Granted by the suitable characteristics of its electronic band structure, high electron mobility, and remarkable durability, P(NDI2OD-T2) stands out among conjugated polymers and is regarded as a prominent candidate for electron accepting materials in the third generation of photoelectrochemical and photovoltaic devices. However, a comprehensive understanding of exciton-polaron interactions, which provides the key to optimizing the efficiency of these devices, is lacking. In this study, we fabricated P(NDI2OD-T2) into a film working electrode of an electrochemical cell and changed its surrounding electrochemical environments by exerting different electric biases. Transient absorption (TA) spectroscopy was employed synchronously to interrogate the corresponding exciton dynamics. Careful inspection of the TA spectra of P(NDI2OD-T2) under different electrochemical conditions gives detailed insights into the interactions between excitons and polarons. Our results highlight that polarons have a significant influence on exciton behavior. Merely applying cathodic biases without efficiently doping the polymer yields excited-state dynamics similar to that in the neutral state. However, in the presence of polarons, the lifetime of excitons is significantly reduced by ∼5 times. Through analyzing the TA spectra and kinetics of P(NDI2OD-T2) at -1.0 and -1.2V (vs Ag/Ag+ reference electrode), an efficient exciton-polaron quenching effect was identified. Furthermore, we report the absorption features of the excited states of polaron, i.e., charged excitons (trions) in P(NDI2OD-T2). We propose that bipolarons and such charged excitons may have similar electronic structures as they manifest resemblance in their absorption features. Our strategy of integrating ultrafast spectroscopy and electrochemistry to investigate the exciton-polaron interactions in polymers provides an effective methodology in research fields of photoelectrochemistry and photovoltaics, more broadly applicable beyond soft materials.

Through first-principles calculations, the structural evolution, carrier mobility, and superconductivity of anti-perovskite Ca3BiX (X = H, N, P) have been investigated in the 0-100 GPa range. Results indicate that Pm3̄m, R3̄m, P63/mmc, P4/mmm, Cmcm, Pnma, and C2/m are stable phases in the corresponding pressure regions. Moreover, phase transitions occur in Ca3BiH from Pnma to Pm3̄m and R3̄m phases at 8 GPa, in Ca3BiN from Pm3̄m and P4/mmm to P63/mmc phases at 73 GPa, and in Ca3BiP through three transitions: Pnma → C2/m at 5 GPa, C2/m → Cmcm at 10 GPa, and Cmcm → C2/m at 22 GPa. More importantly, the electron mobility of the Pnma phase of Ca3BiP is anisotropic and reaches 7.1 × 104 cm2 V-1 s-1 in the x direction, exceeding the recently reported result of the anti-perovskite Rb4I2O (5.3 × 104 cm2 V-1 s-1) in the z direction. Meanwhile, electron-phonon coupling calculations show that the superconducting transition temperature (Tc) of the Pm3̄m phase of Ca3BiH reaches 7.2 K at 50 GPa, which is higher than that of the comparable Ca-based anti-perovskite Ca3PN (4 K). These results not only enrich research on Ca-based anti-perovskites under high pressure, but also provide theoretical support for further studies of the mobility and Tc of Ca-based anti-perovskites.

Entropy-driven dual-phase engineering in sulfides via synergizing metallic conduction and disorder-interface polarization for microwave absorption.

Improved RF linearity AlGaN/AlN/GaN high electron mobility transistor on low loss Mn-doped semi-insulating GaN substrate

Two-dimensional semiconductors offer a pathway toward ultrascaled electronics, yet achieving strong electrostatic gate control without sacrificing low-resistance contacts remains a fundamental challenge. Here, we report a selective defect-engineering strategy that addresses this gate-contact trade-off in Bi2O2Se transistors. Low-temperature nitrogen incorporation passivates selenium vacancies through robust N-Bi bonding, suppressing intrinsic self-doping while preserving the intrinsic band dispersion without introducing midgap states. Density functional theory and scanning tunnelling spectroscopy reveal that nitrogen provides acceptor-like compensation by neutralizing vacancy-induced donor states, rather than through conventional substitutional doping. As a result, the Fermi level shifts toward midgap, enabling precise carrier-density modulation while maintaining band-like transport. By spatially confining nitrogen incorporation to the channel region, Bi2O2Se field-effect transistors are converted from depletion to enhancement mode, achieving high electron mobility and on/off ratios up to 109 while preserving ohmic, contact-transparent injection. This selective defect-engineering approach decouples channel electrostatics from contact properties and provides a potentially scalable, thermally benign route toward gate-controllable, contact-transparent two-dimensional transistors compatible with integrated logic architectures.

We report the synthesis and characterization of homoleptic Co(II), Ni(II), Cu(II), and Zn(II) complexes of a phenol-substituted aza-dipyrromethene ligand. The complexes adopt distorted tetrahedral geometries, display ligand-centered redox activity, and exhibit panchromatic absorption. Chemical and electrochemical oxidation of the ML2 complexes generate quinone/bis(diradicaloid) species that exhibit strong near-infrared absorption and antiferromagnetically coupled ligand-centered spins in the Zn(II) complex. Charge-transport measurements reveal modest electron mobilities and unusually high hole mobilities (≈10-3 cm2 V-1 s-1) for the quinone/bis(diradicaloid) complexes, making them potential hole transport materials. DFT and TD-DFT calculations confirm ligand-dominated frontier orbitals with metal-dependent electronic modulation. These results highlight aza-dipyrromethene metal complexes as promising platforms for redox-active and charge-transport materials.

Organic semiconductors require both high carrier mobility and structural diversity, but direct first-principles evaluation is costly and brute-force exploration of chemical space is infeasible. We propose a data-driven framework that combines a hierarchical variational autoencoder (HVAE), Gaussian mixture regression (GMR), and Bayesian optimization to design small molecules exhibiting low reorganization energy and high carrier mobility. An HVAE was trained to learn a latent representation of organic semiconductor-like molecules, and GMR linked latent variables to hole and electron reorganization energies. By (i) adding random noise around low-reorganization energy molecules in the latent space and (ii) sampling from a Gaussian mixture model fitted to their latent distribution, we generated structurally reasonable candidates under constraints on ring number and molecular size, including a molecule with a new minimum hole reorganization energy obtained via sulfur-to-nitrogen substitution. Subsequent Bayesian optimization using reorganization energy and a small set of structural descriptors identified molecules with high mobilities and confirmed reorganization energy as a key descriptor for both hole and electron mobility.

Dimeric acceptors have recently emerged as promising giant molecule acceptors (GMAs) for organic solar cells (OSCs), but most systems link two identical monomeric units. Hybrid GMAs combining different acceptor units remain unexplored. Herein, we develop a core-to-wing type hybrid strategy coupling BT- and BZ-core acceptor units through flexible ester-linked alkyl chains, affording three GMAs (BTZ-2-2, BTZ-2-6, and BTZ-2-10). This design enables complementary absorption by combining the spectral features of BT- and BZ-based monomers while preserving favorable crystallization behavior. Among them, BTZ-2-6 exhibits the broadest, most red-shifted absorption, enhanced π-π stacking, and the highest electron mobility due to the optimal length of its ester-linked alkyl chain. The PM6:BTZ-2-6 binary device delivers 18.53% efficiency and retains nearly 90% of its initial efficiency after 720h of illumination. Furthermore, the efficiency can be increased to 19.41% by replacing PM6 with D18 as the donor polymer, and further boosted to 20.25% by incorporating BTZ-2-6 as a third component into PM6:L8-BO binary devices. These results demonstrate that core-to-wing hybrid GMAs with ester-linked alkyl chains of different lengths provide an effective strategy for constructing high-performance GMAs, offering new opportunities for efficient and stable OSCs.

Raising the LUMO level of fullerene derivatives is essential for minimizing voltage losses in tin halide perovskite photovoltaics. Multi-adducts effectively raise the LUMO level but produce inseparable isomeric mixtures and weaken electron mobility. Mono-addition with electron-donating groups avoids these issues but typically provides only modest LUMO elevation. Herein, we show that simply replacing triphenylamine with indoline elevates the LUMO level by 90 meV, approaching the enhancement achieved by bis-PCBM. This single-substitution strategy simultaneously minimizes voltage loss and preserves electron mobility, circumventing the classic trade-off in fullerene electron-transport materials.

Optimizing the quality and biosafety of fermented corn noodles: The role of Lactiplantibacillus plantarum in microstructural remodeling and flavor biogenesis.

The recently synthesized monolayer MoSi2N4 (Y.-L. Hong, Z. Liu, L. Wang, T. Zhou, W. Ma, C. Xu, S. Feng, L. Chen, M.-L. Chen and D.-M. Sun, Chemical vapor deposition of layered two-dimensional MoSi2N4 materials, Science, 2020, 369(6504), 670-674.) boasts extraordinary environmental stability and superior comprehensive performance, offering exciting opportunities for the exploration of two-dimensional MX2Z4 materials. However, the low carrier mobility of α-MoSi2N4 significantly limits its practical applications in field-effect transistor (FET) devices. In this study, first-principles calculations were utilized to systematically investigate the structural stability, photoelectronic properties, tensile mechanical behavior, and carrier mobility of a novel family of β-SnA2N4 (A = Si, Ge) monolayers. Our findings reveal that these β-SnA2N4 monolayers demonstrate remarkable dynamic and thermal stability. Specifically, calculations based on the HSE06 functional reveal that the SnSi2N4 and SnGe2N4 monolayers are semiconductors with band gaps of 3.36 eV and 2.13 eV, respectively. Additionally, the SnA2N4 monolayers exhibit distinct mechanical anisotropy, characterized by high ideal tensile strengths and critical tensile strains exceeding 27%, indicating outstanding ductility. Importantly, the SnA2N4 monolayers display exceptional anisotropic in-plane charge transport, achieving electron mobility levels of up to 103 cm2 V-1 s-1, surpassing those of the α-phase MA2N4 (M = Mo, W; A = Si, Ge) monolayers. These novel ternary monolayer structures are expected to enrich the 2D MA2Z4 material family and emerge as promising candidates for FET applications.

Theoretical study on manipulating core structure and energy level of non-fused ring electron acceptors in organic solar cells.

This first-principles study systematically investigates the structural, electronic, and optoelectronic properties of M2XT2/SiC (M = Sc, Y; X = C; T = F, Cl, Br) van der Waals heterojunctions. The four examined systems (Sc2CBr2/SiC, Sc2CCl2/SiC, SiC/Y2CF2, and SiC/Y2CCl2) retain their monolayer band characteristics while forming stable heterojunctions with indirect bandgaps. The first three configurations clearly show that the VBM and CBM are confined in SiC and M2XT2, respectively, indicating a type-II band alignment. However, for SiC/Y2CF2, both the VBM and CBM are confined in Y2CF2, indicating a type-I band alignment. Notably, SiC/Y2CCl2 demonstrates exceptional electron mobility (6.99 × 103 cm2 V-1 s-1). Charge density difference analysis reveals electron transfer from SiC to MXene layers, facilitated by a built-in electric field that suppresses carrier recombination. All heterojunctions exhibit enhanced light absorption and reduced bandgaps compared to SiC, with SiC/Y2CF2 showing an optimal photoresponse at 3.2 eV photon energy and the highest extinction ratio. These findings highlight the potential of MXene/SiC heterojunctions for tailored optoelectronic applications.

Hematite (α-Fe2O3) is a promising photoanode for solar water splitting, while its performance is fundamentally limited by low bulk electron mobility and severe surface charge recombination. Doping has been demonstrated to be an effective strategy to address these issues at the atomic level. Herein, we present a rational dual-site doping design that synergistically enhances bulk charge transport and suppresses surface recombination. In situ ytterbium (Yb3+) doping in the bulk modulates the local chemical environment of Fe3+ and introduces lattice distortion, which is favorable for improving bulk charge transport behavior. Meanwhile, ex situ zirconium (Zr4+) surface modification effectively suppresses interfacial charge recombination through surface state regulation. In addition, the hybrid microwave annealing (HMA) process promotes the formation of porous nanostructures. Benefiting from these synergistic effects, the optimized Yb,Zr:Fe2O3 photoanode achieves a remarkable photocurrent density of 3.51 mA cm-2 at 1.23 VRHE under AM 1.5 G illumination (100 mW cm-2), along with an enhanced operational stability. This work demonstrates the efficacy of dual-functional doping in engineering high-performance hematite photoanodes and provides a strategic framework for rational design of advanced metal oxide photoelectrodes.

Indium-arsenide (InAs) nanowire field-effect transistors (NWFETs) combine high electron mobility with extreme surface sensitivity, making them promising platforms for biochemical agent detection at room temperature. Yet understanding the relative roles of electrostatic screening, impurity scattering, and molecular charge transfer in governing their response remains incomplete. Here, we couple time-resolved measurements of multi- nanowire InAs FETs exposed to dimethyl methylphosphonate (DMMP) vapor (50-200 ppb) with a self-consistent charge-neutrality solver that incorporates Kane-model sub-band structure and Brooks-Herring ionized-impurity scattering. We uncover a gate-tunable "electrostatic sweet spot'' in which depletion of the one-dimensional carrier gas both perturbs the overall charge landscape and lengthens the Debye screening length to the nanowire diameter, yielding a six-fold gain in sensitivity and a limit of detection of 50 ppb. In this regime, quantitative fitting shows that ≈75 electrons are withdrawn from the channel per ppm of DMMP where an 80% reduction of the baseline carrier pool that drives the nonlinear response exists. The model accurately reproduces the measured gain, resolves the separate contributions of charge transfer and scattering, and maps how geometry (radius, oxide thickness), bias, and temperature steer sensor performance. Because the framework depends only on material-specific band and trap parameters, it can be ported directly to other semiconductor/molecule combinations-e.g., Si or metal-oxide nanowires sensing volatile organic compounds-providing a predictive pathway for rational design of low-power, high-dynamic-range chemical sensors for environmental monitoring and industrial safety applications.

The inherent susceptibility of n-type organic semiconductors to molecular dioxygen (O2) results in electron trapping or in unintended p-doping, which in turn diminishes their electron mobility. This concept is challenged in the present study by exploring O2 interactions with organic charge-transfer complexes (CTCs), where electron donor-acceptor interactions generate partially delocalized electronic states. Using a CTC comprising a phenazine electron donor and a 7,7,8,8-tetracyanoquinodimethane (TCNQ) electron acceptor, we demonstrate that its exposure to O2 does not lead to electron extraction but instead enhances the charge-transfer activity. The increased electron density at the TCNQ acceptor upon CTC exposure to O2 is attributed to electron trap-states passivation by O2, without evidence of chemisorption. This passivation mitigates recombination losses, resulting in a threefold photoluminescence quantum yield increase, enhanced electrical conductivity, and improved charge-transfer state efficiency. Similar O2-mediated conductivity enhancements are observed across additional donor-acceptor pairs, proving the broader applicability of this effect, and paving the way for designing O2-enhanced advanced organic electronic materials.

Two-dimensional (2D) heterostructures provide a versatile platform for solar energy conversion owing to their highly tunable electronic structures and flexible van der Waals integration. However, the efficient discovery of high-performance photocatalytic and photovoltaic heterostructures remains challenging due to the vast combinatorial space, the need to sustain both strong oxidation and reduction reactions for photocatalysis, and inherent trade-offs among efficiency, charge transport, and stability in photovoltaics. Here, we develop a physically guided and data-driven strategy for the systematic discovery of functional 2D heterostructures for catalysis and photovoltaics. By employing machine learning-assisted predictions to complete missing hybrid functional-level electronic structure data for monolayers in the Computational 2D Materials Database, we enable exploration of a heterostructure landscape comprising over 510 000 candidates. For photocatalytic water splitting, direct high-performance Z-scheme heterostructures are identified using physically motivated descriptors based on band offsets and material electronegativity differences, enabling the realization of strong oxidation and reduction capability together with favourable light absorption. For photovoltaic applications, we indicate that evaluating band alignment and theoretical power conversion efficiency alone is insufficient to assess realistic device potential. Incorporating carrier mobility as a key descriptor is essential for capturing charge transport limitations that critically influence device performance. Remarkably, the HfBr2/HfICl heterostructure exhibits a power conversion efficiency above 21%, along with ultrahigh and well-balanced electron and hole mobilities of 3083 and 7551 cm2 V-1 s-1, respectively. The strategy established here offers a physically transparent route for discovering next-generation optoelectronic materials across expansive chemical spaces.

The development of chiral organic semiconductors with efficient circularly polarized light (CPL) detection capability is crucial for advanced optoelectronic applications, such as secure communication and optical information processing. However, translating their promising molecular-level chirality into solid-state devices remains a challenge. The core issue lies in the difficulty of controlling the quality of the active film during film formation, including ordered molecular packing and suppressed surface defects, which governs both charge transport and chiral expression. Herein, we demonstrate high-quality thin films of a novel n-type chiral π-conjugated polymer, (S)-P(NDI2MH-T), fabricated via a kinetically controlled dip-coating method. Systematic investigation of the dip-coating parameters, particularly tailoring the surface wettability, identifies that the substrate with a contact angle of ∼36° and a temperature of 25 °C at a polymer concentration of 5 mg mL-1 yields continuous, pinhole-free films with enhanced molecular ordering. Based on these films, organic n-type phototransistors demonstrate a high electron mobility of 0.82 cm2 V-1 s-1 and a high photoresponsivity of 38 A W-1. Furthermore, the devices show pronounced chiral selectivity towards CPL, with a photocurrent dissymmetry factor (gph) of up to 0.28. Leveraging this selectivity, we successfully demonstrate the application of the device in binary logic information encoding and decoding, mimicking Morse code communication. This work provides a viable pathway from material processing to device integration for constructing sensitive and integrable chiral optoelectronic systems.

Two-dimensional (2D) layered GalnS3 materials have attracted huge attention due to their excellent anisotropic photoelectric properties for photovoltaic devices. However, the monolayer α-GaInS3 possesses an indirect band gap, which significantly limits its practical applications. Therefore, we constructed non-centrosymmetric GalnS3-like monolayers, namely, ABM3 (A = Ga, In, Al; B = Ga, In, Al; M = S, Se, Te), and investigated their electronic and excitonic properties using high-precision G0W0-BSE methods. Our results indicated that β-GaInS3, GaAlSe3, and AlInSe3 monolayers possess direct band gaps with desirable structural stability. Moreover, the built-in electric potential differences of these non-centrosymmetric monolayers can promote the separation of photon-generated carriers. Importantly, the three ABM3 monolayers exhibit larger exciton binding energy with a BSE optical band gap in the visible light range, and their exciton lifetime is up to 7.05 ps for β-GaInS3 at 0 K. In addition, these three structures exhibit highly anisotropic electron mobilities (up to ∼103 cm2 V-1 s-1) due to their larger lattice anisotropy.

Monolithic 3D integration of oxide thin-film transistors provides an approach to continue Moore's Law. Crystalline indium oxide (In2O3) is particularly attractive owing to its high electron mobility and low contact resistance. However, its practical deployment is hindered by the difficulty of fabricating crystalline In2O3 under BEOL-compatible conditions and by the intrinsic instability of surface oxygen. In this work, we demonstrate an atomic-layer-deposition-enabled stabilization strategy that simultaneously achieves high mobility, strong electrostatic control, and exceptional stability in crystalline In2O3 transistors. The afforded devices exhibit a high electron mobility of 92.8 cm2/V·s, a positive threshold voltage of 0.67 V, a steep subthreshold swing of 64.5 mV/dec, and fairly small threshold voltage shifts of -5.6 and 18.6 mV under negative- and positive-bias stress, respectively. Furthermore, the devices show good resistance to forming gas annealing, with small threshold voltage shifts and no degradation in subthreshold swing or on-current. This work not only provides valuable insight into the origin of instability for crystalline oxide semiconductors, but also demonstrates a practical fabrication approach at CMOS BEOL-compatible temperatures to achieve both high performance and high stability for oxide transistors, thereby highlighting the high promise of indium oxide transistors for advanced M3D integration.