED. Research has shown that in a unipolar π-conjugated PLED, the "M" shaped ultra-small magnetic field effect is due to the HFI between hole polarons and the spin-mixing process of charge carriers. Under high magnetic fields (15 mT<|B|<350 mT), the TCA process dominates the negative magneto-conductance (MC), and its intensity and sign are not controlled by temperature. In polar π-conjugated PLED, excess carriers can provide conditions for the generation of TCA. Moreover, π-conjugated polymers (emission layers) have relatively strong electron–phonon coupling, which can capture triplet excitons into adjacent organic layers to obtain higher triplet exciton concentrations, resulting in the TTA process. Under low-temperature conditions, excess carriers induce the magneto-electroluminescence (MEL) effect to undergo TTA and form P-type delayed fluorescence. This study can provide a new mechanism explanation for the HFI in PLED devices and a new approach for the effective utilization of triplets. [ABSTRACT FROM AUTHOR]

The lead halide perovskites have emerged as promising materials with intriguing photo-physical properties and have immense potential for photovoltaic applications. A comprehensive study on the kinetics of charge carrier (electron/hole) generation and transfer across the interface is key to realizing their future scope for efficient device engineering. Herein, we investigate the interfacial charge transfer (CT) dynamics in cesium lead halide (CsPbBr3) perovskite quantum dots (PQDs) with energetically favorable electron acceptors, anthraquinone (AQ) and p-benzoquinone (BQ), and hole acceptors such as pyrene and 4-(dimethylamino)pyridine (DMAP). With various steady-state and time-resolved spectroscopic and microscopic measurements, a faster electron transfer rate is estimated for CsPbBr3 PQDs with BQ compared to that of AQ, while a superior hole transfer for DMAP is divulged compared to pyrene. In concurrence with the spectroscopic measurements, conducting atomic force microscopic studies across the electrode-PQD-electrode junction reveals an increment in the conductance of the PQD in the presence of both the electron and hole acceptors. The variation of the density of states calculation in the presence of the hole acceptors offers strong support and validation for faster CT efficiency. The above findings suggest that a careful selection of simple yet efficient molecular arrangements can facilitate rapid carrier transfer, which can be designed as auxiliary layers for smooth CT and help in the engineering of cost-effective photovoltaic devices. [ABSTRACT FROM AUTHOR]

Two-dimensional transition metal chalcogenides (2D TMCs) like MoS2, WS2 etc., have established significant dominance in the field of nanoscience and nanotechnology, owing to their unique properties like strong light–matter interaction, high carrier mobility, large photo-responsivity etc. Despite the widespread utilization of these binary TMCs, their potential in the advancement of the optoelectronic research is limited due to the constraints in band tuning and charge carrier lifetime. To overcome these limitations, ternary transition metal chalcogenides have emerged as promising alternatives. Although, the optical properties of these materials have never been explored properly. Herein, we have investigated one such promising member of this group, Cu2MoS4 (CMS) using both steady state and time-resolved spectroscopic techniques. The material exhibits a broad range of visible light absorption, peaking at 576 nm. Photoluminescence spectroscopy confirmed the presence of both band gap emission and trap state-mediated emissions. Transient absorption spectroscopy unraveled the excited state charge carrier dynamics of CMS in sub-ps timescale, upon irradiation of visible light. We found significant influence of the trap mediated recombination, while Auger process being dominant at high charge density. We extended our study in a wide temperature range (5–300 K), which reveals the impact of electron-phonon coupling strength on the band gap and charge carrier dynamics of this material. This detailed study would draw more attention toward the unexplored optical properties of ternary 2D chalcogenides and will open new avenues for the construction of 2D material-based optical devices. [ABSTRACT FROM AUTHOR]

Spin gapless semiconductor (SGS) has attracted much attention since its theoretical prediction, while concrete experimental hints are still lacking in the relevant Heusler alloys. Here in this work, by preparing the series alloys of Mn2CoGa1−xAlx (x = 0, 0.25, 0.5, 0.75, and 1), we identified the vanishing of the anomalous Hall effect in the ferromagnetic Mn2CoGa (or x = 0.25) alloy in a wide temperature interval, accompanying with growing contribution from the ordinary Hall effect. As a result, comparatively low carrier density (1020 cm−3) and high carrier mobility (150 cm2/V s) are obtained in the Mn2CoGa (or x = 0.25) alloy in the temperature range of 10–200 K. These also lead to a large dip in the related magnetoresistance at low fields. However, in a high Al content, although the magnetization behavior is not altered significantly, the Hall resistivity is, instead, dominated by the anomalous one, just analogous to that widely reported in Mn2CoAl. The distinct electrical-transport behavior of x = 0 and x = 0.75 (or 1) is presently understood by their possible different scattering mechanism of the anomalous Hall effect due to the differences in the atomic order and conductivity. Our work can expand the existing understanding of the SGS properties and offer a better SGS candidate with higher carrier mobility that can facilitate the application in the spin-injected related devices. [ABSTRACT FROM AUTHOR]

We numerically examine the driven transport of an overdamped self-propelled particle through a two-dimensional array of circular obstacles. A detailed analysis of transport quantifiers (mobility and diffusivity) has been performed for two types of channels, channel I and channel II, that respectively correspond to the parallel and diagonal drives with respect to the array axis. Our simulation results show that the signatures of pinning actions and depinning processes in the array of obstacles are manifested through excess diffusion peaks or sudden drops in diffusivity, and abrupt jumps in mobility with varying amplitude of the drive. The underlying depinning mechanisms and the associated threshold driving strength largely depend on the persistent length of self-propulsion. For low driving strength, both diffusivity and mobility are noticeably suppressed by the array of obstacles, irrespective of the self-propulsion parameters and direction of the drive. When self-propulsion length is larger than a channel compartment size, transport quantifiers are insensitive to the rotational relaxation time. Transport with diagonal drives features self-propulsion-dependent negative differential mobility. The amplitude of the negative differential mobility of an active particle is much larger than that of a passive one. The present analysis aims at understanding the driven transport of active species like, bacteria, virus, Janus particle etc. in porous medium. [ABSTRACT FROM AUTHOR]

The characteristic polytype behaviors of SiC and accompanying low stacking fault energies are known to cause engineering issues, including polytype inclusions and bipolar degradation. The dependence of the relative stability of SiC polytypes and stacking fault energies on excess carrier concentration was investigated using first-principles calculations. The relative energy of 2H-, 4H-, and 6H-SiC to 3C-SiC increased with the excess electrons over 2 × 1019 cm−3, while the energy variation with excess holes was small. The stacking fault energies in 4H-SiC also exhibited a significant decrease with excess electrons over 1.0 × 1019 cm−3, whereas this change was minor with excess holes. These excess carrier dependencies were attributed to variations in the bandgap between polytypes. The energy level of the excess electrons was at the conduction band minimum; this was lowest in 3C-SiC, which had the lowest bandgap energy. Consequently, the energy of 3C-SiC with excess electrons was lower than that of other polytypes. Conversely, the valence band maximum lacked electrons when excess holes were present, resulting in a small difference among the Fermi levels of the polytypes. Hence, the energy difference between the SiC polytypes was similar for excess holes. Similarly, the stacking faults in SiC exhibited quantum-well structures by incorporating other polytypes with different bandgaps. With excess electrons, the Fermi level within the stacking faults was lower than that in the bulk crystals. Consequently, the stacking fault energy decreased for the same reason that the energy in 3C-SiC decreased under excess electron conditions. [ABSTRACT FROM AUTHOR]

Monolayer HfSe2, in the family of transition metal dichalcogenides (TMDCs), is a potential thermoelectric candidate due to its low thermal conductivity. While its mobility remains low as in other 2D TMDCs is inconceivable for electronic and thermoelectric applications. Earlier theoretical attempts have failed to give justification for the orders of low experimental mobility obtained for monolayer HfSe2. We calculate the carrier mobility in the framework of the density functional perturbation theory in conjunction with the Boltzmann transport equation and correctly ascertain the experimental value. We also calculate the carrier mobility with the previously employed method, the deformation potential (DP) model, to figure out the reason for its failure. We found that it is the strong electron-optical phonon interaction that is causing the low mobility. As the DP model does not account for the optical phonons, it overestimates the relaxation time by an order of two and also underestimates the temperature dependence of mobility. A strong polar type interaction is evidenced as a manifestation of a discontinuity in the first derivative of the optical-phonons at the K and Γ points as well as a dispersive optical phonon at the K point. We also included the spin–orbit coupling which leads to an energy splitting of ∼330 meV and significantly affects mobility and scattering rates. [ABSTRACT FROM AUTHOR]

Cd2+ cation doped CsPbCl3 single crystals were synthesized, and their luminescent properties were investigated under excitation with synchrotron radiation quanta with energy greater than Eg and at a sample temperature of 12 K. Pure single crystals exhibit a narrow band of exciton emission at 416.7 nm. Doping the single crystals leads to a high-energy shift of the excitonic luminescence, the appearance of new luminescent bands, the broadening of the luminescent bands, an increase in the decay time constants, and a significant enhancement of the luminescence intensity. The observed changes in luminescent parameters upon doping are discussed in terms of the crystal structure ordering, a decrease in the number of defects responsible for capturing charge carriers at the stage of electronic excitation thermalization, and a decrease in defects that quench excitonic luminescence. Doped single crystals with decay times of the order of 0.4 ns and intensities that significantly exceed the intensity of pure single crystals can be promising scintillation materials for positron emission tomography in the time-of-flight mode. [ABSTRACT FROM AUTHOR]

The lattice mismatch, defect, and weak interlayer coupling severely constrain the practical application of van der Waals heterojunctions (vdWHs) in the field of optoelectronic devices. Here, we introduced the 2D ferroelectric (FE) material AgBiP2Se6 to construct defect-free, low lattice-mismatched AgBiP2Se6/MoSe2 heterojunctions with different polariton directions (I, II, III). The AgBiP2Se6 layer can provide an excellent FE electric field to enhance the interlayer coupling and stiffness. The larger interlay stiffness reduces the probability of electron–phonon scattering and then results in significant carrier mobility (∼0.5 × 104 cm2 V−1 s−1) for configurations I and II. Phase transition of FE to paraelectric AgBiP2Se6 in the AgBiP2Se6/MoSe2 heterojunctions can be achieved under specific biaxial strain, which can effectively regulate the electronic structure. Applying the strain and electric field can regulate the bandgap and band alignment of configurations I and II. The photoelectric conversion efficiency of configuration I can reach as high as 20.54% under 2% biaxial strain. Furthermore, configuration II holds a nearly free electron state near the Fermi level under an electric field, which can act as a favorable electron transport channel. A design to strengthen interlayer coupling in the FE-based AgBiP2Se6/MoSe2 heterojunction has been proposed, and it can provide a new way to break through the traditional bottleneck in the development of optoelectronic devices. [ABSTRACT FROM AUTHOR]

Chiral materials exhibit many interesting physical properties including circular dichroism, circularly polarized photoluminescence, and spin selectivity. Since its discovery, chirality-induced spin selectivity (CISS) has been demonstrated in many chiral material systems, which indicates promising applications in spintronic devices. Thus, searching for compounds that possess both sizable chirality and excellent spin transport properties is in order. Hybrid organic–inorganic perovskites have attracted intensive research interest due to their long carrier lifetime, high carrier mobility, chemically tunable electronic properties, and long spin lifetime, which make this emerging class of semiconductors promising candidate for spintronics. Moreover, hybrid perovskites integrate inorganic octahedral framework and organic ligands, which may introduce chirality into the materials, especially in quasi-two-dimensional structures. Recently, CISS has been observed in 2D chiral hybrid perovskites, showing the spin filtering effect. Studies of CISS in chiral hybrid perovskites not only help deepen our understanding of CISS mechanism but also shed new light on designing novel spintronic devices. In this review, we summarize the state-of-the-art studies of CISS effect in 2D chiral hybrid organic–inorganic perovskites system. We also discuss the remaining challenges and research opportunities of employing CISS in next-generation spintronic devices. [ABSTRACT FROM AUTHOR]

g-C 3 N 4 is a promising metal-free photocatalyst for hydrogen production, whose application is difficult due to the low mobility of charge carriers and rapid electron-hole recombination. Here we propose a new route to improve its response to simulated sunlight and prevent electron-hole recombination by grafting mixed Ag–NiO (1:1 nominal Ag/NiO weight ratio) materials, as an alternative to platinum group metal co-catalysts. g-C 3 N 4 was prepared by urea pyrolysis, whereas Ag–NiO was prepared by a co-precipitation method, and then the composites were prepared by physical mixing using sonication-grinding. The presence of Ag–NiO on the surface plays a key role in accepting excited electrons and enhancing their lifetime for a subsequent reduction of protons to hydrogen. Hydrogen production was carried out from the photoreforming of ethanol under simulated sunlight. The results revealed that 2% (Ag–NiO)/g-C 3 N 4 is effective among others with 5.2 times higher H 2 production than unmodified g-C 3 N 4. The percentage of ethanol in the ethanol/water ratio is very important as we have found that with increasing its quantity, the evolution of hydrogen becomes significant. • New series of g-C 3 N 4 photocatalysts modified with mixed Ag–NiO. • Innovative synthesis of isolated Ag–NiO and (Ag–NiO)/g-C 3 N 4 composite. • Ag–NiO significantly reduces electron-hole recombination. • The optimal composite is 2% (Ag–NiO)/g-C 3 N 4. • Hydrogen evolution via ethanol photoreforming under simulated sunlight. [ABSTRACT FROM AUTHOR]

MXenes belong to the potential family of two-dimensional materials with distinctive characteristics that make them appealing for various uses, especially in energy storage systems. Exploring two-dimensional (2D) components has expanded beyond graphene, encompassing extreme materials like phosphorene and its derivatives. Notably, the emergence of 2-dimensional titanium carbide (Ti 3 C 2), the pioneering member of the MXene family, offers specific structural and electrical properties conducive to diverse applications. MXenes, derived from selective layer etching through metal nitrides and carbides (MAX phases), exhibit a layered structure akin to graphene and electrical conductivity. With approximately a combination of 30 materials, it has been documented and observed that MXenes hold promise across industries such as Li-ion battery cells (LIBs), super-capacitors, catalysis, and hydrogen storage. This review systematically outlines production techniques, catalyst performance, and potential enhancements in MXene applications. Catalyst production methods yield promising results, with discussions on challenges and proposed solutions. Structural stability and diverse applications of MXenes, including batteries and catalysis, are explored, emphasizing morphological, optical, and electrical characteristics. Future research directions are recommended to address existing challenges and leverage this review as a guidepost for further investigation and advancement in MXene materials science. CuMnO 2 /MXene nanocomposite is a viable option for battery electrode material due to its excellent properties. CuMnO 2 combined oxides will increase the power density by acting as active sites, enhancing charge transportation of charge and rate capability, while MXene will increase electrical conductivity by enhancing cycling stability. This composite will be a promising candidate for positively impacting battery performance. [ABSTRACT FROM AUTHOR]

To minimize bowing in a gallium nitride (GaN) template, which is caused by differences in the properties of the GaN film and the sapphire substrate, we studied how to offset bowing by directly growing GaN using the hydride vapor phase epitaxy (HVPE) method on the frontside of a pre-strained sapphire substrate prepared using a backside grinding process. The relationships between the respective thicknesses and stresses of the undamaged sapphire, damaged sapphire, and GaN layers were analyzed by deriving the bow formula, which is a modification of Freund's equation, and the theoretical formula-derived results were compared with experimentally determined values. The bow of the GaN template was measured using a micrometer, and the residual stresses in the GaN and sapphire, carrier mobilities, and GaN crystal qualities were measured using a micro-Raman spectrophotometer. The results confirmed the annealing effect on the damaged sapphire layer, and the introduction of pre-strained GaN templates facilitated easier bow control compared to that afforded by a conventional GaN template. Additionally, we identified trends and optimal conditions for changes in residual stress, carrier mobility, and crystal quality in GaN and the damaged sapphire layer based on layer thickness and stress variations. We explain the mechanisms responsible for changes in bow, stress, carrier mobility, and crystal quality of the GaN template. [Display omitted] • A pre-strained sapphire was introduced to minimize the bow in the GaN template. • The bow of the pre-strained GaN template was counterbalanced by epitaxial GaN growth. • Relationships between composed layers were interpreted using the induced bow formula. • Residual stress, carrier mobility, and crystallinity trends in GaN were analyzed. • Mechanisms governing bow and optical properties were elucidated. [ABSTRACT FROM AUTHOR]

Pseudo-cubic perovskite La-doped SrSnO 3 has been proposed as a promising alternative for ultra-violet (UV) transparent conductors due to its favorable electrical transport properties and UV transparency. However, the difficulty in fabricating large-size La-doped SrSnO 3 films with high electrical mobility continues to hinder the development of practical applications. In this work, Sr 0.94 La 0.06 SnO 3 (SLSO) thin films with wide bandgap of ∼4.5 eV were fabricated by using solution deposition route. Emphasis was placed on creating oxygen-poor environments and selecting appropriate post-annealing temperatures, which were determined based on the kinetic energy of relevant defects and second-phase impurities. Post-annealing treatment was applied to refine the microstructure and enhance electrical transport properties. As a result, a relatively high carrier mobility of 25.9 cm2 V−1 s−1 and a low resistivity of 1.15 mΩ cm at a carrier concentration of 2.08 × 1020 cm−3 were achieved. Enhanced electrical properties were attributed to the increased presence of oxygen vacancies, as confirmed by electron paramagnetic resonance results. This study presents a straightforward approach for the production of large-scale epitaxial UV transparent conducting SLSO thin films. [ABSTRACT FROM AUTHOR]

Microwave absorption materials have attracted attention due to their extensive applications in different fields. Herein, ytterbium-doped BaCo 2 W-type hexaferrite nanocrystallites with a nominal composition of BaCo 2 Yb x Fe 16−x O 27 (x = 0.00, 0.03, 0.06, 0.09, and 0.12) were synthesized via the sol–gel method, and their physicochemical and dielectric characteristics were estimated. XRD plots revealed the pure phase structure of each prepared hexaferrite sample. The lattice constant and unit cell volume were affected by changes in the Yb concentration. The crystallite size was measured by the Debye–Scherrer formula, revealing intense crystals typically in the 18–33 nm range. FTIR spectroscopy showed multiple absorption bands from 430 to 3000 cm−1, and Raman spectroscopy revealed multiple peaks between 200 and 1000 cm−1, displaying the allocated polyhedra and symmetry. XPS spectroscopy confirmed the existence of all metal ions in the required valence state. The dielectric measurements were evaluated at frequencies from 1 to 6 GHz for all the synthesized compositions, and the material behavior was explained using the Maxwell–Wagner and Koop theories. The conduction mechanism in the hexagonal ferrites was assessed using Cole–Cole analysis. Reflection loss measurements were also conducted: the samples at x = 0.03 and x = 0.12 yielded minimal reflection losses of −60.06 and −51.69 dB at 5.5 GHz, respectively. The results demonstrate the suitability of the samples for use in microwave and high-frequency absorption applications. [ABSTRACT FROM AUTHOR]

There is evidence that magnetism can potentially increase the thermopower of materials, most likely due to magnon scattering, suggesting the incorporation of intrinsic magnetic semiconductors in non-magnetic thermoelectric materials. Here, samples of p-type Bi0.5Sb1.5Te3 with 10 at. % excess Te are ball-milled with varying ratios of the antiferromagnetic semiconductor CrSb (0, 0.125, 0.5, and 1 wt. %) to prepare bulk samples by spark plasma sintering technique. The thermopower of samples containing CrSb is increased due to an increase in the effective mass of the charge carriers, indicating that there is a drag effect originating from the magnetic particles. However, this was at the expense of reduced electrical conductivity caused by reduced charge carrier mobility. While overall only marginal improvements in power factors were observed, these samples exhibited significantly lower thermal conductivity compared to the single-phase material. As a result, a peak zT value of ∼1.4 was achieved at 325 K for the sample with 0.125 wt. % CrSb. These results highlight the potential of incorporating magnetic secondary phases to enhance the thermoelectric performance of materials. [ABSTRACT FROM AUTHOR]

Atomic chalcogen vacancy is the most commonly observed defect category in two dimensional (2D) transition‐metal dichalcogenides, which can be detrimental to the intrinsic properties and device performance. Here a low‐defect density, high‐uniform, wafer‐scale single crystal epitaxial technology by in situ oxygen‐incorporated "growth‐repair" strategy is reported. For the first time, the oxygen‐repairing efficiency on MoS2 monolayers at atomic scale is quantitatively evaluated. The sulfur defect density is greatly reduced from (2.71 ± 0.65) × 1013 down to (4.28 ± 0.27) × 1012 cm−2, which is one order of magnitude lower than reported as‐grown MoS2. Such prominent defect deduction is owing to the kinetically more favorable configuration of oxygen substitution and an increase in sulfur vacancy formation energy around oxygen‐incorporated sites by the first‐principle calculations. Furthermore, the sulfur vacancies induced donor defect states is largely eliminated confirmed by quenched defect‐related emission. The devices exhibit improved carrier mobility by more than three times up to 65.2 cm2 V−1 s−1 and lower Schottky barrier height reduced by half (less than 20 meV), originating from the suppressed Fermi‐level pinning effect from disorder‐induced gap state. The work provides an effective route toward engineering the intrinsic defect density and electronic states through modulating synthesis kinetics of 2D materials. [ABSTRACT FROM AUTHOR]

Borophene, a boron analogue of graphene, is typically metallic, while all bulk boron phases are insulating. Here, we predict by first‐principles calculations that recently synthesized bilayer borophene, being suggested to be composed of two stacked v1/12 sheets, is a semiconductor with a bandgap of 1.13 eV, almost the same as that of silicon. It is shown that the stacking mode between two boron sheets as well as the density and pattern of the interlayer boron‐boron (B─B) bonds are the key factors for opening the bandgap in the otherwise metallic boron sheet. Moreover, the bilayer borophene exhibits electron mobility of 878.6 cm2 V−1 s−1 and a significantly higher optical absorption coefficient in the visible region than silicon. These excellent electronic and optical properties hosted in a two atom‐thick space, together with high thermal and mechanical stability, position the bilayer borophene as a promising nanomaterial for maintaining the miniaturization of electronics. [ABSTRACT FROM AUTHOR]

Developing cathode materials for aqueous zinc‐ion batteries (ZIBs) that offer high capacity, rapid charge–discharge rates, and prolonged cycle life remains a significant challenge. This study explores the use of zipper‐type Bi2O2Se nanoplates modified by selenium vacancy (Vse) modulation, which reduces electron scattering, enhances carrier mobility in [Bi2O2] conducting channels, and decreases coulombic interactions within electrostatic layers. The introduction of Se vacancies facilitates electron transfer from the host to [Bi2O2] channels and reduces scattering in the [Bi2O2] framework, thus improving carrier mobility. These Se‐poor Bi2O2Se nanoplates demonstrate a greater affinity for zinc ions, reduced diffusion barriers, and faster transport kinetics, which enable more efficient Zn‐ion insertion, tripling the electrochemical capacity, improving rate capabilities, and extending cycling life. Enhancements such as reinforced structural integrity and expanded interlayer spaces support a dual Zn‐ion‐driven mechanism involving both insertion and conversion reactions, essential for superior electrochemical storage performance. The results include an impressive discharge/charge capacity of 380.3 mA h g−1 at 0.1 A g−1, a cycle life of up to 10 000 cycles at 5 A g−1, and a current tolerance exceeding 10 A g−1. This research highlights how nano‐ and defect engineering of Bi2O2Se can significantly enhance ionic conductivity, expedite electron transfer, and improve Zn‐ion diffusion. [ABSTRACT FROM AUTHOR]

The carrier mobility of solar cell materials is a critical physical parameter that determines the series resistance. Furthermore, series resistance is an essential factor affecting the conversion efficiency of concentrator solar cells under high sunlight illumination. However, there has been slight discussion regarding the relationship between these factors. In the previous study, it was reported that concentrated illumination decreased carrier mobility; however, the scattering mechanism has not yet been clarified. Moreover, carrier–carrier scattering was discussed; however, it did not cause a mobility reduction. Thus effective mass changes are discussed as a possible cause of the decrease in carrier mobility under concentrated illumination. The cause of the decrease in mobility under concentrated sunlight illumination cannot be fully elucidated; however, it is a change in lattice scattering. Furthermore, the effect of the decrease in mobility due to concentrated illumination on the series resistance and conversion efficiency of Si solar cells using numerical calculations is clarified. The increase in the series resistance caused by the mobility reduction is ≈10% under 30 suns. [ABSTRACT FROM AUTHOR]

Thermoelectric materials enable efficient and clean conversion between heat and electricity, offering significant application prospects in waste heat recovery and solid‐state cooling. Lead selenide (PbSe) is a more abundant and cost‐effective alternative to PbTe with promising potential for mid‐temperature applications. However, things have changed very recently with the discovery of the traditional power generator PbSe being rather competitive as a thermoelectric cooler, opening new avenues for investigating this compound. This review aims to comb how the research achievements and promising performance of PbSe have shifted from medium to near‐room temperatures, by comprehensively discussing various strategies to enhance the thermoelectric efficiency at different temperature ranges. Subsequently, it is reviewed how these advances in materials have triggered deep investigations on constructing high‐efficiency power generation and cooling devices based on PbSe. Finally, a personal summary and outlook are presented on how to fully exploit the high‐ranged thermoelectric performance of PbSe materials and manufacture high‐efficiency power generators and coolers, thus promoting practical applications in the future. [ABSTRACT FROM AUTHOR]

When semiconductor crystals are made into the form of thin sheets, i.e., nanomembranes, their properties and behaviors may be remarkably different from their bulk counterparts. A plethora of fascinating science and important applications arise consequently, some of which are investigated in recent years, and there are still a lot more to be discovered in the future. Nanomembranes (NMs) provide a good platform for strain engineering and offer tremendous research opportunities in photonics and optoelectronics applications. Strain alters energy band line up of a material furthermore influencing its carrier mobility which impacts a wide range of applications. In this article, the strain‐engineered NMs are reviewed using semiconductor materials as a model system for photonics and optoelectronics applications. While many fundamental aspects of NMs are discussed and outlined different methods for strain engineering of NM, the use of semiconductor NMs for photonics and optoelectronics applications is the locus of the present review article. [ABSTRACT FROM AUTHOR]

The new halogen‐free donor polymer PCN6 is constructed using 2‐ethylhexyl‐4,6‐dibromo‐3‐cyano‐thieno[3,4‐b]thiophene as acceptor (A) block, and is compared in detail with the commercially available PTB7‐Th. It is found that PCN6 has a wider film absorption (300–700 nm) and lower highest occupied molecular orbital (HOMO) energy levels (−5.52 eV) than PTB7‐Th (−5.34 eV), suggesting a great advantage of the monocyano‐functionalized modification strategy in terms of molecular absorption and energy level tuning. The performance difference between PCN6:Y6‐ and PTB7‐Th:Y6‐based organic solar cells (OSCs) is compared by a series of studies including light intensity dependence, carrier mobility, AFM, TEM, and GIWAXS. The results show that PCN6:Y6‐based OSCs have stronger crystallinity, better charge transport, higher and more balanced carrier mobility, and less exciton complex loss. Therefore, the power conversion efficiency (PCE) of PCN6:Y6‐based OSCs reaches 11.34%, while the PCE of PTB7‐Th:Y6‐based OSCs is only 9.02%. These results suggest that 2‐ethylhexyl‐4,6‐dibromo‐3‐cyano‐thieno[3,4‐b]thiophene is an excellent A block for the construction of halogen‐free donor polymers with low HOMO energy levels, and also demonstrate that the introduction of cyano in the conjugated backbone of polymers is a good strategy to achieve high‐performance OSCs. [ABSTRACT FROM AUTHOR]

The unbalanced electron‐hole mobility is the major bottleneck for boosting the photovoltaic performance of organic solar cells. In this study, 2D n‐type inorganic semiconductor material tin sulfide (SnS) is prepared and introduced into the PM6:Y6 bulk heterojunction organic solar cells to improve photovoltaic performance. The incorporation of SnS promotes Y6 crystallization, and renders the face‐on orientation of Y6 molecules dominant. The improved active layer morphology suppresses carrier recombination and strengthens the electron transport. The electron mobility increases significantly from 4.71 × 10−4 cm2 V−1 s−1 to 7.61 × 10−4 cm2 V−1 s−1 with the hole/electron mobilities (µh/µe) value reducing from 1.67 to 1.11. With enhanced and balanced carrier mobility, the open‐circuit voltage, short‐circuit current density and fill factor of the SnS‐doped PM6:Y6 organic solar cells are improved simultaneously, and the power conversion efficiency is boosted from 16.66 to 18.50%. Additionally, the SnS doped devices exhibit better thermal and storage stability. The improved photovoltaic performance is further verified in PM6:L8‐BO and D18:Y6 based organic solar cells. This work demonstrates that n‐type SnS dopant is an efficient and universal method to improve photovoltaic performance of non‐fullerene organic solar cells. [ABSTRACT FROM AUTHOR]

Organic electrochemical transistors (OECTs) are of great interest owing to their potential applications in bioelectronics and neuromorphic systems. However, n‐type OECTs suffer from poor stability and facile degradation, mainly due to the oxygen reduction reactions in organic mixed ionic‐electronic conductors during device operation. In this study, a small‐molecule passivation strategy is introduced to greatly improve the stability of poly(benzobisimidazobenzophenanthroline) (BBL)‐based n‐type OECTs. 6,6‐Phenyl‐C61‐butyric acid methyl ester (PCBM) is spin‐coated onto the BBL layer to form a smooth and hydrophobic passivation layer, which effectively inhibits the oxygen reduction reactions while enabling ion permeation in aqueous electrolytes. Consequently, the OECTs employing the PCBM/BBL bilayers with an optimized PCBM thickness exhibit significantly improved operational stability at various electrolyte conditions (0.1 m NaCl or NaOH) and over a wide gate‐voltage sweep range (from −0.7 to 0.7 V). Owing to the high electron mobility of PCBM, the carrier mobility and switching speed of the PCBM/BBL OECTs are also improved compared with those of the pristine BBL OECTs. This study demonstrates the beneficial effects of simple surface passivation in organic mixed ionic‐electronic conductors and provides valuable insights for the design of high‐performance and stable OECTs for more specialized and advanced applications. [ABSTRACT FROM AUTHOR]

A key factor for improving the performance of the hydrogen photocatalytic reaction is the logical, functional, and effective design of the photogenerated charge transfer through the solid-solid interface in a heterojunction. This point is particularly crucial in cases such as the one of TiO 2 , where a relatively rapid recombination occurs. In this work, a Zn x Ti y O z /TiO 2 heterojunction using the sol-gel nucleation is presented. This method gives rise to a strong and efficient interaction between Zn x Ti y O z and TiO 2 , increasing the photocatalytic activity. Moreover, the addition of Co, Cu or Pd species to the heterojunction surface increases the hydrogen production, due to the strong interaction between them as shown by HRTEM and XPS analyses. Furthermore, the (photo)electrochemical characterization shows that the resistance to charge transfer decreases with co-catalysts, observing the following trend: Pd < Cu < Co. This outcome is related to the mobility and separation of charge carriers and the role played by co-catalysts in hydrogen production. [Display omitted] • Co, Cu and Pd were deposited onto Zn x Ti y O z /TiO 2 via incipient wetness impregnation. • Characterization of co-catalyst-Zn x Ti y O z /TiO 2 evidenced the formation of heterojunctions. • XPS evidenced the enhanced contribution of Co, Cu and Pd species onto Zn x Ti y O z /TiO 2. • Hydrogen production increased up to 2.7 times by using Pd species co-catalyst. • Co, Cu, and Pd on the heterojunction enhanced charge carrier mobility and separation. [ABSTRACT FROM AUTHOR]

Thin films of zinc stannate, both pure and doped with antimony, were synthesized via the RF sputtering method. X-ray diffraction patterns showed SnO 2 and Zn 2 SnO 4 phases. Atomic force microscopy analysis demonstrated that doping resulted in a reduction of the films roughness from 2.48 to 1.07 nm, attributed to an increase in grain density. Photoluminescence spectra exhibited a broad visible emission band with a peak centered around 557 nm. Transparency in the visible region was high for the films, reaching 80%. The electrical studies revealed that the resistivity decreased with doping upto 8.54 × 10 - 2 Ω cm due to the increase in charge carriers concentration and mobility. [ABSTRACT FROM AUTHOR]

Band gap engineering based on doped two‐dimensional (2D) transition metal dichalcogenides (TMDs) has shown great potential in the design and development of new nano photoelectronic devices and their application in photoelectrocatalysis. However, there are two key issues that are difficult to take into account, namely the impurity levels induced by dopant atoms appear in the forbidden band of the doping system, which can become the recombination center of photogenerated carriers, thereby reducing the photocatalytic efficiency. Compared with the carrier mobility of the corresponding doped systems, that of intrinsic 2D TMDs is too low. Understanding the doping mechanism of heteroatoms in these systems and designing corresponding crystal structures rationally is important for solving these problems. In this study, the crystal structures of co‐doped monolayer WS2 with Nb and Re atoms were designed using density functional theory, and doping systems with graphene (high carrier mobility) were assembled into a heterostructure using the concept of heterorecombination. The N‐P type co‐doping of Nb and Re atoms retained the continuous band characteristics of the original monolayer WS2 while also providing the high carrier mobility of graphene, yielding an excellent multipurpose material for manufacturing high‐speed Schottky devices and efficient water‐splitting H evolution catalysts. [ABSTRACT FROM AUTHOR]

Metal halide perovskites have recently garnered significant attention as a fundamental emitter due to their high carrier mobility, strong light absorption, high monochromaticity, and tunable emission bandgap. However, the brightness, efficiency, and stability issues have limited their potential applications in blue region. To break through these limitations, researchers have investigated different dimensions of perovskites to seek an excellent emitter. To date, the quantum confinement and coordination octahedron monomer arrangement perovskites still lack of systematic cognition. In this review, the molecular and morphological dimensions of blue perovskite emitters are summarized. The differences and relationships between these dimensions in terms of their fabrication and properties are also explored. Furthermore, recent advances in blue light enhancement strategies to address the challenges in various morphological and molecular structures are highlighted. Finally, the main challenges and future directions are discussed for the development of perovskite blue LEDs. [ABSTRACT FROM AUTHOR]

Providing self-powered energy for wearable electronic devices is currently an important research direction in the field of thermoelectric (TE) thin films. In this study, a simple dual-source magnetron sputtering method was used to prepare Ag2Te thin films, which exhibit good TE properties at room temperature, and the growth temperature and subsequent annealing process were optimized to obtain high-quality films. The experimental results show that films grown at a substrate temperature of 280 °C exhibit a high power factor (PF) of ~3.95 μW/cm·K2 at room temperature, which is further improved to 4.79 μW/cm·K2 after optimal annealing treatment, and a highest PF of ~7.85 μW/cm·K2 was observed at 200 °C. Appropriate annealing temperature effectively increases the carrier mobility of the Ag2Te films and adjusts the Ag/Te ratio to make the composition closer to the stoichiometric ratio, thus promoting the enhancement of electrical transport properties. A TE device with five legs was assembled using as-fabricated Ag2Te thin films. With a temperature difference of 40 K, the device was able to generate an output voltage of approximately 14.43 mV and a corresponding power of about 50.52 nW. This work not only prepared a high-performance Ag2Te film but also demonstrated its application prospects in the field of self-powered electronic devices. [ABSTRACT FROM AUTHOR]