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Bioinspired assemblies bear massive potential for energy generation and storage. Yet, biological molecules have severe limitations for charge transfer. Here, we report L -tryptophan- D -tryptophan assembling architectures comprising alternating water and peptide layers. The extensive connection of water molecules results in significant dipole–dipole interactions and piezoelectric response that can be further engineered by doping via iodine adsorption or isotope replacement with no change in the chemical composition. This simple system and the new doping strategies supply alternative solutions for enhancing charge transfer in bioinspired supramolecular architectures.

Highly efficient, stable and cost-efficient electrocatalysts for hydrogen generation via water splitting have become in increasing demand for future energy systems. Hitherto, P-rich noble metal polyphosphides which can decrease noble metal (such as Rh, Pd, or Ir) dosage are important to probe potential high-performance HER electrocatalysts. Nevertheless, they are difficult to synthesize at ambient pressure and moderate temperatures. Herein, for the first time, we report a novel iridium diphosphide (IrP 2 ) electrocatalyst embedded within an ultrathin nitrogen-doped carbon (NC) layer (IrP 2 @NC) synthesized at ambient pressure and moderate temperature (900 °C). Subsequent electrochemical tests revealed that such a P-rich IrP 2 @NC catalyst possesses the highest hydrogen evolution reaction (HER) activity among all the documented transition metal phosphide electrocatalysts, including the commercial Pt/C, with ultralow overpotentials of 8 and 28 mV to achieve 10 mA cm ?2 in 0.5 M H 2 SO 4 and 1.0 M KOH, respectively. Combined density functional theory (DFT) computational studies suggest that the introduction of phosphorus into iridium can weaken the H adsorption strength of IrP 2 , beneficial for boosting HER activity. More importantly, this synthetic strategy for P-rich IrP 2 @NC can also be applied to other noble metal diphosphides (RhP 2 @NC and Pd 5 P 2 @NC, etc. ). This work presents a particularly efficient and stable P-rich transition metal polyphosphide with advanced HER performance and beyond.

Bifunctional catalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are highly desirable for rechargeable metal–air batteries and regenerative fuel cells. However, the commercial oxygen electrocatalysts (mainly noble metal based) can only exhibit either ORR or OER activity and also suffer from inherent cost and stability issues. It remains challenging to achieve efficient ORR and OER bifunctionality on a single catalyst. Metal-free structures offer relatively large scope for this bifunctionality to be engineered within one catalyst, together with improved cost-effectiveness and durability. Herein, by closely coupled computational design and experimental development, highly effective bifunctionality was achieved in a phosphorus and nitrogen co-doped graphene framework (PNGF) – with both ORR and OER activities reaching the theoretical limits of metal-free catalysts, superior to their noble metal counterparts in both (bi)functionality and durability. In particular, with the identification of active P–N sites for OER and N-doped sites for ORR, we successfully intensified these sites by one-pot synthesis to tailor the PNGF. The resulting catalyst achieved an ORR potential of 0.845 V vs. RHE at 3 mA cm ?2 and an OER potential of 1.55 V vs. RHE at 10 mA cm ?2 . Its combined ORR and OER overpotential of 705 mV is much lower than those previously reported for metal-free bifunctional catalysts.

Half electrolysis consists of a single faradaic reaction and a supercapacitor electrode. The electrolytic product is only produced at the faradaic electrode and the low voltage electrolysis is highly energy efficient.

Optoelectronic devices typically require low-resistance ohmic contacts between the optical active layers and metal electrodes. Failure to make such a contact often results in a Schottky barrier which inhibits charge extraction and, in turn, reduces device performance. Here, we introduce a universal solution processable metal-oxide/organic interfacial bilayer which forms a near-perfect ohmic contact between both organic and inorganic semiconductors and metals. This bilayer comprises a Nb-doped TiO 2 metal oxide with enhanced electron mobility and reduced trap density compared to pristine TiO 2 , in combination with a metal-chelating organic molecule to make an intimate electrical contact with silver metallic electrodes. Using this universal interfacial bilayer, we demonstrate substantial efficiency improvements in organic solar cells (from 9.3% to 12.6% PCE), light emitting diodes (from 0.6 to 2.2 cd W ?1 ) and transistors (from 19.7 to 13.9 V threshold voltage). In particular, a boost in efficiency for perovskite solar cells (from 18.7% up to 20.7% PCE) with up to 83% fill factor is achieved with no-operational lifetime loss for at least 1000 hours under continuous, full-spectrum illumination.

A flexible and widely applicable method allows the deposition of carbon-doped visible light-activated photocatalytic TiO 2 thin films on a variety of substrates.

Alkaline polymer electrolytes (APEs) are a new class of polyelectrolytes enabling the use of nonprecious metal catalysts in electrochemical devices, such as fuel cells and water electrolyzers. However, the current development of APEs is facing a severe difficulty, the conductivity–stability dilemma. Specifically, to acquire high ionic conductivity, the polymer backbone has to be grafted with enough cationic functional groups, typically quaternary ammonium (–NR 3 + ), but such a modification in structure has damaged the chemical inertness of the polymer backbone and induced degradation in an alkaline environment. Here we demonstrate a strategy for disentangling such a dilemma. To alleviate the damage to the polymer backbone, we reduce the grafting degree (GD) of functional groups, but design two cations on each grafted functional group so as to retain sufficient ion concentration. Such a seemingly simple change in structure has brought a notable effect in performance: not only can both high ionic conductivity and much improved chemical stability be achieved, but also the intermolecular interaction between polymer chains has thus been enhanced, rendering the resulting APE membrane much stronger in mechanical strength and highly anti-swelling in water even at 80 °C.

Here we show polymer solar cells manufactured using only printing and coating of abundant materials directly on flexible plastic substrates or barrier foil using only roll-to-roll methods. Central to the development is a particular roll-to-roll compatible post-processing step that converts the pristine and non-functional multilayer-coated stack into a functional solar cell through formation of a charge selective interface, in situ , following a short electrical pulse with a high current density. After the fast post-processing step the device stack becomes active and all devices are functional with a technical yield and consistency that is compelling.

We report that a heat-treated Li 2 S–P 2 S 5 glass-ceramic conductor has an extremely high ionic conductivity of 1.7 × 10 ?2 S cm ?1 and the lowest conduction activation energy of 17 kJ mol ?1 at room temperature among lithium-ion conductors reported to date. The optimum conditions of the heat treatment reduce the grain boundary resistance, and the influence of voids, to increase the Li + ionic conductivity of the solid electrolyte so that it is greater than the conductivities of liquid electrolytes, when the transport number of lithium ions in the inorganic electrolyte is unity.

This paper gives a comprehensive review about the most recent progress in synthesis, characterization, fundamental understanding, and the performance of graphene and graphene oxide sponges. Practical applications are considered including use in composite materials, as the electrode materials for electrochemical sensors, as absorbers for both gases and liquids, and as electrode materials for devices involved in electrochemical energy storage and conversion. Several advantages of both graphene and graphene oxide sponges such as three dimensional graphene networks, high surface area, high electro/thermo conductivities, high chemical/electrochemical stability, high flexibility and elasticity, and extremely high surface hydrophobicity are emphasized. To facilitate further research and development, the technical challenges are discussed, and several future research directions are also suggested in this paper.