Self-assembled monolayers (SAMs) are widely used as hole-transport layers (HTLs) in organic solar cells (OSCs), yet conventional single-component SAMs often form quasi-monolayers with incomplete coverage and interfacial defects that become increasingly detrimental upon device scaling. Here, we develop a co-assembled multilayered SAM (coSAMu) strategy that combines two SAM molecules, 2PACz and 2Cl-4PACz, with distinct dipoles and steric configurations through blend casting and sequential casting. Photoelectron spectroscopy, X-ray analysis, and molecular simulations support a layered structure in which a chemisorbed, 2PACz-rich bottom layer primarily sets the indium tin oxide (ITO) work function, while a 2Cl-4PACz-rich upper layer fills interfacial voids, improves molecular packing, and passivates defects. Consistent with this picture, coSAMu promotes a more favorable vertical composition near the ITO surface and suppresses trap-assisted recombination, enabling more efficient charge extraction and collection. Consequently, a representative D18:L8-BO OSC incorporating the sequential-cast coSAMu HTL achieves a power conversion efficiency of 20.1% (0.042 cm2), outperforming pristine 2PACz. Importantly, when scaled to a 17.14 cm2 mini-module (six serially connected subcells), coSAMu delivers 17.0% efficiency versus 12.2% for the 2PACz control. This work demonstrates controlled multilayer co-assembly as an effective strategy for scalable OSC interface engineering that is broadly applicable to multiple donor-acceptor systems.

Covalent organic frameworks (COFs) are promising lithium-ion battery electrodes because of their tunable structures and porous architectures. However, research on COF-based lithium-ion battery (LIB) electrodes has primarily focused on rigid frameworks, with limited attention to flexible COFs. In this work, two types of COFs with distinctly different mechanical properties-rigid (Rig) and flexible (Flx)-were synthesized via a skeleton engineering strategy. To overcome low electronic conductivity, the COFs were grown in situ on carbon nanotubes (CNT) to form conductive composites. Both COFs exhibited high crystallinity, large surface areas, and well-defined pore structures. Comparative electrochemical studies revealed that Flx-4C delivered improved long-term capacity retention and rate performance, reaching a maximum capacity of 582 mAh & centerdot;g- 1 at 2 C, surpassing the theoretical capacity of commercial graphite. Cross-sectional SEM and confined powder compaction tests show that the flexible framework undergoes smaller thickness growth and higher mechanical energy dissipation, indicating improved buffering of cycling-induced deformation. Ex situ XPS and DFT calculations suggest that quinone/hydroxyl, imine, triazine, and ether-related sites participate in lithium storage, consistent with a 24-electron redox process per repeating unit of Flx. This work offers critical insights into the structure-performance relationship of rigid vs flexible COFs, guiding the design of advanced organic electrode materials.

The Rashba effect is a manifestation of spin-orbit coupling in systems with structural inversion asymmetry, resulting in a spin-dependent splitting of energy bands in low-dimensional systems. This gives rise to diverse spin-dependent phenomena in semiconductor heterostructures, offering significant potential for spintronic applications. However, a comprehensive theoretical characterization remains incomplete, since most existing approaches are restricted to relatively small structures. In this work, we combine the well-established eight-band Kane model and envelope-function formalism with a recently developed Green's function approach. The framework allows to obtain analytical expressions for the spin-dependent coherent transport in semiconductor heterostructures with an arbitrary number N of cells exhibiting the Rashba effect. In addition, we propose guidelines for enhancing spin polarization and spin-miniband separation in extended semiconductor heterostructures by tuning structural inversion asymmetry. Furthermore, we find that as a geometric parameter is varied, the spin-splitting dynamics present the quantum avoided-crossing behavior. We finally show that, for suitably designed heterostructures, the polarization bands can exhibit step-like (rectangular-wave) profiles. Although our examples focus on GaAs/In-based systems, the results are expected to hold for other semiconductor materials as well.

Despite the rapid advancements in the performance of organic solar cells (OSCs), improving their operational lifetime remains a significant challenge. The photodegradation of donor polymer PM6, small molecule non-fullerene acceptor (NFA) Y6, and their blend was investigated under ambient conditions. To photodegrade the spin-coated thin films, samples were exposed to AM 1.5 illumination, as well as UV-filtered and long-wavelength-filtered light. The evolution of their properties upon increasing the exposure time up to 45 h was monitored using UV-vis absorption, Fourier transform infrared (FTIR), and photoemission spectroscopy. The results demonstrate that neat PM6 films exhibit faster absorbance loss than the neat Y6 films. This is accompanied by the formation of new carbonyl groups on PM6, while only minor indications of photooxidation were observed in degraded Y6 films. The valence band spectra of Y6 remain unchanged upon photodegradation. Interestingly, the photobleaching rate of Y6 in PM6:Y6 blend films was found to be higher than that of neat Y6 films. XPS spectra of C 1s and S 2p confirm that photooxidation products formed in PM6 and PM6:Y6 films, evidenced by new oxidized carbonyl C 1s and oxidized sulfur S 2p peaks. Under AM 1.5 illumination, several photooxidation pathways can be active, involving the formation of both superoxide radicals and singlet oxygen species and their subsequent oxidation reactions with conjugated molecules. Using filtered light conditions, these different degradation pathways could be separated. Upon exposure to long-wavelength-filtered light, which is predominantly absorbed by the Y6 acceptor, the generation of superoxide radicals is significantly suppressed, resulting in enhanced photostability of the blend compared to illumination with unfiltered light. The remaining photodegradation of the blend components under these illumination conditions can therefore be ascribed to energy transfer from the photosensitizing acceptor, feeding into the singlet oxygen formation. These insights could inspire the design of new donor and acceptor materials with improved photostability by tuning the positions of their singlet and triplet states to minimize the formation of oxygen-mediated reactive species.

In this study, we employ ab initio density functional theory (DFT) calculations to elucidate the microscopic origin of the Jahn-Teller distortion suppression and magnetic moment quenching in LiNiO2 (LNO) during delithiation. Our results reveal that these effects arise not from changes in the Ni oxidation state but from an electronic charge redistribution between the eg and t2g orbitals derived from Ni-3d states. This internal electronic rearrangement, driven by strong hybridization between Ni-3d and O-2p orbitals, accounts for the inactivation of the Jahn-Teller distortion and the quenching of the magnetic moment at the NiO6 octahedra. The same mechanism also explains the shifts observed in the Ni and O K-edge X-ray absorption near-edge structure (XANES) spectra during delithiation. Our findings provide a new microscopic interpretation of the LNO redox process, highlighting the role of electron redistribution within the Ni-3d manifold as the true origin of its structural and magnetic transformations.

Zinc-ion batteries (ZIBs) employing aqueous electrolytes have emerged as one of the most promising alternatives to lithium-ion batteries (LIBs). Nonetheless, the development of ZIBs is hindered by the scarcity of cathode materials with suitable electrochemical properties. In this work, we investigate the unique properties of zinc vanadate oxide (ZnV2O4, ZVO) and zinc vanadate sulfide (ZnV2S4, ZVS) compounds as cathode materials, focusing on their crystal structures, electrochemical performance, spectroscopic features and potential applications in ZIBs. Additionally, we investigate a new cathode material, zinc vanadate selenide (ZnV2Se4, ZVSe), constructed by replacing sulfur with selenium in the ZVS cubic structure. Our findings reveal that these compounds exhibit distinct electronic and electrochemical properties, although they have similar magnetic properties due to the fact that vanadium has the same oxidation state in all three compounds. On average, ZVS stands out as the most promising candidate for ZIBs cathodes, followed by ZVO. ZVSe, shows lower electrochemical performance and also has the obvious drawback of being more costly than the sulfur- and oxygen-based compounds. Our theoretical results align closely with available experimental data, both for electrochemical properties as well as x-ray and photoelectron spectroscopy, where a comparison can be made. 

The increasing demand for sustainable energy storage has driven significant interest in zinc-ion batteries (ZIBs) as a cost-effective and environmentally friendly alternative to lithium-ion batteries (LIBs). In this study, we present a computationally driven approach to accelerate the discovery and design of cathode materials for rechargeable ZIBs, combining data filtering techniques with ab initio simulations. By screening 153 902 inorganic compounds from the Materials Project database, we identify eight promising candidates for cathode materials, among which ZnCrO4, ZnMnO3, and ZnMoO4 exhibit the most favorable electrochemical properties for large-scale applications, and where ZnCrO4 has not been discussed before, neither theoretically nor experimentally. These materials demonstrate minimal volumetric changes (less than 6%) during charge–discharge cycles, high theoretical specific capacities, elevated energy densities, high voltages, and reduced ionic diffusion barriers, all of which are critical for optimizing ZIB performance. Our findings highlight the potential of high-throughput computational screening to accelerate the development of next-generation energy storage materials, providing valuable insights for future experimental validation.

Acidochromic materials possess significant potential for the development of molecular switches, acid sensors, smart displays, and erasable/reprintable media. The semiconductive nature of conjugated polymers exhibiting such a behavior makes them ideal for use in electronic devices. In this study, we present a comparative investigation of three indacenodithiophene-based conductive polymers, containing azo, imine, and vinyl bonds (namely, PIDT-BAB, PIDT-BIB, and PIDT-BVB, respectively). We examined the alterations in the spectral properties of these polymers upon exposure to trifluoroacetic acid (TFA). The acidochromic response of PIDT-BAB and PIDT-BIB is indicated by DFT calculations to occur via protonation at the nitrogen atom. PIDT-BIB demonstrated heightened sensitivity to TFA. Conversely, PIDT-BVB did not display acidochromic properties in the film but was responsive to TFA in solution through acid doping. Repeated exposure of polymer films was used to examine the robustness of the polymers over 50 cycles. DFT calculations showed an increase in the planarity of PIDT-BAB and PIDT-BIB backbones as a result of protonation. This effect was particularly strong in PIDT-BAB, resulting in an unusually large bathochromic shift of 510 nm. The corresponding pink-to-transparent transition is particularly interesting for applications in sensors. Our findings provide valuable guidelines for the design of conjugated polymers tailored for acidochromic devices.

Aqueous-processable materials are desired to produce and commercialize eco-friendly organic solar cells. Despite the achievement of developing aqueous soluble electron donor and acceptor polymers by incorporating polar side chains (SCs), the efficiency of the greenest devices is lower than that of state-of-the-art technology processed on halogenated solvents. To investigate the impact of different substituents on structural and optical properties in solution, we considered the backbone of the PTQ10 polymer with alkyl and alkoxy SCs. We simulated oligomer chains at low and high concentration conditions via classical molecular dynamics simulations, considering both a water/ethanol mixture and chloroform as solvents. Combining an unsupervised machine learning technique and density functional theory calculations, we validated the system size for quantum calculations and investigated the impact of SCs on the excited states. Then, following the sequential QM/MM approach, we determined the absorption spectra of each polymer. From the simulations at high concentrations, we observed the stacking of different oligomers, suggesting that polymer chains already showed aggregation in solution. This is consistent with our experimental findings, as we measured a red shift of the PTQ(8bO2) spectrum when changing from a chloroform mixture to an aqueous mixture. Finally, we investigated idealized dimer interface models, whose presence of electron-donating and electron-accepting groups results in mixed signatures in the absorption spectra, widening our understanding of polymer aggregation.

Carbazole-based self-assembled monolayer (SAM) materials as hole transport layers (HTL) have led organic solar cells (OSCs) to state-of-the-art photovoltaic performance. Nonetheless, the impact of the alkyl spacer length of SAMs remains inadequately understood. To improve the knowledge, four dichloride-substituted carbazole-based SAMs (from 2Cl-2PACz to 2Cl-5PACz) with spacer lengths of 2-5 carbon atoms is developed. Single crystal analyses reveal that SAMs with shorter spacers exhibit stronger intermolecular interactions and denser packing. The molecular conformation of SAMs significantly impacts their molecular footprint and coverage on ITO. These factors result in the highest coverage of 2Cl-2PACz and the lowest coverage for 2Cl-3PACz on ITO. OSCs based on PM6:L8-BO with 2Cl-2PACz as HTL achieved high efficiencies of 18.95% and 18.62% with and without methanol rinsing of the ITO/SAMs anodes, corresponding to monolayer and multilayer structures, respectively. In contrast, OSCs utilizing the other SAMs showed decreased efficiencies as spacer length increased. The superior performance of 2Cl-2PACz can be attributed to its shorter spacer, which reduces series resistance, hole tunneling distance, and barrier. This work provides valuable insights into the design of SAMs for high-performance OSCs.