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Two host materials o-CBPy and o-CPPy with bipolar charge transporting character were prepared via dipole moment engineering. Both blue and green phosphorescent OLEDs based on o-CBPy show very high efficiency (>30%) and small efficiency roll-off.

The CoP@BNPC-modified separator effectively inhibited the shuttle effect of LiPSs with strong adsorption capacity.

Modulating the surface electronic properties of the 2D MXenes is of significant importance to boost their hydrogen evolution reaction (HER) activity. Herein, a series of transition metal adatoms are employed to tune the surface electronic properties of Cr-based MXenes with oxygen function group for realizing impressive HER performance. The Results show that the charge of surface oxygen atoms, which is affected by both the host metal atoms and the adsorbed transition metal atoms, play critical role in the adsorption strength of hydrogen. The optimal performance is achieved by depositing Cr atom on the Cr2TiC2O2 MXene, which results in the adsorption free energy of hydrogen very close to zero (0.03 eV). Systematic electronic structure analyses confirm that the charge transfer from the adsorbed transition metals to the neighboring surface oxygen atoms could tune the orbital occupancy of oxygen and their adsorption strength to hydrogen atom and therefore the HER activity. These findings and concepts may be useful for the design of advanced MXene-based HER catalysts.

As a layered inorganic material, MoS2 has recently attracted intensive attention as anode for sodium ion batteries (SIBs). However, this anode is plagued with low electronic conductivity, serious volume expansion and sluggish kinetics, resulting in capacity fading and poor rate performance. Herein, we develop an interface engineering strategy to substantially enhance the sodium storage performance of MoS2 by incorporating layered MoS2 into three dimensional N-doped graphene scaffold. The strong coupling-interface between MoS2 and N-doped graphene scaffold can not only stabilize the MoS2 structure during sodium insertion/extraction processes, but also provide plenty of anchor sites for additional surface sodium storage. The 3D MoS2@N-doped graphene composite as anode for SIBs performs an outstanding specific capacity of 667.3 mA h g−1 at 0.2 A g−1, a prolonged stability with a capacity retention of 94.4% after 140 cycles and excellent rate capability of 445 mA h g−1 even at a high rate of 10 A g−1. We combined experiment and theoretical simulation to further disclose the interaction between MoS2 and N-doped graphene, adsorption and diffusion of sodium on the composite and the corresponding sodium storage mechanism. This study opens a new door to develop high performance SIBs by introducing the interface engineering technique.

Currently, MXenes have been identified as promising candidate electrode materials for Na-ion batteries because of their excellent energy storage and electrical conductivity. Among them, dual transition metal MXenes have attracted attention due to their excellent properties as anode materials for Na-ion batteries. In order to explore the reason why dual transition metal MXenes outperform single transition metal MXenes, we systemically investigated and compared the performance of TiNbC-based dual transition metal MXenes (TiNbC, TiNbCF2, and TiNbCO2) with that of Nb2C-based single transition metal MXenes (Nb2C, Nb2CF2, and Nb2CO2) as anode materials for Na-ion batteries based density functional theory calculations. The results showed that TiNbC, TiNbCO2, Nb2C, and Nb2CO2 are promising anode materials for Na-ion batteries due to the low diffusion barrier and high capacity of Na on their surfaces. Compared with the Nb2C-based single transition metal MXenes, the TiNbC-based dual transition metal MXenes have better adsorption performance, diffusion rate, and theoretical storage of Na atoms. The higher adsorption ability of TiNbC and TiNbCO2 to Na atoms was attributed to the synergistic effect of Ti and Nb which increases the interaction between the substrate and Na. This conclusion provides a new insight for the development of other high-performance MXenes-based anode materials for Na-ion batteries.

Printed electronics, which fabricate electrical components and circuits on various substrates by leveraging functional inks and advanced printing technologies, have recently attracted tremendous attention due to their capability of large-scale, high-speed, and cost-effective manufacturing and also their great potential in flexible and wearable devices. To further achieve multifunctional, practical, and commercial applications, various printing technologies toward smarter pattern-design, higher resolution, greater production flexibility, and novel ink formulations toward multi-functionalities and high quality have been insensitively investigated. 2D materials, possessing atomically thin thickness, unique properties and excellent solution-processable ability, hold great potential for high-quality inks. Besides, the great variety of 2D materials ranging from metals, semiconductors to insulators offers great freedom to formulate versatile inks to construct various printed electronics. Here, a detailed review of the progress on 2D material inks formulation and its printed applications has been provided, specifically with an emphasis on emerging printed memristors. Finally, the challenges facing the field and prospects of 2D material inks and printed electronics are discussed.

The design of new cathode materials is vital to develop the high performance proton exchange membrane fuel cell (PEMFC). The adsorption properties of the species involved in the oxygen reduction reaction (ORR) and several ORR mechanisms on phosphorene were presented with using the first-principle calculations. Results show that the H adsorption is more preferable than O2, and the OOH spontaneously form from the adsorbed H and O2. The HOOH from the hydrogenation of the OOH species could be further hydrogenated into OH and H2O, and the OH would be finally hydrogenated into the (second) H2O. The reaction barrier of rate-determining step is 1.02 eV. Moreover, the presented kinetic processes are confirmed by the thermodynamic simulation from Gibbs free energy calculations and molecular dynamics simulations. These results indicate that phosphorene as one of new 2D materials could be a promising metal free cathode material for PEMFC.

Carbon materials with a novel structure have been considered to be potential anodes for sodium ion batteries (SIBs). However, the practical utilization of a carbon electrode for SIBs suffers from low initial coulombic efficiency and poor ion diffusion kinetics. Moreover, the sodium storage mechanism still remains controversial. Herein, well-ordered 3D porous phosphorus doped carbon was designed and developed as an anode material for SIBs, which delivers an excellent reversible capacity of 270 mA h g−1 at 0.2 A g−1 and a good rate capability of 140 mA h g−1 even at 10 A g−1. The correlation of experimental results and theoretical calculation confirms that phosphorus doping into the carbon material could increase the interlayer distance, enhance the adsorption of sodium ions and modify the electronic structure, and thus can promote the efficient sodium insertion/extraction and charge transfer kinetics. Moreover, the interconnected porous carbon structure is facile to promote the permeation of the electrolyte for transportation and diffusion of ions and electrons. This synthetic strategy provides an efficient and simple approach to prepare well-ordered 3D porous heteroatom-doped carbon for SIBs and other energy storage devices.