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Thermal atomic layer deposition (ALD) is used for the first time to deposit iron‐nickel oxides onto carbon nanotubes in a ternary process to produce a wide range of mixed oxide thin films. When using ferrocene (FeCp2) and nickelocene (NiCp2) with ozone (O3) as metals and oxygen sources, respectively, a competition between the metal precursors and the growth modes is observed. Indeed, while ferrocene promotes a 2D‐growth, nickelocene prefers a 3D‐growth. Although both precursors are homoleptic metallocenes, they behave differently in the ALD of their respective metal oxide, leading to unexpected atomic ratios and films morphologies of the iron‐nickel oxides. The 2Fe:1Ni sample displays the best performances in the electrochemical water oxidation (oxygen evolution reaction) exhibiting an overpotential of 267 mV at a current density of 10 mA cm−1, a Tafel slope of 36.8 mV dec−1, as well as a good stability after 15 h of continuous operation.

Abstract Bimetallic nickel‐iron based oxides are regarded as one of the most promising catalysts for the oxygen evolution reaction (OER). In this study, we show that the precursor metal salts can affect the OER activity of the resulting Ni/Fe oxide under the same hydrothermal synthesis conditions. Pure sulfate, pure nitrate and mixed sulfate/nitrate metal salts were used to fabricate NiFe based oxide materials and to study the importance of the precursor choice for the OER. The results show that the nature of the precursor used in the synthesis of the bimetallic nickel‐iron materials can influence different multi‐phase catalysts to form which effects the OER.

Abstract Rational design of efficient pH‐universal hydrogen evolution reaction catalysts to enable large‐scale hydrogen production via electrochemical water splitting is of great significance, yet a challenging task. Herein, Ru atoms in the Ru2P structure were replaced with M = Co, Ni, or Mo to produce M2−xRuxP nanocrystals. The metals show strong site preference, with Co and Ni occupying the tetrahedral sites and Ru the square pyramidal sites of the CoRuP and NiRuP Ru2P‐type structures. The presence of Co or Ni in the tetrahedral sites leads to charge redistribution for Ru and, according to density functional theory calculations, a significant increase in the Ru d‐band centers. As a result, the intrinsic activity of CoRuP and NiRuP increases considerably compared to Ru2P in both acidic and alkaline media. The effect is not observed for MoRuP, in which Mo prefers to occupy the pyramidal sites. In particular, CoRuP shows state‐of‐the‐art activity, outperforming Ru2P with Pt‐like activity in 0.5 M H2SO4 (η10 = 12.3 mV; η100 = 52 mV; turnover frequency (TOF) = 4.7 s−1). It remains extraordinarily active in alkaline conditions (η10 = 12.9 mV; η100 = 43.5 mV) with a TOF of 4.5 s−1, which is 4x higher than that of Ru2P and 10x that of Pt/C. Further increase in the Co content does not lead to drastic loss of activity, especially in alkaline medium, where, for example, the TOF of Co1.9Ru0.1P remains comparable to that of Ru2P and higher than that of Pt/C, highlighting the viability of the adopted approach to prepare cost‐efficient catalysts.

Abstract The electronic properties of metal halide perovskites (MHPs) are crucial for achieving the full potential of MHPs‐based optoelectronic devices, and they are extensively studied by photoelectron spectroscopy (PES). However, there are numerous complexities during PES measurements, which can result in inconsistent experimental data or even misinterpretation of results. Here, it is demonstrated that in the presence of charge selective junctions with MHPs, significant electronic energy level realignment can occur during PES measurements due to the sample excitation with high‐energy photons used in PES, amounting up to over 0.8 eV in the present case. This is caused by unbalanced charge carrier accumulation within the perovskite due to the charge‐selective interface. X‐ray photoelectron spectroscopy further reveals that photoexcitation due to bremsstrahlung, as produced in commonly employed twin‐anode lab‐sources, can readily produce sizable photoinduced shifts of core levels of MHPs films, whereas monochromatized X‐ray lab‐sources (irradiation flux reduced by >50 times by eliminating the bremsstrahlung) induce negligible shifts within the range of presently applied anode powers. The data and measurement conditions presented here are intended to enable others to obtain reliable MHP electronic property information from PES measurements.

Abstract Chiral molecules are known to behave as spin filters due to the chiral induced spin selectivity (CISS) effect. Chirality can be implemented in molecular semiconductors in order to study the role of the CISS effect in charge transport and to find new materials for spintronic applications. In this study, the design and synthesis of a new class of enantiopure chiral organic semiconductors based on the well‐known dinaphtho[2,3‐b:2,3‐f]thieno[3,2‐b]thiophene (DNTT) core functionalized with chiral alkyl side chains is presented. When introduced in an organic field‐effect transistor (OFET) with magnetic contacts, the two enantiomers, (R)‐DNTT and (S)‐DNTT, show an opposite behavior with respect to the relative direction of the magnetization of the contacts, oriented by an external magnetic field. Each enantiomer displays an unexpectedly high magnetoresistance over one preferred orientation of the spin current injected from the magnetic contacts. The result is the first reported OFET in which the current can be switched on and off upon inversion of the direction of the applied external magnetic field. This work contributes to the general understanding of the CISS effect and opens new avenues for the introduction of organic materials in spintronic devices.

Abstract 2D transition metal dichalcogenides (TMDCs) are atomically‐thick semiconductors with great potential for next‐generation optoelectronic applications, such as transistors and sensors. Their large surface‐to‐volume ratio makes them energy‐efficient but also extremely sensitive to the physical‐chemical surroundings. The latter must be carefully considered when predicting the electronic behavior, such as their energy level alignment, which ultimately affects the charge carrier injection and transport in devices. Here, local doping is demonstrated and thus adjusting the opto‐electronic properties of monolayer TMDCs (WSe2 and MoS2) by chemically engineering the surface of the supporting substrate. This is achieved by decorating the substrate by microcontact printing with patterns of two different self‐assembled monolayers (SAMs). The SAMs posses distinct molecular dipoles and dielectric constants, significantly influencing the TMDCs electronic and optical properties. By analyzing (on various substrtates), it is confirmed that these effects arise solely from the interaction between SAMs and TMDCs. Understanding the diverse dielectric environments experienced by TMDCs allows for a correlation between electronic and optical behaviours. The changes primarily involve alteration in the electronic band gap width, which can be calculated using the Schottky‐Mott rule, incorporating the dielectric screening of the TMDCs surroundings. This knowledge enables accurate prediction of the (opto‐)electronic behavior of monolayer TMDCs for advanced device design.

Although microscopic techniques have been used to characterize transition metal dichalcogenides (TMDs), direct observation of charge carrier dynamics distribution in TMDs with diverse shapes remains unexplored. Herein, ultrafast pump–probe microscopy (UPPM) is employed to reveal the carrier dynamics distribution in molybdenum disulfide (MoS2) and tungsten disulfide (WS2) monolayer of four shapes: triangular (t‐MoS2), curved triangular (c‐MoS2), triangular (t‐WS2), and hexagonal (h‐WS2). Monitoring the photon transmission T at 1.55 eV after pumping with a photon energy of 3.1 eV, a negative ΔT/T occurs in t‐MoS2 and c‐MoS2, while a positive ΔT/T is detected in t‐WS2 and h‐WS2 after 3–7 ps time evolution. This distinctive behavior is attributed to deep/shallow defects below the conduction band minimum (CBM) in MoS2 and WS2. Spatial‐independent ΔT/T is observed in t‐MoS2 and t‐WS2, while the ΔT/T in c‐MoS2 has a rapid decay of photoexcited carriers at the vertices and curved edges. Additionally, a threefold symmetry of ΔT/T is revealed in h‐WS2, attributed to the dissimilar occupation of defect states near the h‐WS2 CBM. This work paves the way for examining charge carrier dynamics of various shapes of TMDs and provides a unique microscopic method for studying the charge carrier dynamics in emerging TMDs heterostructures.

Abstract The charge transport of crystalline organic semiconductors is limited by dynamic disorder that tends to localize charges. It is the main hurdle to overcome in order to significantly increase charge carrier mobility. An innovative design that combines a chemical structure based on sulfur‐rich thienoacene with a solid‐state herringbone (HB) packing is proposed and the synthesis, physicochemical characterization, and charge transport properties of two new thienoacenes bearing a central tetrathienyl core fused with two external naphthyl rings: naphtho[2,3‐b]thieno‐[2′′′,3′′′:4′′,5′′]thieno[2″,3″:4′,5′]thieno[3′,2′‐b]naphtho[2,3‐b]thiophene (DN4T) and naphtho[1,2‐b]thieno‐[2′′′,3′′′:4′′,5′′]thieno[2′′,3′′:4′,5′]thieno[3′,2′‐b]naphtho[1,2‐b]thiophene are presented. Both compounds crystallize with a HB pattern structure and present transfer integrals ranging from 33 to 99 meV (for the former) within the HB plane of charge transport. Molecular dynamics simulations point toward an efficient resilience of the transfer integrals to the intermolecular sliding motion commonly responsible for strong variations of the electronic coupling in the crystal. Best device performances are reached with DN4T with hole mobility up to μ = 2.1 cm2 V−1s−1 in polycrystalline organic field effect transistors, showing the effectiveness of the electronic coupling enabled by the new aromatic core. These promising results pave the way to the design of high‐performing materials based on this new thienoacene, notably through the introduction of alkyl side‐chains.

Abstract Silicon‐based anodes with lithium ions as charge carriers have the highest predicted theoretical specific capacity of 3579 mA h g−1 (for Li15Si4). Contemporary electrodes do not achieve this theoretical value largely because conventional production paradigms rely on the mixing of weakly coordinated components. In this paper, a semiconductive triazine‐based graphdiyne polymer network is grown around silicon nanoparticles directly on the current collector, a copper sheet. The porous, semiconducting organic framework (1) adheres to the current collector on which it grows via cooperative van der Waals interactions, (2) acts effectively as conductor for electrical charges and binder of silicon nanoparticles via conjugated, covalent bonds, and (3) enables selective transport of electrolyte and Li‐ions through pores of defined size. The resulting anode shows extraordinarily high capacity at the theoretical limit of fully lithiated silicon. Finally, we combine our anodes in proof‐of‐concept battery assemblies using a conventional layered Ni‐rich oxide cathode. Key Points We present a Si‐based anode with superior‐performance close to the limits of theoretical capacities with an advantage of factor ×10 over any hitherto produced, commercial electrode system. Our electrodes sustain physical bending without surface reconstruction or crack formation, and heat shocks without loss of capacity and overall cycling performance. The critical, novelty that enables the extraordinary performance increase and durability of our anodes is a class of semi‐conducting porous organic polymers that replaces all conventional additives in battery ink formulations.

To fully unlock the potential of metal halide perovskites (MHPs) for use in optoelectronic devices, a comprehensive understanding of their electronic properties is in strong demand but presently lacking. This photoelectron spectroscopy study reveals that the thin films of three important mixed-cation/mixed-halide MHPs behave like intrinsic semiconductors with a very low defect concentration. The Fermi level position in the bandgap can be varied by almost 1 eV by choosing substrates of appropriate work function for samples that were handled under inert conditions. Upon oxygen exposure, two organic/inorganic-cation MHPs become strongly p-doped due to oxygen diffusion into the bulk, a process that is fully reversible when storing the samples in ultrahigh vacuum. In contrast, all-inorganic CsPbI1.8Br1.2 exhibits no electronic property changes upon oxygen exposure. Nonetheless, oxygen is found to effectively remove (light-induced) lead-related surface states of CsPbI1.8Br1.2.

Abstract Van der Waals heterostructures consisting of 2D semiconductors and conjugated molecules are of increasing interest because of the prospect of a synergistic enhancement of (opto)electronic properties. In particular, perylenetetracarboxylic dianhydride (PTCDA) on monolayer (ML)‐MoS2 has been identified as promising candidate and a staggered type‐II energy level alignment and excited state interfacial charge transfer have been proposed. In contrast, it is here found with inverse and direct angle resolved photoelectron spectroscopy that PTCDA/ML‐MoS2 supported by insulating sapphire exhibits a straddling type‐I level alignment, with PTCDA having the wider energy gap. Photoluminescence (PL) and sub‐picosecond transient absorption measurements reveal that resonance energy transfer, i.e., electron–hole pair (exciton) transfer, from PTCDA to ML‐MoS2 occurs on a sub‐picosecond time scale. This gives rise to an enhanced PL yield from ML‐MoS2 in the heterostructure and an according overall modulation of the photoresponse. These results underpin the importance of a precise knowledge of the interfacial electronic structure in order to understand excited state dynamics and to devise reliable design strategies for optimized optoelectronic functionality in van der Waals heterostructures.

Abstract Molecular doping allows enhancement and precise control of electrical properties of organic semiconductors, and is thus of central technological relevance for organic (opto‐) electronics. Beyond single‐component molecular electron acceptors and donors, organic salts have recently emerged as a promising class of dopants. However, the pertinent fundamental understanding of doping mechanisms and doping capabilities is limited. Here, the unique capabilities of the salt consisting of a borinium cation (Mes2B+; Mes: mesitylene) and the tetrakis(penta‐fluorophenyl)borate anion [B(C6F5)4]− is demonstrated as p‐type dopant for polymer semiconductors. With a range of experimental methods, the doping mechanism is identified to comprise electron transfer from the polymer to Mes2B+, and the positive charge on the polymer is stabilized by [B(C6F5)4]−. Notably, the former salt cation leaves during processing and is not present in films. The anion [B(C6F5)4]− even enables the stabilization of polarons and bipolarons in poly(3‐hexylthiophene), not yet achieved with other molecular dopants. From doping studies with high ionization energy polymer semiconductors, the effective electron affinity of Mes2B+[B(C6F5)4]− is estimated to be an impressive 5.9 eV. This significantly extends the parameter space for doping of polymer semiconductors.

Abstract The stability of hybrid perovskite materials for solar cells and high surface property reproducibility are important topics of present research. To understand the impact of water, oxygen, and air exposure, as experienced during typical device fabrication and operation conditions, on the surface electronic properties of solution‐processed CH3NH3PbI3–xClx perovskite thin films, and subsequently formed interfaces to other materials, a comprehensive photoelectron spectroscopy study is performed. It is shown that pure oxygen exposure reduces the typically observed pronounced n‐type surface character, while pure water exposure increases it. Very low water partial pressure, e.g., as encountered in inert‐gas glove boxes and in high vacuum of 10−6 mbar, reduces the perovskite work function due to water physisorption, which is fully reversible upon mild annealing (room temperature to 50 °C) in ultrahigh vacuum. Upon exposure to ambient air, the effect of oxygen prevails over that of water, and the perovskite become less n‐type as seen by a 0.6 eV Fermi level shift toward midgap. The results help in understanding variations of the surface electronic properties reported for perovskites, which in turn impact the energy level alignment at heterojunctions in devices. For future studies, the crucial importance of stringent environment control is stressed upon.

The human lymphocyte antigen (HLA) encoded BAT3/BAG6 recently attracted interest as a regulator of protein targeting and degradation, a function that could be exerted in the cytosol and in the nucleus. The BAT3 gene was described to consist of 25 exons. Diversity of transcripts can be generated by alternative RNA splicing, which may control subcellular distribution of BAT3.By cDNA sequencing we identified a novel alternatively spliced sequence of the BAT3 gene located between exons 11 and 12, which was designated as exon 11B. Using PCR and colony hybridization we identified six cDNA variants, which were produced by RNA splicing of BAT3 exons 5, 11B and 24. In four examined cell types the content of BAT3 splice variants was examined. Most of the cDNA clones from monocyte-derived dendritic cells contain exon 11B, whereas this sequence was almost absent in the B lymphoma Raji. Exon 5 was detected in most and exon 24 in approximately half of the cDNA clones. The subcellular distribution of endogenous BAT3 largely correlates with a cell type specific splicing pattern. In cells transfected with BAT3 variants, full-length and Δ24 BAT3 displayed nearly exclusive nuclear staining, whereas variants deleted of exon 11B showed substantial cytosolic expression. We show here that BAT3 is mainly expressed in the cytosol of Raji cells, while other cell types displayed both cytosolic and nuclear staining. Export of BAT3 from the nucleus to the cytosol is inhibited by treatment with leptomycin B, indicating that the Crm1 pathway is involved. Nuclear expression of BAT3 containing exon 11B suggests that this sequence plays a role for nuclear retention of the protein.Cell type-specific subcellular expression of BAT3 suggests distinct functions in the cytosol and in the nucleus. Differential expression of BAT3 variants may reconcile the multiple roles described for BAT3.

BACKGROUND: The HLA gene complex encodes three class II isotypes, DR, DQ, and DP. HLA class II molecules are peptide receptors that present antigens for recognition by T lymphocytes. In antigen presenting cells, the assembly of matched α and β subunits to heterodimers is chaperoned by invariant chain (Ii). Ii forms a homotrimer with three binding sites for class II heterodimers. The current model of class II and Ii structure states that three αβ heterodimers bind to an Ii trimer. METHODOLOGY/PRINCIPAL FINDINGS: [corrected] We have now analyzed the composition and size of the complexes of class II and Ii using epitope tagged class II subunits and density gradient experiments. We show here that class II-Ii oligomers consist of one class II heterodimer associated with one Ii trimer, such that the DR, DQ and DP isotypes are contained within separate complexes with Ii. CONCLUSION/SIGNIFICANCE: We propose a structural model of the class II-Ii oligomer and speculate that the pentameric class II-Ii complex is bent towards the cell membrane, inhibiting the binding of additional class II heterodimers to Ii.

To assess the formation of intra-island grain boundaries during the early stages of pentacene film growth, we studied sub-monolayers of pentacene on pristine silicon oxide and silicon oxide with high pinning centre density (induced by UV/O3treatment). We investigated the influence of the kinetic energy of the impinging molecules on the sub-monolayer growth by comparing organic molecular beam deposition (OMBD) and supersonic molecular beam deposition (SuMBD). For pentacene films fabricated by OMBD, higher pentacene island-density and higher polycrystalline island density were observed on UV/O3-treated silicon oxide as compared to pristine silicon oxide. Pentacene films deposited by SuMBD exhibited about one order of magnitude lower island- and polycrystalline island densities compared to OMBD, on both types of substrates. Our results suggest that polycrystalline growth of single islands on amorphous silicon oxide is facilitated by structural/chemical surface pinning centres, which act as nucleation centres for multiple grain formation in a single island. Furthermore, the overall lower intra-island grain boundary density in pentacene films fabricated by SuMBD reduces the number of charge carrier trapping sites specific to grain boundaries and should thus help achieving higher charge carrier mobilities, which are advantageous for their use in organic thin-film transistors. [ABSTRACT FROM AUTHOR]

We report on the formation of organic-organic thin film heterostructures by co-sublimation, which exhibit either mixing of compounds on the molecular scale or pronounced phase separation into ordered domains on the micrometre scale. The mixed structures may be used as active layers in organic field effect transistors, while phase separation is useful in organic bulk hetero-junction solar cells. Pairs of five rod-like conjugated molecules were co-deposited onto silicon oxide substrates in vacuum. With the five materials: pentacene (PEN), alpha-quaterthiophene (4T), alpha-sexithiophene (6T), p-sexiphenyl (6P), and alkyl chain substituted α,ω-dihexylsexithiophene (DH6T), we investigated molecule pairs, which differ in the length of the molecular conjugated core (CC) and the overall molecular length. Material pairs with similarly sized CC, such as 4T/PEN and 6T/6P, showed the formation of ordered layered structures with intimated mixing on a molecular level. On the other hand, pronounced phase separation was observed for material pairs of dissimilar CC lengths, e.g.4T/6T and PEN/DH6T. We propose that this can be generalized as design rule for the formation of either mixed or phase separated co-deposited molecular films. [ABSTRACT FROM AUTHOR]

Human HLA-DM or mouse H2-DM plays a vital role for presentation of antigenic sequences by MHC class II peptide receptors. These non-classical MHC class II molecules catalyze the release of the invariant chain (Ii) fragment CLIP from the class II cleft and facilitate acquisition of antigenic peptides by MHC class II peptide receptors. H2-DM- or Ii-deficient mice display an impaired ability of their antigen-presenting cell to present peptides to CD4+ T cells and a molecular link between the immunodeficiencies of these mouse strains may exist. We show that in transfected cells the presence of HLA-DM molecules in endocytic vesicles was strongly reduced when HLA-DM was accompanied by HLA-DR. Exclusion of HLA-DM from endocytic vesicles is explained by mixed association of HLA-DM with HLA-DR subunits and retention of the aggregates in the endoplasmic reticulum. Expression of Ii, however, impairs formation of mixed HLA-DR and HLA-DM complexes and directs matched pairing of HLA-DR and HLA-DM heterodimers. In Ii gene-deficient mice, aberrant association of H2A with H2-DM polypeptides was detected. Low expression of Ii in transgenic mice inhibits interaction of H2A with H2-DM subunits and facilitates formation of H2-DMαβ heterodimers. A role of Ii for assembly of H2-DM heterodimers partially explains the immunodeficient phenotype of Ii–/– mice. [ABSTRACT FROM AUTHOR]

Transparent and highly conductive graphene electrodes have been fabricated through acetylene-assisted thermolysis of graphite oxide (GO) sheets. This novel procedure uses acetylene as a supplemental carbon source to repair substantial defects within GO sheets, leading to the enhancement of graphitization of synthesized graphene electrodes. The as-prepared graphene on quartz substrates exhibits an electrical conductivity of 1425 S cm[?]1 with an optical transmittance of more than 70% at a wavelength of 500 nm. Such an acetylene-assisted thermal treatment approach is also adopted to fabricate graphene electrodes from synthetic nanographene molecules, with an almost five times increase in conductivity compared to samples prepared by the common thermal reduction. [ABSTRACT FROM AUTHOR]