Small-Molecule Mixed Ionic-Electronic Conductors for Efficient N-Type Electrochemical Transistors: Structure-Function Correlations.

The fundamental challenge in electron-transporting organic mixed ionic-electronic conductors (OMIECs) is simultaneous optimization of electron and ion transport. Beginning from Y6-type/U-shaped non-fullerene solar cell acceptors, we systematically synthesize and characterize molecular structures that address the aforementioned challenge, progressively introducing increasing numbers of oligoethyleneglycol (OEG; g) sidechains from 1g to 3g, affording OMIECs 1gY, 2gY, and 3gY, respectively. The crystal structure of 1gY preserves key structural features of the Yn series: a U-shaped/planar core, close π-π molecular stacking, and interlocked acceptor groups. Versus inactive Y6 and Y11, all of the new glycolated compounds exhibit mixed ion-electron transport in both conventional organic electrochemical transistor (cOECT) and vertical OECT (vOECT) architectures. Notably, 3gY with the highest OEG density achieves a high normalized transconductance of 25.29 S cm-1, an on/off current ratio of ~106, and a turn-on/off response time of 94.7/5.7 ms in vOECTs. Systematic optoelectronic, electrochemical, architectural, and crystallographic analysis explains the superior 3gY-based OECT performance in terms of denser ngY OEG content, increased crystallite dimensions with decreased long-range crystalline order, and enhanced film hydrophilicity which facilitates ion transport and efficient redox processes. Finally, we demonstrate an efficient small-molecule-based complementary inverter using 3gY vOECTs, showcasing the bioelectronic applicability of these new small-molecule OMIECs.

Monolithically integrated high-density vertical organic electrochemical transistor arrays and complementary circuits.

Organic electrochemical transistors (OECTs) can be used to create biosensors, wearable devices and neuromorphic systems. However, restrictions in the micro- and nanopatterning of organic semiconductors, as well as topological irregularities, often limit their use in monolithically integrated circuits. Here we show that the micropatterning of organic semiconductors by electron-beam exposure can be used to create high-density (up to around 7.2 million OECTs per cm2) and mechanically flexible vertical OECT arrays and circuits. The energetic electrons convert the semiconductor exposed area to an electronic insulator while retaining ionic conductivity and topological continuity with the redox-active unexposed areas essential for monolithic integration. The resulting p- and n-type vertical OECT active-matrix arrays exhibit transconductances of 0.08-1.7 S, transient times of less than 100 µs and stable switching properties of more than 100,000 cycles. We also fabricate vertically stacked complementary logic circuits, including NOT, NAND and NOR gates.

Demystifying group-4 polyolefin hydrogenolysis catalysis. Gaseous propane hydrogenolysis mechanism over the same catalysts.

A kinetic/mechanistic investigation of gaseous propane hydrogenolysis over the single-site heterogeneous polyolefin depolymerization catalysts AlS/ZrNp2 and AlS/HfNp2 (AlS = sulfated alumina, Np = neopentyl), is use to probe intrinsic catalyst properties without the complexities introduced by time- and viscosity-dependent polymer medium effects. In a polymer-free automated plug-flow catalytic reactor, propane hydrogenolysis turnover frequencies approach 3,000 h-1 at 150 °C. Both catalysts exhibit approximately linear relationships between rate and [H2] at substoichiometric [H2] with rate law orders of 0.66 ± 0.09 and 0.48 ± 0.07 for Hf and Zr, respectively; at higher [H2], the rates approach zero-order in [H2]. Reaction orders in [C3H8] and [catalyst] are essentially zero-order under all conditions, with the former implying rapid, irreversible alkane binding/activation. This rate law, activation parameter, and DFT energy span analysis support a scenario in which [H2] is pivotal in one of two plausible and competing rate-determining transition states-bimolecular metal-alkyl bond hydrogenolysis vs. unimolecular ß-alkyl elimination. The Zr and Hf catalyst activation parameters, ΔH‡ = 16.8 ± 0.2 kcal mol-1 and 18.2 ± 0.6 kcal mol-1, respectively, track the relative turnover frequencies, while ΔS‡ = -19.1 ± 0.8 and -16.7 ± 1.4 cal mol-1 K-1, respectively, imply highly organized transition states. These catalysts maintain activity up to 200 °C, while time-on-stream data indicate multiday activities with an extrapolated turnover number ~92,000 at 150 °C for the Zr catalyst. This methodology is attractive for depolymerization catalyst discovery and process optimization.

Two-dimensional perovskitoids enhance stability in perovskite solar cells.

Two-dimensional (2D) and three-dimensional (3D) perovskite heterostructures have played a key role in advancing the performance of perovskite solar cells1,2. However, the migration of cations between 2D and 3D layers results in the disruption of octahedral networks, leading to degradation in performance over time3,4. We hypothesized that perovskitoids, with robust organic-inorganic networks enabled by edge- and face-sharing, could impede ion migration. We explored a set of perovskitoids of varying dimensionality and found that cation migration within perovskitoid-perovskite heterostructures was suppressed compared with the 2D-3D perovskite case. Increasing the dimensionality of perovskitoids improves charge transport when they are interfaced with 3D perovskite surfaces-this is the result of enhanced octahedral connectivity and out-of-plane orientation. The 2D perovskitoid (A6BfP)8Pb7I22 (A6BfP: N-aminohexyl-benz[f]-phthalimide) provides efficient passivation of perovskite surfaces and enables uniform large-area perovskite films. Devices based on perovskitoid-perovskite heterostructures achieve a certified quasi-steady-state power conversion efficiency of 24.6% for centimetre-area perovskite solar cells. We removed the fragile hole transport layers and showed stable operation of the underlying perovskitoid-perovskite heterostructure at 85 °C for 1,250 h for encapsulated large-area devices in ambient air.

On-Demand Catalysed n-Doping of Organic Semiconductors.

A new approach to control the n-doping reaction of organic semiconductors is reported using surface-functionalized gold nanoparticles (f-AuNPs) with alkylthiols acting as the catalyst only upon mild thermal activation. To demonstrate the versatility of this methodology, the reaction of the n-type dopant precursor N-DMBI-H with several molecular and polymeric semiconductors at different temperatures with/without f-AuNPs, vis-à-vis the unfunctionalized catalyst AuNPs, was investigated by spectroscopic, morphological, charge transport, and kinetic measurements as well as, computationally, the thermodynamic of catalyst activation. The combined experimental and theoretical data demonstrate that while f-AuNPs is inactive at room temperature both in solution and in the solid state, catalyst activation occurs rapidly at mild temperatures (~70 °C) and the doping reaction completes in few seconds affording large electrical conductivities (~10-140 S cm-1). The implementation of this methodology enables the use of semiconductor+dopant+catalyst solutions and will broaden the use of the corresponding n-doped films in opto-electronic devices such as thin-film transistors, electrochemical transistors, solar cells, and thermoelectrics well as guide the design of new catalysts.

Orientation and morphology control in acid-catalyzed covalent organic framework thin films.

As thin films of semiconducting covalent organic frameworks (COFs) are demonstrating utility for ambipolar electronics, channel materials in organic electrochemical transistors (OECTs), and broadband photodetectors, control and modulation of their thin film properties is paramount. In this work, an interfacial growth technique is utilized to synthesize imine TAPB-PDA COF films at both the liquid-liquid interface as well as at the liquid-solid interface on a Si/SiO2 substrate. The concentration of acetic acid catalyst in the aqueous phase is shown to significantly influence the thin film morphology of the liquid-solid growth, with concentrations below 1 M resulting in no film nucleation, concentrations of 1-4 M enabling smooth film formation, and concentrations greater than 4 M resulting in films with a higher density of particulates on the surface. Importantly, while the films grown at the liquid-liquid interface are mixed-orientation, those grown directly at the liquid-solid interface on the Si/SiO2 surface have highly oriented COF layers aligned parallel to the substrate surface. Moreover, this liquid-solid growth process affords TAPB-PDA COF thin films with p-type charge transport having a transconductance of 10 µS at a gate voltage of -0.9 V in an OECT device structure.

Trifluoromethylation of 2D Transition Metal Dichalcogenides: A Mild Functionalization and Tunable p-Type Doping Method.

Chemical modification is a powerful strategy for tuning the electronic properties of 2D semiconductors. Here we report the electrophilic trifluoromethylation of 2D WSe2 and MoS2 under mild conditions using the reagent trifluoromethyl thianthrenium triflate (TTT). Chemical characterization and density functional theory calculations reveal that the trifluoromethyl groups bind covalently to surface chalcogen atoms as well as oxygen substitution sites. Trifluoromethylation induces p-type doping in the underlying 2D material, enabling the modulation of charge transport and optical emission properties in WSe2. This work introduces a versatile and efficient method for tailoring the optical and electronic properties of 2D transition metal dichalcogenides.

Redesigned Nylon 6 Variants with Enhanced Recyclability, Ductility, and Transparency.

Geminal (gem-) disubstitution in heterocyclic monomers is an effective strategy to enhance polymer chemical recyclability by lowering their ceiling temperatures. However, the effects of specific substitution patterns on the monomer's reactivity and the resulting polymer's properties are largely unexplored. Here we show that, by systematically installing gem-dimethyl groups onto ϵ-caprolactam (monomer of nylon 6) from the α to ϵ positions, both the redesigned lactam monomer's reactivity and the resulting gem-nylon 6's properties are highly sensitive to the substitution position, with the monomers ranging from non-polymerizable to polymerizable and the gem-nylon properties ranging from inferior to far superior to the parent nylon 6. Remarkably, the nylon 6 with the gem-dimethyls substituted at the γ position is amorphous and optically transparent, with a higher Tg (by 30 °C), yield stress (by 1.5 MPa), ductility (by 3×), and lower depolymerization temperature (by 60 °C) than conventional nylon 6.

General room-temperature Suzuki-Miyaura polymerization for organic electronics.

π-Conjugated polymers (CPs) have broad applications in high-performance optoelectronics, energy storage, sensors and biomedicine. However, developing green and efficient methods to precisely synthesize alternating CP structures on a large scale remains challenging and critical for their industrialization. Here a room-temperature, scalable and homogeneous Suzuki-Miyaura-type polymerization reaction is developed with broad generality validated for 24 CPs including donor-donor, donor-acceptor and acceptor-acceptor connectivities, yielding device-quality polymers with high molecular masses. Furthermore, the polymerization protocol significantly reduces homocoupling structural defects, yielding more structurally regular and higher-performance electronic materials and optoelectronic devices than conventional thermally activated polymerizations. Experimental and theoretical studies reveal that a borate transmetalation process plays a key role in suppressing protodeboronation, which is critical for large-scale structural regularity. Thus, these results provide a general polymerization tool for the scalable production of device-quality CPs with alternating structural regularity.

Trauma and comorbid post-traumatic stress disorder in people with bipolar disorder participating in the Heinz C. Prechter Longitudinal Study.

BACKGROUND: It is estimated that up to 50 % of people with bipolar disorder (BD) also have comorbid post-traumatic stress disorder (PTSD). However, little is known about the presentation and treatment of people with this comorbidity. METHODS: Data from 577 individuals diagnosed with bipolar disorder participating in the Heinz C. Prechter Longitudinal Study of BD were explored at baseline, year two and four. Three trauma groups were created: (i) one trauma (n = 75), (ii) multiple traumas (n = 417), and comorbid PTSD (n = 85). Measures of depression, mania, sleep, number of hospitalisations, suicide attempts, and medication use were analysed using regression modelling to determine differences between the three trauma groups. RESULTS: There was an increase in depression, mania, and sleep scores and a higher number of hospitalisations in participants with comorbid PTSD compared to those experiencing one trauma. Additionally, increased mania and depression scores were reported in participants experiencing multiple traumas compared to those with one trauma. There was no difference in medication use between those who experienced one trauma compared to those with comorbid PTSD. LIMITATIONS: The trauma groups may include confounding with more participants experiencing PTSD than reported in this study due to screening processes. Additionally, the severity of trauma was not recorded, therefore number of traumas was utilised as a proxy. CONCLUSION: Comorbid BD and PTSD is associated with worse symptom scores compared to participants reporting one trauma. Clinical implications include the addition of trauma-informed care to clinical settings to identify PTSD to provide appropriate treatments.

Why do hosts malfunction without microbes? Missing benefits versus evolutionary addiction.

Microbes are widely recognized to be vital to host health. This new consensus rests, in part, on experiments showing how hosts malfunction when microbes are removed. More and more microbial dependencies are being discovered, even in fundamental processes such as development, immunity, physiology, and behavior. But why do they exist? The default explanation is that microbes are beneficial; when hosts lose microbes, they also lose benefits. Here I call attention to evolutionary addiction, whereby a host trait evolves a need for microbes without having been improved by them. Evolutionary addiction should be considered when interpreting microbe-removal experiments, as it is a distinct and potentially common process. Further, it may have unique implications for the evolution and stability of host-microbe interactions.

Recent Advances in Low-Dimensional Nanomaterials for Photodetectors.

New emerging low-dimensional such as 0D, 1D, and 2D nanomaterials have attracted tremendous research interests in various fields of state-of-the-art electronics, optoelectronics, and photonic applications due to their unique structural features and associated electronic, mechanical, and optical properties as well as high-throughput fabrication for large-area and low-cost production and integration. Particularly, photodetectors which transform light to electrical signals are one of the key components in modern optical communication and developed imaging technologies for whole application spectrum in the daily lives, including X-rays and ultraviolet biomedical imaging, visible light camera, and infrared night vision and spectroscopy. Today, diverse photodetector technologies are growing in terms of functionality and performance beyond the conventional silicon semiconductor, and low-dimensional nanomaterials have been demonstrated as promising potential platforms. In this review, the current states of progress on the development of these nanomaterials and their applications in the field of photodetectors are summarized. From the elemental combination for material design and lattice structure to the essential investigations of hybrid device architectures, various devices and recent developments including wearable photodetectors and neuromorphic applications are fully introduced. Finally, the future perspectives and challenges of the low-dimensional nanomaterials based photodetectors are also discussed.

Rapid Polyolefin Hydrogenolysis by a Single-Site Organo-Tantalum Catalyst on a Super-Acidic Support: Structure and Mechanism.

The novel electrophilic organo-tantalum catalyst AlS/TaNpx (1) (Np=neopentyl) is prepared by chemisorption of the alkylidene Np3 Ta=CHt Bu onto highly Brønsted acidic sulfated alumina (AlS). The proposed catalyst structure is supported by EXAFS, XANES, ICP, DRIFTS, elemental analysis, and SSNMR measurements and is in good agreement with DFT analysis. Catalyst 1 is highly effective for the hydrogenolysis of diverse linear and branched hydrocarbons, ranging from C2 to polyolefins. To the best of our knowledge, 1 exhibits one of the highest polyolefin hydrogenolysis activities (9,800 (CH2 units) ⋅ mol(Ta)-1 ⋅ h-1 at 200 °C/17 atm H2 ) reported to date in the peer-reviewed literature. Unlike the AlS/ZrNp2 analog, the Ta catalyst is more thermally stable and offers multiple potential C-C bond activation pathways. For hydrogenolysis, AlS/TaNpx is effective for a wide variety of pre- and post-consumer polyolefin plastics and is not significantly deactivated by standard polyolefin additives at typical industrial concentrations.

New insights into the electronic structure ofα-U andδ-Pu.

This work presents the results of a theoretical study of the electronic structure of two actinide metals,α-U andδ-Pu. We compare ourab-initioresults obtained with the recently developed self-consistent Vertex corrected GW approach with previously published experimental measurements such as photo-electron spectroscopy, for the occupied density of states, and bremsstralung isochromat spectroscopy (BIS) and inverse photo-electron spectroscopy (IPES), for the unoccupied density of states. Ourab-initioapproach includes all important relativistic effects (it is based on Dirac's equation) and it represents the first application of the Vertex corrected GW approach in the physics of actinides. Overall, our theoretical results are in good agreement with the experimental data, which supports the level of approximations which our theoretical method is based upon. By comparing our vertex corrected GW results with our results obtained with less sophisticated approaches (local density approximation and self-consistent GW) we differentiate the strength of correlation effects in Uranium and Plutonium. Also, our theoretical results allow us to elucidate the subtle differences between the previously published experimental BIS and IPES data on the unoccupied density of states inα-U.

Electroluminescence from Megasonically Solution-Processed MoS2 Nanosheet Films.

Due to their superior optoelectronic properties, monolayer two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted significant attention for electroluminescent devices. However, challenges in isolating optoelectronically active TMD monolayers using scalable liquid phase exfoliation have precluded electroluminescence in large-area, solution-processed TMD films. Here, we overcome these limitations and demonstrate electroluminescence from molybdenum disulfide (MoS2) nanosheet films by employing a monolayer-rich MoS2 ink produced by electrochemical intercalation and megasonic exfoliation. Characteristic monolayer MoS2 photoluminescence and electroluminescence spectral peaks at 1.88-1.90 eV are observed in megasonicated MoS2 films, with the emission intensity increasing with film thickness over the range 10-70 nm. Furthermore, employing a vertical light-emitting capacitor architecture enables uniform electroluminescence in large-area devices. These results indicate that megasonically exfoliated MoS2 monolayers retain their direct bandgap character in electrically percolating thin films even following multistep solution processing. Overall, this work establishes megasonicated MoS2 inks as an additive manufacturing platform for flexible, patterned, and miniaturized light sources that can likely be expanded to other TMD semiconductors.

Nickel-Doped Graphite and Fusible Alloy Bilayer Back Electrode for Vacuum-Free Perovskite Solar Cells.

With the rapid development of perovskite solar cells (PSCs), lowering fabrication costs for PSCs has become a prominent challenge for commercialization. At present, gold is commonly used as the back metal electrode in state-of-the-art n-i-p structured PSCs due to its compatible work function, chemical inertness, and high conductivity. However, the high cost of gold and the expensive and time-consuming vacuum-based thin-film coating facilities may impede large-scale industrialization of PSCs. Here, we report a bilayer back electrode configuration consisting of an Ni-doped natural graphite layer with a fusible Bi-In alloy. This back electrode can be deposited in a vacuum-free approach and enables PSCs with a power conversion efficiency of 21.0%. These inexpensive materials and facile ambient fabrication techniques provide an appealing disruptive solution to low-cost PSC industrialization.

Efficacy of immune checkpoint inhibitors for the treatment of advanced melanoma in patients with concomitant chronic lymphocytic leukemia.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have revolutionized the management of advanced melanoma (AM). However, data on ICI effectiveness have largely been restricted to clinical trials, thereby excluding patients with co-existing malignancies. Chronic lymphocytic leukemia (CLL) is the most prevalent adult leukemia and is associated with increased risk of melanoma. CLL alters systemic immunity and can induce T-cell exhaustion, which may limit the efficacy of ICIs in patients with CLL. We, therefore, sought to examine the efficacy of ICI in patients with these co-occurring diagnoses. PATIENTS AND METHODS: In this international multicenter study, a retrospective review of clinical databases identified patients with concomitant diagnoses of CLL and AM treated with ICI (US-MD Anderson Cancer Center, N = 24; US-Mayo Clinic, N = 15; AUS, N = 19). Objective response rates (ORRs), assessed by RECIST v1.1, and survival outcomes [overall survival (OS) and progression-free survival (PFS)] among patients with CLL and AM were assessed. Clinical factors associated with improved ORR and survival were explored. Additionally, ORR and survival outcomes were compared between the Australian CLL/AM cohort and a control cohort of 148 Australian patients with AM alone. RESULTS: Between 1997 and 2020, 58 patients with concomitant CLL and AM were treated with ICI. ORRs were comparable between AUS-CLL/AM and AM control cohorts (53% versus 48%, P = 0.81). PFS and OS from ICI initiation were also comparable between cohorts. Among CLL/AM patients, a majority were untreated for their CLL (64%) at the time of ICI. Patients with prior history of chemoimmunotherapy treatment for CLL (19%) had significantly reduced ORRs, PFS, and OS. CONCLUSIONS: Our case series of patients with concomitant CLL and melanoma demonstrate frequent, durable clinical responses to ICI. However, those with prior chemoimmunotherapy treatment for CLL had significantly worse outcomes. We found that CLL disease course is largely unchanged by treatment with ICI.

Oxidative-Reductive Near-Infrared Electrochromic Switching Enabled by Porous Vertically Stacked Multilayer Devices.

Here, we demonstrate for the first time the ability of a porous π-conjugated semiconducting polymer film to enable facile electrolyte penetration through vertically stacked redox-active polymer layers, thereby enabling electrochromic switching between p-type and/or n-type polymers. The polymers P1 and P2, with structures diketopyrrolopyrrole (DPP)-πbridge-3,4,-ethylenedioxythiophene (EDOT)-πbridge [πbridge = 2,5-thienyl for P1 and πbridge = 2,5-thiazolyl for P2] are selected as the p-type polymers and N2200 (a known naphthalenediimide-dithiophene semiconductor) as the n-type polymer. Single-layer porous and dense (control) polymer films are fabricated and extensively characterized using optical microscopy, atomic force microscopy, scanning electron microscopy, and grazing incidence wide-angle X-ray scattering. The semiconducting films are then incorporated into single and multilayer electrochromic devices (ECDs). It is found that when a p-type (P2) porous top layer is used in a multilayer ECD, it enables electrolyte penetration to the bottom layer, enabling oxidative electrochromic switching of the P1 bottom layer at low potentials (+0.4 V versus +1.2 V with dense P2). Importantly, when using a porous P1 as the top layer with an n-type N2200 bottom layer, dynamic oxidative-reductive electrochromic switching is also realized. These results offer a proof of concept for development of new types of multilayer electrochromic devices where precise control of the semiconductor film morphology and polymer electronic structure is essential.